--- /dev/null
+/*-------------------------------------------------------------------------
+ *
+ * nbtpreprocesskeys.c
+ * Preprocessing for Postgres btree scan keys.
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/access/nbtree/nbtpreprocesskeys.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/nbtree.h"
+#include "lib/qunique.h"
+#include "utils/array.h"
+#include "utils/lsyscache.h"
+#include "utils/memutils.h"
+
+typedef struct BTScanKeyPreproc
+{
+ ScanKey inkey;
+ int inkeyi;
+ int arrayidx;
+} BTScanKeyPreproc;
+
+typedef struct BTSortArrayContext
+{
+ FmgrInfo *sortproc;
+ Oid collation;
+ bool reverse;
+} BTSortArrayContext;
+
+static bool _bt_fix_scankey_strategy(ScanKey skey, int16 *indoption);
+static void _bt_mark_scankey_required(ScanKey skey);
+static bool _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
+ ScanKey leftarg, ScanKey rightarg,
+ BTArrayKeyInfo *array, FmgrInfo *orderproc,
+ bool *result);
+static bool _bt_compare_array_scankey_args(IndexScanDesc scan,
+ ScanKey arraysk, ScanKey skey,
+ FmgrInfo *orderproc, BTArrayKeyInfo *array,
+ bool *qual_ok);
+static ScanKey _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys);
+static void _bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap);
+static Datum _bt_find_extreme_element(IndexScanDesc scan, ScanKey skey,
+ Oid elemtype, StrategyNumber strat,
+ Datum *elems, int nelems);
+static void _bt_setup_array_cmp(IndexScanDesc scan, ScanKey skey, Oid elemtype,
+ FmgrInfo *orderproc, FmgrInfo **sortprocp);
+static int _bt_sort_array_elements(ScanKey skey, FmgrInfo *sortproc,
+ bool reverse, Datum *elems, int nelems);
+static bool _bt_merge_arrays(IndexScanDesc scan, ScanKey skey,
+ FmgrInfo *sortproc, bool reverse,
+ Oid origelemtype, Oid nextelemtype,
+ Datum *elems_orig, int *nelems_orig,
+ Datum *elems_next, int nelems_next);
+static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
+
+
+/*
+ * _bt_preprocess_keys() -- Preprocess scan keys
+ *
+ * The given search-type keys (taken from scan->keyData[])
+ * are copied to so->keyData[] with possible transformation.
+ * scan->numberOfKeys is the number of input keys, so->numberOfKeys gets
+ * the number of output keys. Calling here a second or subsequent time
+ * (during the same btrescan) is a no-op.
+ *
+ * The output keys are marked with additional sk_flags bits beyond the
+ * system-standard bits supplied by the caller. The DESC and NULLS_FIRST
+ * indoption bits for the relevant index attribute are copied into the flags.
+ * Also, for a DESC column, we commute (flip) all the sk_strategy numbers
+ * so that the index sorts in the desired direction.
+ *
+ * One key purpose of this routine is to discover which scan keys must be
+ * satisfied to continue the scan. It also attempts to eliminate redundant
+ * keys and detect contradictory keys. (If the index opfamily provides
+ * incomplete sets of cross-type operators, we may fail to detect redundant
+ * or contradictory keys, but we can survive that.)
+ *
+ * The output keys must be sorted by index attribute. Presently we expect
+ * (but verify) that the input keys are already so sorted --- this is done
+ * by match_clauses_to_index() in indxpath.c. Some reordering of the keys
+ * within each attribute may be done as a byproduct of the processing here.
+ * That process must leave array scan keys (within an attribute) in the same
+ * order as corresponding entries from the scan's BTArrayKeyInfo array info.
+ *
+ * The output keys are marked with flags SK_BT_REQFWD and/or SK_BT_REQBKWD
+ * if they must be satisfied in order to continue the scan forward or backward
+ * respectively. _bt_checkkeys uses these flags. For example, if the quals
+ * are "x = 1 AND y < 4 AND z < 5", then _bt_checkkeys will reject a tuple
+ * (1,2,7), but we must continue the scan in case there are tuples (1,3,z).
+ * But once we reach tuples like (1,4,z) we can stop scanning because no
+ * later tuples could match. This is reflected by marking the x and y keys,
+ * but not the z key, with SK_BT_REQFWD. In general, the keys for leading
+ * attributes with "=" keys are marked both SK_BT_REQFWD and SK_BT_REQBKWD.
+ * For the first attribute without an "=" key, any "<" and "<=" keys are
+ * marked SK_BT_REQFWD while any ">" and ">=" keys are marked SK_BT_REQBKWD.
+ * This can be seen to be correct by considering the above example. Note
+ * in particular that if there are no keys for a given attribute, the keys for
+ * subsequent attributes can never be required; for instance "WHERE y = 4"
+ * requires a full-index scan.
+ *
+ * If possible, redundant keys are eliminated: we keep only the tightest
+ * >/>= bound and the tightest </<= bound, and if there's an = key then
+ * that's the only one returned. (So, we return either a single = key,
+ * or one or two boundary-condition keys for each attr.) However, if we
+ * cannot compare two keys for lack of a suitable cross-type operator,
+ * we cannot eliminate either. If there are two such keys of the same
+ * operator strategy, the second one is just pushed into the output array
+ * without further processing here. We may also emit both >/>= or both
+ * </<= keys if we can't compare them. The logic about required keys still
+ * works if we don't eliminate redundant keys.
+ *
+ * Note that one reason we need direction-sensitive required-key flags is
+ * precisely that we may not be able to eliminate redundant keys. Suppose
+ * we have "x > 4::int AND x > 10::bigint", and we are unable to determine
+ * which key is more restrictive for lack of a suitable cross-type operator.
+ * _bt_first will arbitrarily pick one of the keys to do the initial
+ * positioning with. If it picks x > 4, then the x > 10 condition will fail
+ * until we reach index entries > 10; but we can't stop the scan just because
+ * x > 10 is failing. On the other hand, if we are scanning backwards, then
+ * failure of either key is indeed enough to stop the scan. (In general, when
+ * inequality keys are present, the initial-positioning code only promises to
+ * position before the first possible match, not exactly at the first match,
+ * for a forward scan; or after the last match for a backward scan.)
+ *
+ * As a byproduct of this work, we can detect contradictory quals such
+ * as "x = 1 AND x > 2". If we see that, we return so->qual_ok = false,
+ * indicating the scan need not be run at all since no tuples can match.
+ * (In this case we do not bother completing the output key array!)
+ * Again, missing cross-type operators might cause us to fail to prove the
+ * quals contradictory when they really are, but the scan will work correctly.
+ *
+ * Row comparison keys are currently also treated without any smarts:
+ * we just transfer them into the preprocessed array without any
+ * editorialization. We can treat them the same as an ordinary inequality
+ * comparison on the row's first index column, for the purposes of the logic
+ * about required keys.
+ *
+ * Note: the reason we have to copy the preprocessed scan keys into private
+ * storage is that we are modifying the array based on comparisons of the
+ * key argument values, which could change on a rescan. Therefore we can't
+ * overwrite the source data.
+ */
+void
+_bt_preprocess_keys(IndexScanDesc scan)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ int numberOfKeys = scan->numberOfKeys;
+ int16 *indoption = scan->indexRelation->rd_indoption;
+ int new_numberOfKeys;
+ int numberOfEqualCols;
+ ScanKey inkeys;
+ BTScanKeyPreproc xform[BTMaxStrategyNumber];
+ bool test_result;
+ AttrNumber attno;
+ ScanKey arrayKeyData;
+ int *keyDataMap = NULL;
+ int arrayidx = 0;
+
+ if (so->numberOfKeys > 0)
+ {
+ /*
+ * Only need to do preprocessing once per btrescan, at most. All
+ * calls after the first are handled as no-ops.
+ */
+ return;
+ }
+
+ /* initialize result variables */
+ so->qual_ok = true;
+ so->numberOfKeys = 0;
+
+ if (numberOfKeys < 1)
+ return; /* done if qual-less scan */
+
+ /* If any keys are SK_SEARCHARRAY type, set up array-key info */
+ arrayKeyData = _bt_preprocess_array_keys(scan, &numberOfKeys);
+ if (!so->qual_ok)
+ {
+ /* unmatchable array, so give up */
+ return;
+ }
+
+ /*
+ * Treat arrayKeyData[] (a partially preprocessed copy of scan->keyData[])
+ * as our input if _bt_preprocess_array_keys just allocated it, else just
+ * use scan->keyData[]
+ */
+ if (arrayKeyData)
+ {
+ inkeys = arrayKeyData;
+
+ /* Also maintain keyDataMap for remapping so->orderProcs[] later */
+ keyDataMap = MemoryContextAlloc(so->arrayContext,
+ numberOfKeys * sizeof(int));
+ }
+ else
+ inkeys = scan->keyData;
+
+ /* we check that input keys are correctly ordered */
+ if (inkeys[0].sk_attno < 1)
+ elog(ERROR, "btree index keys must be ordered by attribute");
+
+ /* We can short-circuit most of the work if there's just one key */
+ if (numberOfKeys == 1)
+ {
+ /* Apply indoption to scankey (might change sk_strategy!) */
+ if (!_bt_fix_scankey_strategy(&inkeys[0], indoption))
+ so->qual_ok = false;
+ memcpy(&so->keyData[0], &inkeys[0], sizeof(ScanKeyData));
+ so->numberOfKeys = 1;
+ /* We can mark the qual as required if it's for first index col */
+ if (inkeys[0].sk_attno == 1)
+ _bt_mark_scankey_required(&so->keyData[0]);
+ if (arrayKeyData)
+ {
+ /*
+ * Don't call _bt_preprocess_array_keys_final in this fast path
+ * (we'll miss out on the single value array transformation, but
+ * that's not nearly as important when there's only one scan key)
+ */
+ Assert(so->keyData[0].sk_flags & SK_SEARCHARRAY);
+ Assert(so->keyData[0].sk_strategy != BTEqualStrategyNumber ||
+ (so->arrayKeys[0].scan_key == 0 &&
+ OidIsValid(so->orderProcs[0].fn_oid)));
+ }
+
+ return;
+ }
+
+ /*
+ * Otherwise, do the full set of pushups.
+ */
+ new_numberOfKeys = 0;
+ numberOfEqualCols = 0;
+
+ /*
+ * Initialize for processing of keys for attr 1.
+ *
+ * xform[i] points to the currently best scan key of strategy type i+1; it
+ * is NULL if we haven't yet found such a key for this attr.
+ */
+ attno = 1;
+ memset(xform, 0, sizeof(xform));
+
+ /*
+ * Loop iterates from 0 to numberOfKeys inclusive; we use the last pass to
+ * handle after-last-key processing. Actual exit from the loop is at the
+ * "break" statement below.
+ */
+ for (int i = 0;; i++)
+ {
+ ScanKey inkey = inkeys + i;
+ int j;
+
+ if (i < numberOfKeys)
+ {
+ /* Apply indoption to scankey (might change sk_strategy!) */
+ if (!_bt_fix_scankey_strategy(inkey, indoption))
+ {
+ /* NULL can't be matched, so give up */
+ so->qual_ok = false;
+ return;
+ }
+ }
+
+ /*
+ * If we are at the end of the keys for a particular attr, finish up
+ * processing and emit the cleaned-up keys.
+ */
+ if (i == numberOfKeys || inkey->sk_attno != attno)
+ {
+ int priorNumberOfEqualCols = numberOfEqualCols;
+
+ /* check input keys are correctly ordered */
+ if (i < numberOfKeys && inkey->sk_attno < attno)
+ elog(ERROR, "btree index keys must be ordered by attribute");
+
+ /*
+ * If = has been specified, all other keys can be eliminated as
+ * redundant. Note that this is no less true if the = key is
+ * SEARCHARRAY; the only real difference is that the inequality
+ * key _becomes_ redundant by making _bt_compare_scankey_args
+ * eliminate the subset of elements that won't need to be matched.
+ *
+ * If we have a case like "key = 1 AND key > 2", we set qual_ok to
+ * false and abandon further processing. We'll do the same thing
+ * given a case like "key IN (0, 1) AND key > 2".
+ *
+ * We also have to deal with the case of "key IS NULL", which is
+ * unsatisfiable in combination with any other index condition. By
+ * the time we get here, that's been classified as an equality
+ * check, and we've rejected any combination of it with a regular
+ * equality condition; but not with other types of conditions.
+ */
+ if (xform[BTEqualStrategyNumber - 1].inkey)
+ {
+ ScanKey eq = xform[BTEqualStrategyNumber - 1].inkey;
+ BTArrayKeyInfo *array = NULL;
+ FmgrInfo *orderproc = NULL;
+
+ if (arrayKeyData && (eq->sk_flags & SK_SEARCHARRAY))
+ {
+ int eq_in_ikey,
+ eq_arrayidx;
+
+ eq_in_ikey = xform[BTEqualStrategyNumber - 1].inkeyi;
+ eq_arrayidx = xform[BTEqualStrategyNumber - 1].arrayidx;
+ array = &so->arrayKeys[eq_arrayidx - 1];
+ orderproc = so->orderProcs + eq_in_ikey;
+
+ Assert(array->scan_key == eq_in_ikey);
+ Assert(OidIsValid(orderproc->fn_oid));
+ }
+
+ for (j = BTMaxStrategyNumber; --j >= 0;)
+ {
+ ScanKey chk = xform[j].inkey;
+
+ if (!chk || j == (BTEqualStrategyNumber - 1))
+ continue;
+
+ if (eq->sk_flags & SK_SEARCHNULL)
+ {
+ /* IS NULL is contradictory to anything else */
+ so->qual_ok = false;
+ return;
+ }
+
+ if (_bt_compare_scankey_args(scan, chk, eq, chk,
+ array, orderproc,
+ &test_result))
+ {
+ if (!test_result)
+ {
+ /* keys proven mutually contradictory */
+ so->qual_ok = false;
+ return;
+ }
+ /* else discard the redundant non-equality key */
+ Assert(!array || array->num_elems > 0);
+ xform[j].inkey = NULL;
+ xform[j].inkeyi = -1;
+ }
+ /* else, cannot determine redundancy, keep both keys */
+ }
+ /* track number of attrs for which we have "=" keys */
+ numberOfEqualCols++;
+ }
+
+ /* try to keep only one of <, <= */
+ if (xform[BTLessStrategyNumber - 1].inkey &&
+ xform[BTLessEqualStrategyNumber - 1].inkey)
+ {
+ ScanKey lt = xform[BTLessStrategyNumber - 1].inkey;
+ ScanKey le = xform[BTLessEqualStrategyNumber - 1].inkey;
+
+ if (_bt_compare_scankey_args(scan, le, lt, le, NULL, NULL,
+ &test_result))
+ {
+ if (test_result)
+ xform[BTLessEqualStrategyNumber - 1].inkey = NULL;
+ else
+ xform[BTLessStrategyNumber - 1].inkey = NULL;
+ }
+ }
+
+ /* try to keep only one of >, >= */
+ if (xform[BTGreaterStrategyNumber - 1].inkey &&
+ xform[BTGreaterEqualStrategyNumber - 1].inkey)
+ {
+ ScanKey gt = xform[BTGreaterStrategyNumber - 1].inkey;
+ ScanKey ge = xform[BTGreaterEqualStrategyNumber - 1].inkey;
+
+ if (_bt_compare_scankey_args(scan, ge, gt, ge, NULL, NULL,
+ &test_result))
+ {
+ if (test_result)
+ xform[BTGreaterEqualStrategyNumber - 1].inkey = NULL;
+ else
+ xform[BTGreaterStrategyNumber - 1].inkey = NULL;
+ }
+ }
+
+ /*
+ * Emit the cleaned-up keys into the so->keyData[] array, and then
+ * mark them if they are required. They are required (possibly
+ * only in one direction) if all attrs before this one had "=".
+ */
+ for (j = BTMaxStrategyNumber; --j >= 0;)
+ {
+ if (xform[j].inkey)
+ {
+ ScanKey outkey = &so->keyData[new_numberOfKeys++];
+
+ memcpy(outkey, xform[j].inkey, sizeof(ScanKeyData));
+ if (arrayKeyData)
+ keyDataMap[new_numberOfKeys - 1] = xform[j].inkeyi;
+ if (priorNumberOfEqualCols == attno - 1)
+ _bt_mark_scankey_required(outkey);
+ }
+ }
+
+ /*
+ * Exit loop here if done.
+ */
+ if (i == numberOfKeys)
+ break;
+
+ /* Re-initialize for new attno */
+ attno = inkey->sk_attno;
+ memset(xform, 0, sizeof(xform));
+ }
+
+ /* check strategy this key's operator corresponds to */
+ j = inkey->sk_strategy - 1;
+
+ /* if row comparison, push it directly to the output array */
+ if (inkey->sk_flags & SK_ROW_HEADER)
+ {
+ ScanKey outkey = &so->keyData[new_numberOfKeys++];
+
+ memcpy(outkey, inkey, sizeof(ScanKeyData));
+ if (arrayKeyData)
+ keyDataMap[new_numberOfKeys - 1] = i;
+ if (numberOfEqualCols == attno - 1)
+ _bt_mark_scankey_required(outkey);
+
+ /*
+ * We don't support RowCompare using equality; such a qual would
+ * mess up the numberOfEqualCols tracking.
+ */
+ Assert(j != (BTEqualStrategyNumber - 1));
+ continue;
+ }
+
+ if (inkey->sk_strategy == BTEqualStrategyNumber &&
+ (inkey->sk_flags & SK_SEARCHARRAY))
+ {
+ /* must track how input scan keys map to arrays */
+ Assert(arrayKeyData);
+ arrayidx++;
+ }
+
+ /*
+ * have we seen a scan key for this same attribute and using this same
+ * operator strategy before now?
+ */
+ if (xform[j].inkey == NULL)
+ {
+ /* nope, so this scan key wins by default (at least for now) */
+ xform[j].inkey = inkey;
+ xform[j].inkeyi = i;
+ xform[j].arrayidx = arrayidx;
+ }
+ else
+ {
+ FmgrInfo *orderproc = NULL;
+ BTArrayKeyInfo *array = NULL;
+
+ /*
+ * Seen one of these before, so keep only the more restrictive key
+ * if possible
+ */
+ if (j == (BTEqualStrategyNumber - 1) && arrayKeyData)
+ {
+ /*
+ * Have to set up array keys
+ */
+ if (inkey->sk_flags & SK_SEARCHARRAY)
+ {
+ array = &so->arrayKeys[arrayidx - 1];
+ orderproc = so->orderProcs + i;
+
+ Assert(array->scan_key == i);
+ Assert(OidIsValid(orderproc->fn_oid));
+ }
+ else if (xform[j].inkey->sk_flags & SK_SEARCHARRAY)
+ {
+ array = &so->arrayKeys[xform[j].arrayidx - 1];
+ orderproc = so->orderProcs + xform[j].inkeyi;
+
+ Assert(array->scan_key == xform[j].inkeyi);
+ Assert(OidIsValid(orderproc->fn_oid));
+ }
+
+ /*
+ * Both scan keys might have arrays, in which case we'll
+ * arbitrarily pass only one of the arrays. That won't
+ * matter, since _bt_compare_scankey_args is aware that two
+ * SEARCHARRAY scan keys mean that _bt_preprocess_array_keys
+ * failed to eliminate redundant arrays through array merging.
+ * _bt_compare_scankey_args just returns false when it sees
+ * this; it won't even try to examine either array.
+ */
+ }
+
+ if (_bt_compare_scankey_args(scan, inkey, inkey, xform[j].inkey,
+ array, orderproc, &test_result))
+ {
+ /* Have all we need to determine redundancy */
+ if (test_result)
+ {
+ Assert(!array || array->num_elems > 0);
+
+ /*
+ * New key is more restrictive, and so replaces old key...
+ */
+ if (j != (BTEqualStrategyNumber - 1) ||
+ !(xform[j].inkey->sk_flags & SK_SEARCHARRAY))
+ {
+ xform[j].inkey = inkey;
+ xform[j].inkeyi = i;
+ xform[j].arrayidx = arrayidx;
+ }
+ else
+ {
+ /*
+ * ...unless we have to keep the old key because it's
+ * an array that rendered the new key redundant. We
+ * need to make sure that we don't throw away an array
+ * scan key. _bt_preprocess_array_keys_final expects
+ * us to keep all of the arrays that weren't already
+ * eliminated by _bt_preprocess_array_keys earlier on.
+ */
+ Assert(!(inkey->sk_flags & SK_SEARCHARRAY));
+ }
+ }
+ else if (j == (BTEqualStrategyNumber - 1))
+ {
+ /* key == a && key == b, but a != b */
+ so->qual_ok = false;
+ return;
+ }
+ /* else old key is more restrictive, keep it */
+ }
+ else
+ {
+ /*
+ * We can't determine which key is more restrictive. Push
+ * xform[j] directly to the output array, then set xform[j] to
+ * the new scan key.
+ *
+ * Note: We do things this way around so that our arrays are
+ * always in the same order as their corresponding scan keys,
+ * even with incomplete opfamilies. _bt_advance_array_keys
+ * depends on this.
+ */
+ ScanKey outkey = &so->keyData[new_numberOfKeys++];
+
+ memcpy(outkey, xform[j].inkey, sizeof(ScanKeyData));
+ if (arrayKeyData)
+ keyDataMap[new_numberOfKeys - 1] = xform[j].inkeyi;
+ if (numberOfEqualCols == attno - 1)
+ _bt_mark_scankey_required(outkey);
+ xform[j].inkey = inkey;
+ xform[j].inkeyi = i;
+ xform[j].arrayidx = arrayidx;
+ }
+ }
+ }
+
+ so->numberOfKeys = new_numberOfKeys;
+
+ /*
+ * Now that we've built a temporary mapping from so->keyData[] (output
+ * scan keys) to arrayKeyData[] (our input scan keys), fix array->scan_key
+ * references. Also consolidate the so->orderProcs[] array such that it
+ * can be subscripted using so->keyData[]-wise offsets.
+ */
+ if (arrayKeyData)
+ _bt_preprocess_array_keys_final(scan, keyDataMap);
+
+ /* Could pfree arrayKeyData/keyDataMap now, but not worth the cycles */
+}
+
+/*
+ * Adjust a scankey's strategy and flags setting as needed for indoptions.
+ *
+ * We copy the appropriate indoption value into the scankey sk_flags
+ * (shifting to avoid clobbering system-defined flag bits). Also, if
+ * the DESC option is set, commute (flip) the operator strategy number.
+ *
+ * A secondary purpose is to check for IS NULL/NOT NULL scankeys and set up
+ * the strategy field correctly for them.
+ *
+ * Lastly, for ordinary scankeys (not IS NULL/NOT NULL), we check for a
+ * NULL comparison value. Since all btree operators are assumed strict,
+ * a NULL means that the qual cannot be satisfied. We return true if the
+ * comparison value isn't NULL, or false if the scan should be abandoned.
+ *
+ * This function is applied to the *input* scankey structure; therefore
+ * on a rescan we will be looking at already-processed scankeys. Hence
+ * we have to be careful not to re-commute the strategy if we already did it.
+ * It's a bit ugly to modify the caller's copy of the scankey but in practice
+ * there shouldn't be any problem, since the index's indoptions are certainly
+ * not going to change while the scankey survives.
+ */
+static bool
+_bt_fix_scankey_strategy(ScanKey skey, int16 *indoption)
+{
+ int addflags;
+
+ addflags = indoption[skey->sk_attno - 1] << SK_BT_INDOPTION_SHIFT;
+
+ /*
+ * We treat all btree operators as strict (even if they're not so marked
+ * in pg_proc). This means that it is impossible for an operator condition
+ * with a NULL comparison constant to succeed, and we can reject it right
+ * away.
+ *
+ * However, we now also support "x IS NULL" clauses as search conditions,
+ * so in that case keep going. The planner has not filled in any
+ * particular strategy in this case, so set it to BTEqualStrategyNumber
+ * --- we can treat IS NULL as an equality operator for purposes of search
+ * strategy.
+ *
+ * Likewise, "x IS NOT NULL" is supported. We treat that as either "less
+ * than NULL" in a NULLS LAST index, or "greater than NULL" in a NULLS
+ * FIRST index.
+ *
+ * Note: someday we might have to fill in sk_collation from the index
+ * column's collation. At the moment this is a non-issue because we'll
+ * never actually call the comparison operator on a NULL.
+ */
+ if (skey->sk_flags & SK_ISNULL)
+ {
+ /* SK_ISNULL shouldn't be set in a row header scankey */
+ Assert(!(skey->sk_flags & SK_ROW_HEADER));
+
+ /* Set indoption flags in scankey (might be done already) */
+ skey->sk_flags |= addflags;
+
+ /* Set correct strategy for IS NULL or NOT NULL search */
+ if (skey->sk_flags & SK_SEARCHNULL)
+ {
+ skey->sk_strategy = BTEqualStrategyNumber;
+ skey->sk_subtype = InvalidOid;
+ skey->sk_collation = InvalidOid;
+ }
+ else if (skey->sk_flags & SK_SEARCHNOTNULL)
+ {
+ if (skey->sk_flags & SK_BT_NULLS_FIRST)
+ skey->sk_strategy = BTGreaterStrategyNumber;
+ else
+ skey->sk_strategy = BTLessStrategyNumber;
+ skey->sk_subtype = InvalidOid;
+ skey->sk_collation = InvalidOid;
+ }
+ else
+ {
+ /* regular qual, so it cannot be satisfied */
+ return false;
+ }
+
+ /* Needn't do the rest */
+ return true;
+ }
+
+ /* Adjust strategy for DESC, if we didn't already */
+ if ((addflags & SK_BT_DESC) && !(skey->sk_flags & SK_BT_DESC))
+ skey->sk_strategy = BTCommuteStrategyNumber(skey->sk_strategy);
+ skey->sk_flags |= addflags;
+
+ /* If it's a row header, fix row member flags and strategies similarly */
+ if (skey->sk_flags & SK_ROW_HEADER)
+ {
+ ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
+
+ if (subkey->sk_flags & SK_ISNULL)
+ {
+ /* First row member is NULL, so RowCompare is unsatisfiable */
+ Assert(subkey->sk_flags & SK_ROW_MEMBER);
+ return false;
+ }
+
+ for (;;)
+ {
+ Assert(subkey->sk_flags & SK_ROW_MEMBER);
+ addflags = indoption[subkey->sk_attno - 1] << SK_BT_INDOPTION_SHIFT;
+ if ((addflags & SK_BT_DESC) && !(subkey->sk_flags & SK_BT_DESC))
+ subkey->sk_strategy = BTCommuteStrategyNumber(subkey->sk_strategy);
+ subkey->sk_flags |= addflags;
+ if (subkey->sk_flags & SK_ROW_END)
+ break;
+ subkey++;
+ }
+ }
+
+ return true;
+}
+
+/*
+ * Mark a scankey as "required to continue the scan".
+ *
+ * Depending on the operator type, the key may be required for both scan
+ * directions or just one. Also, if the key is a row comparison header,
+ * we have to mark its first subsidiary ScanKey as required. (Subsequent
+ * subsidiary ScanKeys are normally for lower-order columns, and thus
+ * cannot be required, since they're after the first non-equality scankey.)
+ *
+ * Note: when we set required-key flag bits in a subsidiary scankey, we are
+ * scribbling on a data structure belonging to the index AM's caller, not on
+ * our private copy. This should be OK because the marking will not change
+ * from scan to scan within a query, and so we'd just re-mark the same way
+ * anyway on a rescan. Something to keep an eye on though.
+ */
+static void
+_bt_mark_scankey_required(ScanKey skey)
+{
+ int addflags;
+
+ switch (skey->sk_strategy)
+ {
+ case BTLessStrategyNumber:
+ case BTLessEqualStrategyNumber:
+ addflags = SK_BT_REQFWD;
+ break;
+ case BTEqualStrategyNumber:
+ addflags = SK_BT_REQFWD | SK_BT_REQBKWD;
+ break;
+ case BTGreaterEqualStrategyNumber:
+ case BTGreaterStrategyNumber:
+ addflags = SK_BT_REQBKWD;
+ break;
+ default:
+ elog(ERROR, "unrecognized StrategyNumber: %d",
+ (int) skey->sk_strategy);
+ addflags = 0; /* keep compiler quiet */
+ break;
+ }
+
+ skey->sk_flags |= addflags;
+
+ if (skey->sk_flags & SK_ROW_HEADER)
+ {
+ ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
+
+ /* First subkey should be same column/operator as the header */
+ Assert(subkey->sk_flags & SK_ROW_MEMBER);
+ Assert(subkey->sk_attno == skey->sk_attno);
+ Assert(subkey->sk_strategy == skey->sk_strategy);
+ subkey->sk_flags |= addflags;
+ }
+}
+
+/*
+ * Compare two scankey values using a specified operator.
+ *
+ * The test we want to perform is logically "leftarg op rightarg", where
+ * leftarg and rightarg are the sk_argument values in those ScanKeys, and
+ * the comparison operator is the one in the op ScanKey. However, in
+ * cross-data-type situations we may need to look up the correct operator in
+ * the index's opfamily: it is the one having amopstrategy = op->sk_strategy
+ * and amoplefttype/amoprighttype equal to the two argument datatypes.
+ *
+ * If the opfamily doesn't supply a complete set of cross-type operators we
+ * may not be able to make the comparison. If we can make the comparison
+ * we store the operator result in *result and return true. We return false
+ * if the comparison could not be made.
+ *
+ * If either leftarg or rightarg are an array, we'll apply array-specific
+ * rules to determine which array elements are redundant on behalf of caller.
+ * It is up to our caller to save whichever of the two scan keys is the array,
+ * and discard the non-array scan key (the non-array scan key is guaranteed to
+ * be redundant with any complete opfamily). Caller isn't expected to call
+ * here with a pair of array scan keys provided we're dealing with a complete
+ * opfamily (_bt_preprocess_array_keys will merge array keys together to make
+ * sure of that).
+ *
+ * Note: we'll also shrink caller's array as needed to eliminate redundant
+ * array elements. One reason why caller should prefer to discard non-array
+ * scan keys is so that we'll have the opportunity to shrink the array
+ * multiple times, in multiple calls (for each of several other scan keys on
+ * the same index attribute).
+ *
+ * Note: op always points at the same ScanKey as either leftarg or rightarg.
+ * Since we don't scribble on the scankeys themselves, this aliasing should
+ * cause no trouble.
+ *
+ * Note: this routine needs to be insensitive to any DESC option applied
+ * to the index column. For example, "x < 4" is a tighter constraint than
+ * "x < 5" regardless of which way the index is sorted.
+ */
+static bool
+_bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
+ ScanKey leftarg, ScanKey rightarg,
+ BTArrayKeyInfo *array, FmgrInfo *orderproc,
+ bool *result)
+{
+ Relation rel = scan->indexRelation;
+ Oid lefttype,
+ righttype,
+ optype,
+ opcintype,
+ cmp_op;
+ StrategyNumber strat;
+
+ /*
+ * First, deal with cases where one or both args are NULL. This should
+ * only happen when the scankeys represent IS NULL/NOT NULL conditions.
+ */
+ if ((leftarg->sk_flags | rightarg->sk_flags) & SK_ISNULL)
+ {
+ bool leftnull,
+ rightnull;
+
+ if (leftarg->sk_flags & SK_ISNULL)
+ {
+ Assert(leftarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
+ leftnull = true;
+ }
+ else
+ leftnull = false;
+ if (rightarg->sk_flags & SK_ISNULL)
+ {
+ Assert(rightarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
+ rightnull = true;
+ }
+ else
+ rightnull = false;
+
+ /*
+ * We treat NULL as either greater than or less than all other values.
+ * Since true > false, the tests below work correctly for NULLS LAST
+ * logic. If the index is NULLS FIRST, we need to flip the strategy.
+ */
+ strat = op->sk_strategy;
+ if (op->sk_flags & SK_BT_NULLS_FIRST)
+ strat = BTCommuteStrategyNumber(strat);
+
+ switch (strat)
+ {
+ case BTLessStrategyNumber:
+ *result = (leftnull < rightnull);
+ break;
+ case BTLessEqualStrategyNumber:
+ *result = (leftnull <= rightnull);
+ break;
+ case BTEqualStrategyNumber:
+ *result = (leftnull == rightnull);
+ break;
+ case BTGreaterEqualStrategyNumber:
+ *result = (leftnull >= rightnull);
+ break;
+ case BTGreaterStrategyNumber:
+ *result = (leftnull > rightnull);
+ break;
+ default:
+ elog(ERROR, "unrecognized StrategyNumber: %d", (int) strat);
+ *result = false; /* keep compiler quiet */
+ break;
+ }
+ return true;
+ }
+
+ /*
+ * If either leftarg or rightarg are equality-type array scankeys, we need
+ * specialized handling (since by now we know that IS NULL wasn't used)
+ */
+ if (array)
+ {
+ bool leftarray,
+ rightarray;
+
+ leftarray = ((leftarg->sk_flags & SK_SEARCHARRAY) &&
+ leftarg->sk_strategy == BTEqualStrategyNumber);
+ rightarray = ((rightarg->sk_flags & SK_SEARCHARRAY) &&
+ rightarg->sk_strategy == BTEqualStrategyNumber);
+
+ /*
+ * _bt_preprocess_array_keys is responsible for merging together array
+ * scan keys, and will do so whenever the opfamily has the required
+ * cross-type support. If it failed to do that, we handle it just
+ * like the case where we can't make the comparison ourselves.
+ */
+ if (leftarray && rightarray)
+ {
+ /* Can't make the comparison */
+ *result = false; /* suppress compiler warnings */
+ return false;
+ }
+
+ /*
+ * Otherwise we need to determine if either one of leftarg or rightarg
+ * uses an array, then pass this through to a dedicated helper
+ * function.
+ */
+ if (leftarray)
+ return _bt_compare_array_scankey_args(scan, leftarg, rightarg,
+ orderproc, array, result);
+ else if (rightarray)
+ return _bt_compare_array_scankey_args(scan, rightarg, leftarg,
+ orderproc, array, result);
+
+ /* FALL THRU */
+ }
+
+ /*
+ * The opfamily we need to worry about is identified by the index column.
+ */
+ Assert(leftarg->sk_attno == rightarg->sk_attno);
+
+ opcintype = rel->rd_opcintype[leftarg->sk_attno - 1];
+
+ /*
+ * Determine the actual datatypes of the ScanKey arguments. We have to
+ * support the convention that sk_subtype == InvalidOid means the opclass
+ * input type; this is a hack to simplify life for ScanKeyInit().
+ */
+ lefttype = leftarg->sk_subtype;
+ if (lefttype == InvalidOid)
+ lefttype = opcintype;
+ righttype = rightarg->sk_subtype;
+ if (righttype == InvalidOid)
+ righttype = opcintype;
+ optype = op->sk_subtype;
+ if (optype == InvalidOid)
+ optype = opcintype;
+
+ /*
+ * If leftarg and rightarg match the types expected for the "op" scankey,
+ * we can use its already-looked-up comparison function.
+ */
+ if (lefttype == opcintype && righttype == optype)
+ {
+ *result = DatumGetBool(FunctionCall2Coll(&op->sk_func,
+ op->sk_collation,
+ leftarg->sk_argument,
+ rightarg->sk_argument));
+ return true;
+ }
+
+ /*
+ * Otherwise, we need to go to the syscache to find the appropriate
+ * operator. (This cannot result in infinite recursion, since no
+ * indexscan initiated by syscache lookup will use cross-data-type
+ * operators.)
+ *
+ * If the sk_strategy was flipped by _bt_fix_scankey_strategy, we have to
+ * un-flip it to get the correct opfamily member.
+ */
+ strat = op->sk_strategy;
+ if (op->sk_flags & SK_BT_DESC)
+ strat = BTCommuteStrategyNumber(strat);
+
+ cmp_op = get_opfamily_member(rel->rd_opfamily[leftarg->sk_attno - 1],
+ lefttype,
+ righttype,
+ strat);
+ if (OidIsValid(cmp_op))
+ {
+ RegProcedure cmp_proc = get_opcode(cmp_op);
+
+ if (RegProcedureIsValid(cmp_proc))
+ {
+ *result = DatumGetBool(OidFunctionCall2Coll(cmp_proc,
+ op->sk_collation,
+ leftarg->sk_argument,
+ rightarg->sk_argument));
+ return true;
+ }
+ }
+
+ /* Can't make the comparison */
+ *result = false; /* suppress compiler warnings */
+ return false;
+}
+
+/*
+ * Compare an array scan key to a scalar scan key, eliminating contradictory
+ * array elements such that the scalar scan key becomes redundant.
+ *
+ * Array elements can be eliminated as contradictory when excluded by some
+ * other operator on the same attribute. For example, with an index scan qual
+ * "WHERE a IN (1, 2, 3) AND a < 2", all array elements except the value "1"
+ * are eliminated, and the < scan key is eliminated as redundant. Cases where
+ * every array element is eliminated by a redundant scalar scan key have an
+ * unsatisfiable qual, which we handle by setting *qual_ok=false for caller.
+ *
+ * If the opfamily doesn't supply a complete set of cross-type ORDER procs we
+ * may not be able to determine which elements are contradictory. If we have
+ * the required ORDER proc then we return true (and validly set *qual_ok),
+ * guaranteeing that at least the scalar scan key can be considered redundant.
+ * We return false if the comparison could not be made (caller must keep both
+ * scan keys when this happens).
+ */
+static bool
+_bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey,
+ FmgrInfo *orderproc, BTArrayKeyInfo *array,
+ bool *qual_ok)
+{
+ Relation rel = scan->indexRelation;
+ Oid opcintype = rel->rd_opcintype[arraysk->sk_attno - 1];
+ int cmpresult = 0,
+ cmpexact = 0,
+ matchelem,
+ new_nelems = 0;
+ FmgrInfo crosstypeproc;
+ FmgrInfo *orderprocp = orderproc;
+
+ Assert(arraysk->sk_attno == skey->sk_attno);
+ Assert(array->num_elems > 0);
+ Assert(!(arraysk->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
+ Assert((arraysk->sk_flags & SK_SEARCHARRAY) &&
+ arraysk->sk_strategy == BTEqualStrategyNumber);
+ Assert(!(skey->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
+ Assert(!(skey->sk_flags & SK_SEARCHARRAY) ||
+ skey->sk_strategy != BTEqualStrategyNumber);
+
+ /*
+ * _bt_binsrch_array_skey searches an array for the entry best matching a
+ * datum of opclass input type for the index's attribute (on-disk type).
+ * We can reuse the array's ORDER proc whenever the non-array scan key's
+ * type is a match for the corresponding attribute's input opclass type.
+ * Otherwise, we have to do another ORDER proc lookup so that our call to
+ * _bt_binsrch_array_skey applies the correct comparator.
+ *
+ * Note: we have to support the convention that sk_subtype == InvalidOid
+ * means the opclass input type; this is a hack to simplify life for
+ * ScanKeyInit().
+ */
+ if (skey->sk_subtype != opcintype && skey->sk_subtype != InvalidOid)
+ {
+ RegProcedure cmp_proc;
+ Oid arraysk_elemtype;
+
+ /*
+ * Need an ORDER proc lookup to detect redundancy/contradictoriness
+ * with this pair of scankeys.
+ *
+ * Scalar scan key's argument will be passed to _bt_compare_array_skey
+ * as its tupdatum/lefthand argument (rhs arg is for array elements).
+ */
+ arraysk_elemtype = arraysk->sk_subtype;
+ if (arraysk_elemtype == InvalidOid)
+ arraysk_elemtype = rel->rd_opcintype[arraysk->sk_attno - 1];
+ cmp_proc = get_opfamily_proc(rel->rd_opfamily[arraysk->sk_attno - 1],
+ skey->sk_subtype, arraysk_elemtype,
+ BTORDER_PROC);
+ if (!RegProcedureIsValid(cmp_proc))
+ {
+ /* Can't make the comparison */
+ *qual_ok = false; /* suppress compiler warnings */
+ return false;
+ }
+
+ /* We have all we need to determine redundancy/contradictoriness */
+ orderprocp = &crosstypeproc;
+ fmgr_info(cmp_proc, orderprocp);
+ }
+
+ matchelem = _bt_binsrch_array_skey(orderprocp, false,
+ NoMovementScanDirection,
+ skey->sk_argument, false, array,
+ arraysk, &cmpresult);
+
+ switch (skey->sk_strategy)
+ {
+ case BTLessStrategyNumber:
+ cmpexact = 1; /* exclude exact match, if any */
+ /* FALL THRU */
+ case BTLessEqualStrategyNumber:
+ if (cmpresult >= cmpexact)
+ matchelem++;
+ /* Resize, keeping elements from the start of the array */
+ new_nelems = matchelem;
+ break;
+ case BTEqualStrategyNumber:
+ if (cmpresult != 0)
+ {
+ /* qual is unsatisfiable */
+ new_nelems = 0;
+ }
+ else
+ {
+ /* Shift matching element to the start of the array, resize */
+ array->elem_values[0] = array->elem_values[matchelem];
+ new_nelems = 1;
+ }
+ break;
+ case BTGreaterEqualStrategyNumber:
+ cmpexact = 1; /* include exact match, if any */
+ /* FALL THRU */
+ case BTGreaterStrategyNumber:
+ if (cmpresult >= cmpexact)
+ matchelem++;
+ /* Shift matching elements to the start of the array, resize */
+ new_nelems = array->num_elems - matchelem;
+ memmove(array->elem_values, array->elem_values + matchelem,
+ sizeof(Datum) * new_nelems);
+ break;
+ default:
+ elog(ERROR, "unrecognized StrategyNumber: %d",
+ (int) skey->sk_strategy);
+ break;
+ }
+
+ Assert(new_nelems >= 0);
+ Assert(new_nelems <= array->num_elems);
+
+ array->num_elems = new_nelems;
+ *qual_ok = new_nelems > 0;
+
+ return true;
+}
+
+/*
+ * _bt_preprocess_array_keys() -- Preprocess SK_SEARCHARRAY scan keys
+ *
+ * If there are any SK_SEARCHARRAY scan keys, deconstruct the array(s) and
+ * set up BTArrayKeyInfo info for each one that is an equality-type key.
+ * Returns modified scan keys as input for further, standard preprocessing.
+ *
+ * Currently we perform two kinds of preprocessing to deal with redundancies.
+ * For inequality array keys, it's sufficient to find the extreme element
+ * value and replace the whole array with that scalar value. This eliminates
+ * all but one array element as redundant. Similarly, we are capable of
+ * "merging together" multiple equality array keys (from two or more input
+ * scan keys) into a single output scan key containing only the intersecting
+ * array elements. This can eliminate many redundant array elements, as well
+ * as eliminating whole array scan keys as redundant. It can also allow us to
+ * detect contradictory quals.
+ *
+ * Caller must pass *new_numberOfKeys to give us a way to change the number of
+ * scan keys that caller treats as input to standard preprocessing steps. The
+ * returned array is smaller than scan->keyData[] when we could eliminate a
+ * redundant array scan key (redundant with another array scan key). It is
+ * convenient for _bt_preprocess_keys caller to have to deal with no more than
+ * one equality strategy array scan key per index attribute. We'll always be
+ * able to set things up that way when complete opfamilies are used.
+ *
+ * We set the scan key references from the scan's BTArrayKeyInfo info array to
+ * offsets into the temp modified input array returned to caller. Scans that
+ * have array keys should call _bt_preprocess_array_keys_final when standard
+ * preprocessing steps are complete. This will convert the scan key offset
+ * references into references to the scan's so->keyData[] output scan keys.
+ *
+ * Note: the reason we need to return a temp scan key array, rather than just
+ * scribbling on scan->keyData, is that callers are permitted to call btrescan
+ * without supplying a new set of scankey data.
+ */
+static ScanKey
+_bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ Relation rel = scan->indexRelation;
+ int numberOfKeys = scan->numberOfKeys;
+ int16 *indoption = rel->rd_indoption;
+ int numArrayKeys,
+ output_ikey = 0;
+ int origarrayatt = InvalidAttrNumber,
+ origarraykey = -1;
+ Oid origelemtype = InvalidOid;
+ ScanKey cur;
+ MemoryContext oldContext;
+ ScanKey arrayKeyData; /* modified copy of scan->keyData */
+
+ Assert(numberOfKeys);
+
+ /* Quick check to see if there are any array keys */
+ numArrayKeys = 0;
+ for (int i = 0; i < numberOfKeys; i++)
+ {
+ cur = &scan->keyData[i];
+ if (cur->sk_flags & SK_SEARCHARRAY)
+ {
+ numArrayKeys++;
+ Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
+ /* If any arrays are null as a whole, we can quit right now. */
+ if (cur->sk_flags & SK_ISNULL)
+ {
+ so->qual_ok = false;
+ return NULL;
+ }
+ }
+ }
+
+ /* Quit if nothing to do. */
+ if (numArrayKeys == 0)
+ return NULL;
+
+ /*
+ * Make a scan-lifespan context to hold array-associated data, or reset it
+ * if we already have one from a previous rescan cycle.
+ */
+ if (so->arrayContext == NULL)
+ so->arrayContext = AllocSetContextCreate(CurrentMemoryContext,
+ "BTree array context",
+ ALLOCSET_SMALL_SIZES);
+ else
+ MemoryContextReset(so->arrayContext);
+
+ oldContext = MemoryContextSwitchTo(so->arrayContext);
+
+ /* Create output scan keys in the workspace context */
+ arrayKeyData = (ScanKey) palloc(numberOfKeys * sizeof(ScanKeyData));
+
+ /* Allocate space for per-array data in the workspace context */
+ so->arrayKeys = (BTArrayKeyInfo *) palloc(numArrayKeys * sizeof(BTArrayKeyInfo));
+
+ /* Allocate space for ORDER procs used to help _bt_checkkeys */
+ so->orderProcs = (FmgrInfo *) palloc(numberOfKeys * sizeof(FmgrInfo));
+
+ /* Now process each array key */
+ numArrayKeys = 0;
+ for (int input_ikey = 0; input_ikey < numberOfKeys; input_ikey++)
+ {
+ FmgrInfo sortproc;
+ FmgrInfo *sortprocp = &sortproc;
+ Oid elemtype;
+ bool reverse;
+ ArrayType *arrayval;
+ int16 elmlen;
+ bool elmbyval;
+ char elmalign;
+ int num_elems;
+ Datum *elem_values;
+ bool *elem_nulls;
+ int num_nonnulls;
+ int j;
+
+ /*
+ * Provisionally copy scan key into arrayKeyData[] array we'll return
+ * to _bt_preprocess_keys caller
+ */
+ cur = &arrayKeyData[output_ikey];
+ *cur = scan->keyData[input_ikey];
+
+ if (!(cur->sk_flags & SK_SEARCHARRAY))
+ {
+ output_ikey++; /* keep this non-array scan key */
+ continue;
+ }
+
+ /*
+ * Deconstruct the array into elements
+ */
+ arrayval = DatumGetArrayTypeP(cur->sk_argument);
+ /* We could cache this data, but not clear it's worth it */
+ get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
+ &elmlen, &elmbyval, &elmalign);
+ deconstruct_array(arrayval,
+ ARR_ELEMTYPE(arrayval),
+ elmlen, elmbyval, elmalign,
+ &elem_values, &elem_nulls, &num_elems);
+
+ /*
+ * Compress out any null elements. We can ignore them since we assume
+ * all btree operators are strict.
+ */
+ num_nonnulls = 0;
+ for (j = 0; j < num_elems; j++)
+ {
+ if (!elem_nulls[j])
+ elem_values[num_nonnulls++] = elem_values[j];
+ }
+
+ /* We could pfree(elem_nulls) now, but not worth the cycles */
+
+ /* If there's no non-nulls, the scan qual is unsatisfiable */
+ if (num_nonnulls == 0)
+ {
+ so->qual_ok = false;
+ break;
+ }
+
+ /*
+ * Determine the nominal datatype of the array elements. We have to
+ * support the convention that sk_subtype == InvalidOid means the
+ * opclass input type; this is a hack to simplify life for
+ * ScanKeyInit().
+ */
+ elemtype = cur->sk_subtype;
+ if (elemtype == InvalidOid)
+ elemtype = rel->rd_opcintype[cur->sk_attno - 1];
+
+ /*
+ * If the comparison operator is not equality, then the array qual
+ * degenerates to a simple comparison against the smallest or largest
+ * non-null array element, as appropriate.
+ */
+ switch (cur->sk_strategy)
+ {
+ case BTLessStrategyNumber:
+ case BTLessEqualStrategyNumber:
+ cur->sk_argument =
+ _bt_find_extreme_element(scan, cur, elemtype,
+ BTGreaterStrategyNumber,
+ elem_values, num_nonnulls);
+ output_ikey++; /* keep this transformed scan key */
+ continue;
+ case BTEqualStrategyNumber:
+ /* proceed with rest of loop */
+ break;
+ case BTGreaterEqualStrategyNumber:
+ case BTGreaterStrategyNumber:
+ cur->sk_argument =
+ _bt_find_extreme_element(scan, cur, elemtype,
+ BTLessStrategyNumber,
+ elem_values, num_nonnulls);
+ output_ikey++; /* keep this transformed scan key */
+ continue;
+ default:
+ elog(ERROR, "unrecognized StrategyNumber: %d",
+ (int) cur->sk_strategy);
+ break;
+ }
+
+ /*
+ * We'll need a 3-way ORDER proc to perform binary searches for the
+ * next matching array element. Set that up now.
+ *
+ * Array scan keys with cross-type equality operators will require a
+ * separate same-type ORDER proc for sorting their array. Otherwise,
+ * sortproc just points to the same proc used during binary searches.
+ */
+ _bt_setup_array_cmp(scan, cur, elemtype,
+ &so->orderProcs[output_ikey], &sortprocp);
+
+ /*
+ * Sort the non-null elements and eliminate any duplicates. We must
+ * sort in the same ordering used by the index column, so that the
+ * arrays can be advanced in lockstep with the scan's progress through
+ * the index's key space.
+ */
+ reverse = (indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0;
+ num_elems = _bt_sort_array_elements(cur, sortprocp, reverse,
+ elem_values, num_nonnulls);
+
+ if (origarrayatt == cur->sk_attno)
+ {
+ BTArrayKeyInfo *orig = &so->arrayKeys[origarraykey];
+
+ /*
+ * This array scan key is redundant with a previous equality
+ * operator array scan key. Merge the two arrays together to
+ * eliminate contradictory non-intersecting elements (or try to).
+ *
+ * We merge this next array back into attribute's original array.
+ */
+ Assert(arrayKeyData[orig->scan_key].sk_attno == cur->sk_attno);
+ Assert(arrayKeyData[orig->scan_key].sk_collation ==
+ cur->sk_collation);
+ if (_bt_merge_arrays(scan, cur, sortprocp, reverse,
+ origelemtype, elemtype,
+ orig->elem_values, &orig->num_elems,
+ elem_values, num_elems))
+ {
+ /* Successfully eliminated this array */
+ pfree(elem_values);
+
+ /*
+ * If no intersecting elements remain in the original array,
+ * the scan qual is unsatisfiable
+ */
+ if (orig->num_elems == 0)
+ {
+ so->qual_ok = false;
+ break;
+ }
+
+ /* Throw away this scan key/array */
+ continue;
+ }
+
+ /*
+ * Unable to merge this array with previous array due to a lack of
+ * suitable cross-type opfamily support. Will need to keep both
+ * scan keys/arrays.
+ */
+ }
+ else
+ {
+ /*
+ * This array is the first for current index attribute.
+ *
+ * If it turns out to not be the last array (that is, if the next
+ * array is redundantly applied to this same index attribute),
+ * we'll then treat this array as the attribute's "original" array
+ * when merging.
+ */
+ origarrayatt = cur->sk_attno;
+ origarraykey = numArrayKeys;
+ origelemtype = elemtype;
+ }
+
+ /*
+ * And set up the BTArrayKeyInfo data.
+ *
+ * Note: _bt_preprocess_array_keys_final will fix-up each array's
+ * scan_key field later on, after so->keyData[] has been finalized.
+ */
+ so->arrayKeys[numArrayKeys].scan_key = output_ikey;
+ so->arrayKeys[numArrayKeys].num_elems = num_elems;
+ so->arrayKeys[numArrayKeys].elem_values = elem_values;
+ numArrayKeys++;
+ output_ikey++; /* keep this scan key/array */
+ }
+
+ /* Set final number of equality-type array keys */
+ so->numArrayKeys = numArrayKeys;
+ /* Set number of scan keys remaining in arrayKeyData[] */
+ *new_numberOfKeys = output_ikey;
+
+ MemoryContextSwitchTo(oldContext);
+
+ return arrayKeyData;
+}
+
+/*
+ * _bt_preprocess_array_keys_final() -- fix up array scan key references
+ *
+ * When _bt_preprocess_array_keys performed initial array preprocessing, it
+ * set each array's array->scan_key to its scankey's arrayKeyData[] offset.
+ * This function handles translation of the scan key references from the
+ * BTArrayKeyInfo info array, from input scan key references (to the keys in
+ * arrayKeyData[]), into output references (to the keys in so->keyData[]).
+ * Caller's keyDataMap[] array tells us how to perform this remapping.
+ *
+ * Also finalizes so->orderProcs[] for the scan. Arrays already have an ORDER
+ * proc, which might need to be repositioned to its so->keyData[]-wise offset
+ * (very much like the remapping that we apply to array->scan_key references).
+ * Non-array equality strategy scan keys (that survived preprocessing) don't
+ * yet have an so->orderProcs[] entry, so we set one for them here.
+ *
+ * Also converts single-element array scan keys into equivalent non-array
+ * equality scan keys, which decrements so->numArrayKeys. It's possible that
+ * this will leave this new btrescan without any arrays at all. This isn't
+ * necessary for correctness; it's just an optimization. Non-array equality
+ * scan keys are slightly faster than equivalent array scan keys at runtime.
+ */
+static void
+_bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ Relation rel = scan->indexRelation;
+ int arrayidx = 0;
+ int last_equal_output_ikey PG_USED_FOR_ASSERTS_ONLY = -1;
+
+ Assert(so->qual_ok);
+
+ /*
+ * Nothing for us to do when _bt_preprocess_array_keys only had to deal
+ * with array inequalities
+ */
+ if (so->numArrayKeys == 0)
+ return;
+
+ for (int output_ikey = 0; output_ikey < so->numberOfKeys; output_ikey++)
+ {
+ ScanKey outkey = so->keyData + output_ikey;
+ int input_ikey;
+ bool found PG_USED_FOR_ASSERTS_ONLY = false;
+
+ Assert(outkey->sk_strategy != InvalidStrategy);
+
+ if (outkey->sk_strategy != BTEqualStrategyNumber)
+ continue;
+
+ input_ikey = keyDataMap[output_ikey];
+
+ Assert(last_equal_output_ikey < output_ikey);
+ Assert(last_equal_output_ikey < input_ikey);
+ last_equal_output_ikey = output_ikey;
+
+ /*
+ * We're lazy about looking up ORDER procs for non-array keys, since
+ * not all input keys become output keys. Take care of it now.
+ */
+ if (!(outkey->sk_flags & SK_SEARCHARRAY))
+ {
+ Oid elemtype;
+
+ /* No need for an ORDER proc given an IS NULL scan key */
+ if (outkey->sk_flags & SK_SEARCHNULL)
+ continue;
+
+ /*
+ * A non-required scan key doesn't need an ORDER proc, either
+ * (unless it's associated with an array, which this one isn't)
+ */
+ if (!(outkey->sk_flags & SK_BT_REQFWD))
+ continue;
+
+ elemtype = outkey->sk_subtype;
+ if (elemtype == InvalidOid)
+ elemtype = rel->rd_opcintype[outkey->sk_attno - 1];
+
+ _bt_setup_array_cmp(scan, outkey, elemtype,
+ &so->orderProcs[output_ikey], NULL);
+ continue;
+ }
+
+ /*
+ * Reorder existing array scan key so->orderProcs[] entries.
+ *
+ * Doing this in-place is safe because preprocessing is required to
+ * output all equality strategy scan keys in original input order
+ * (among each group of entries against the same index attribute).
+ * This is also the order that the arrays themselves appear in.
+ */
+ so->orderProcs[output_ikey] = so->orderProcs[input_ikey];
+
+ /* Fix-up array->scan_key references for arrays */
+ for (; arrayidx < so->numArrayKeys; arrayidx++)
+ {
+ BTArrayKeyInfo *array = &so->arrayKeys[arrayidx];
+
+ Assert(array->num_elems > 0);
+
+ if (array->scan_key == input_ikey)
+ {
+ /* found it */
+ array->scan_key = output_ikey;
+ found = true;
+
+ /*
+ * Transform array scan keys that have exactly 1 element
+ * remaining (following all prior preprocessing) into
+ * equivalent non-array scan keys.
+ */
+ if (array->num_elems == 1)
+ {
+ outkey->sk_flags &= ~SK_SEARCHARRAY;
+ outkey->sk_argument = array->elem_values[0];
+ so->numArrayKeys--;
+
+ /* If we're out of array keys, we can quit right away */
+ if (so->numArrayKeys == 0)
+ return;
+
+ /* Shift other arrays forward */
+ memmove(array, array + 1,
+ sizeof(BTArrayKeyInfo) *
+ (so->numArrayKeys - arrayidx));
+
+ /*
+ * Don't increment arrayidx (there was an entry that was
+ * just shifted forward to the offset at arrayidx, which
+ * will still need to be matched)
+ */
+ }
+ else
+ {
+ /* Match found, so done with this array */
+ arrayidx++;
+ }
+
+ break;
+ }
+ }
+
+ Assert(found);
+ }
+
+ /*
+ * Parallel index scans require space in shared memory to store the
+ * current array elements (for arrays kept by preprocessing) to schedule
+ * the next primitive index scan. The underlying structure is protected
+ * using a spinlock, so defensively limit its size. In practice this can
+ * only affect parallel scans that use an incomplete opfamily.
+ */
+ if (scan->parallel_scan && so->numArrayKeys > INDEX_MAX_KEYS)
+ ereport(ERROR,
+ (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+ errmsg_internal("number of array scan keys left by preprocessing (%d) exceeds the maximum allowed by parallel btree index scans (%d)",
+ so->numArrayKeys, INDEX_MAX_KEYS)));
+}
+
+/*
+ * _bt_find_extreme_element() -- get least or greatest array element
+ *
+ * scan and skey identify the index column, whose opfamily determines the
+ * comparison semantics. strat should be BTLessStrategyNumber to get the
+ * least element, or BTGreaterStrategyNumber to get the greatest.
+ */
+static Datum
+_bt_find_extreme_element(IndexScanDesc scan, ScanKey skey, Oid elemtype,
+ StrategyNumber strat,
+ Datum *elems, int nelems)
+{
+ Relation rel = scan->indexRelation;
+ Oid cmp_op;
+ RegProcedure cmp_proc;
+ FmgrInfo flinfo;
+ Datum result;
+ int i;
+
+ /*
+ * Look up the appropriate comparison operator in the opfamily.
+ *
+ * Note: it's possible that this would fail, if the opfamily is
+ * incomplete, but it seems quite unlikely that an opfamily would omit
+ * non-cross-type comparison operators for any datatype that it supports
+ * at all.
+ */
+ Assert(skey->sk_strategy != BTEqualStrategyNumber);
+ Assert(OidIsValid(elemtype));
+ cmp_op = get_opfamily_member(rel->rd_opfamily[skey->sk_attno - 1],
+ elemtype,
+ elemtype,
+ strat);
+ if (!OidIsValid(cmp_op))
+ elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
+ strat, elemtype, elemtype,
+ rel->rd_opfamily[skey->sk_attno - 1]);
+ cmp_proc = get_opcode(cmp_op);
+ if (!RegProcedureIsValid(cmp_proc))
+ elog(ERROR, "missing oprcode for operator %u", cmp_op);
+
+ fmgr_info(cmp_proc, &flinfo);
+
+ Assert(nelems > 0);
+ result = elems[0];
+ for (i = 1; i < nelems; i++)
+ {
+ if (DatumGetBool(FunctionCall2Coll(&flinfo,
+ skey->sk_collation,
+ elems[i],
+ result)))
+ result = elems[i];
+ }
+
+ return result;
+}
+
+/*
+ * _bt_setup_array_cmp() -- Set up array comparison functions
+ *
+ * Sets ORDER proc in caller's orderproc argument, which is used during binary
+ * searches of arrays during the index scan. Also sets a same-type ORDER proc
+ * in caller's *sortprocp argument, which is used when sorting the array.
+ *
+ * Preprocessing calls here with all equality strategy scan keys (when scan
+ * uses equality array keys), including those not associated with any array.
+ * See _bt_advance_array_keys for an explanation of why it'll need to treat
+ * simple scalar equality scan keys as degenerate single element arrays.
+ *
+ * Caller should pass an orderproc pointing to space that'll store the ORDER
+ * proc for the scan, and a *sortprocp pointing to its own separate space.
+ * When calling here for a non-array scan key, sortprocp arg should be NULL.
+ *
+ * In the common case where we don't need to deal with cross-type operators,
+ * only one ORDER proc is actually required by caller. We'll set *sortprocp
+ * to point to the same memory that caller's orderproc continues to point to.
+ * Otherwise, *sortprocp will continue to point to caller's own space. Either
+ * way, *sortprocp will point to a same-type ORDER proc (since that's the only
+ * safe way to sort/deduplicate the array associated with caller's scan key).
+ */
+static void
+_bt_setup_array_cmp(IndexScanDesc scan, ScanKey skey, Oid elemtype,
+ FmgrInfo *orderproc, FmgrInfo **sortprocp)
+{
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ Relation rel = scan->indexRelation;
+ RegProcedure cmp_proc;
+ Oid opcintype = rel->rd_opcintype[skey->sk_attno - 1];
+
+ Assert(skey->sk_strategy == BTEqualStrategyNumber);
+ Assert(OidIsValid(elemtype));
+
+ /*
+ * If scankey operator is not a cross-type comparison, we can use the
+ * cached comparison function; otherwise gotta look it up in the catalogs
+ */
+ if (elemtype == opcintype)
+ {
+ /* Set same-type ORDER procs for caller */
+ *orderproc = *index_getprocinfo(rel, skey->sk_attno, BTORDER_PROC);
+ if (sortprocp)
+ *sortprocp = orderproc;
+
+ return;
+ }
+
+ /*
+ * Look up the appropriate cross-type comparison function in the opfamily.
+ *
+ * Use the opclass input type as the left hand arg type, and the array
+ * element type as the right hand arg type (since binary searches use an
+ * index tuple's attribute value to search for a matching array element).
+ *
+ * Note: it's possible that this would fail, if the opfamily is
+ * incomplete, but only in cases where it's quite likely that _bt_first
+ * would fail in just the same way (had we not failed before it could).
+ */
+ cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
+ opcintype, elemtype, BTORDER_PROC);
+ if (!RegProcedureIsValid(cmp_proc))
+ elog(ERROR, "missing support function %d(%u,%u) for attribute %d of index \"%s\"",
+ BTORDER_PROC, opcintype, elemtype, skey->sk_attno,
+ RelationGetRelationName(rel));
+
+ /* Set cross-type ORDER proc for caller */
+ fmgr_info_cxt(cmp_proc, orderproc, so->arrayContext);
+
+ /* Done if caller doesn't actually have an array they'll need to sort */
+ if (!sortprocp)
+ return;
+
+ /*
+ * Look up the appropriate same-type comparison function in the opfamily.
+ *
+ * Note: it's possible that this would fail, if the opfamily is
+ * incomplete, but it seems quite unlikely that an opfamily would omit
+ * non-cross-type comparison procs for any datatype that it supports at
+ * all.
+ */
+ cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
+ elemtype, elemtype, BTORDER_PROC);
+ if (!RegProcedureIsValid(cmp_proc))
+ elog(ERROR, "missing support function %d(%u,%u) for attribute %d of index \"%s\"",
+ BTORDER_PROC, elemtype, elemtype,
+ skey->sk_attno, RelationGetRelationName(rel));
+
+ /* Set same-type ORDER proc for caller */
+ fmgr_info_cxt(cmp_proc, *sortprocp, so->arrayContext);
+}
+
+/*
+ * _bt_sort_array_elements() -- sort and de-dup array elements
+ *
+ * The array elements are sorted in-place, and the new number of elements
+ * after duplicate removal is returned.
+ *
+ * skey identifies the index column whose opfamily determines the comparison
+ * semantics, and sortproc is a corresponding ORDER proc. If reverse is true,
+ * we sort in descending order.
+ */
+static int
+_bt_sort_array_elements(ScanKey skey, FmgrInfo *sortproc, bool reverse,
+ Datum *elems, int nelems)
+{
+ BTSortArrayContext cxt;
+
+ if (nelems <= 1)
+ return nelems; /* no work to do */
+
+ /* Sort the array elements */
+ cxt.sortproc = sortproc;
+ cxt.collation = skey->sk_collation;
+ cxt.reverse = reverse;
+ qsort_arg(elems, nelems, sizeof(Datum),
+ _bt_compare_array_elements, &cxt);
+
+ /* Now scan the sorted elements and remove duplicates */
+ return qunique_arg(elems, nelems, sizeof(Datum),
+ _bt_compare_array_elements, &cxt);
+}
+
+/*
+ * _bt_merge_arrays() -- merge next array's elements into an original array
+ *
+ * Called when preprocessing encounters a pair of array equality scan keys,
+ * both against the same index attribute (during initial array preprocessing).
+ * Merging reorganizes caller's original array (the left hand arg) in-place,
+ * without ever copying elements from one array into the other. (Mixing the
+ * elements together like this would be wrong, since they don't necessarily
+ * use the same underlying element type, despite all the other similarities.)
+ *
+ * Both arrays must have already been sorted and deduplicated by calling
+ * _bt_sort_array_elements. sortproc is the same-type ORDER proc that was
+ * just used to sort and deduplicate caller's "next" array. We'll usually be
+ * able to reuse that order PROC to merge the arrays together now. If not,
+ * then we'll perform a separate ORDER proc lookup.
+ *
+ * If the opfamily doesn't supply a complete set of cross-type ORDER procs we
+ * may not be able to determine which elements are contradictory. If we have
+ * the required ORDER proc then we return true (and validly set *nelems_orig),
+ * guaranteeing that at least the next array can be considered redundant. We
+ * return false if the required comparisons cannot not be made (caller must
+ * keep both arrays when this happens).
+ */
+static bool
+_bt_merge_arrays(IndexScanDesc scan, ScanKey skey, FmgrInfo *sortproc,
+ bool reverse, Oid origelemtype, Oid nextelemtype,
+ Datum *elems_orig, int *nelems_orig,
+ Datum *elems_next, int nelems_next)
+{
+ Relation rel = scan->indexRelation;
+ BTScanOpaque so = (BTScanOpaque) scan->opaque;
+ BTSortArrayContext cxt;
+ int nelems_orig_start = *nelems_orig,
+ nelems_orig_merged = 0;
+ FmgrInfo *mergeproc = sortproc;
+ FmgrInfo crosstypeproc;
+
+ Assert(skey->sk_strategy == BTEqualStrategyNumber);
+ Assert(OidIsValid(origelemtype) && OidIsValid(nextelemtype));
+
+ if (origelemtype != nextelemtype)
+ {
+ RegProcedure cmp_proc;
+
+ /*
+ * Cross-array-element-type merging is required, so can't just reuse
+ * sortproc when merging
+ */
+ cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
+ origelemtype, nextelemtype, BTORDER_PROC);
+ if (!RegProcedureIsValid(cmp_proc))
+ {
+ /* Can't make the required comparisons */
+ return false;
+ }
+
+ /* We have all we need to determine redundancy/contradictoriness */
+ mergeproc = &crosstypeproc;
+ fmgr_info_cxt(cmp_proc, mergeproc, so->arrayContext);
+ }
+
+ cxt.sortproc = mergeproc;
+ cxt.collation = skey->sk_collation;
+ cxt.reverse = reverse;
+
+ for (int i = 0, j = 0; i < nelems_orig_start && j < nelems_next;)
+ {
+ Datum *oelem = elems_orig + i,
+ *nelem = elems_next + j;
+ int res = _bt_compare_array_elements(oelem, nelem, &cxt);
+
+ if (res == 0)
+ {
+ elems_orig[nelems_orig_merged++] = *oelem;
+ i++;
+ j++;
+ }
+ else if (res < 0)
+ i++;
+ else /* res > 0 */
+ j++;
+ }
+
+ *nelems_orig = nelems_orig_merged;
+
+ return true;
+}
+
+/*
+ * qsort_arg comparator for sorting array elements
+ */
+static int
+_bt_compare_array_elements(const void *a, const void *b, void *arg)
+{
+ Datum da = *((const Datum *) a);
+ Datum db = *((const Datum *) b);
+ BTSortArrayContext *cxt = (BTSortArrayContext *) arg;
+ int32 compare;
+
+ compare = DatumGetInt32(FunctionCall2Coll(cxt->sortproc,
+ cxt->collation,
+ da, db));
+ if (cxt->reverse)
+ INVERT_COMPARE_RESULT(compare);
+ return compare;
+}
#include "access/nbtree.h"
#include "access/reloptions.h"
-#include "access/relscan.h"
#include "commands/progress.h"
-#include "lib/qunique.h"
#include "miscadmin.h"
-#include "utils/array.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
-#include "utils/memutils.h"
-#include "utils/rel.h"
#define LOOK_AHEAD_REQUIRED_RECHECKS 3
#define LOOK_AHEAD_DEFAULT_DISTANCE 5
-typedef struct BTSortArrayContext
-{
- FmgrInfo *sortproc;
- Oid collation;
- bool reverse;
-} BTSortArrayContext;
-
-typedef struct BTScanKeyPreproc
-{
- ScanKey inkey;
- int inkeyi;
- int arrayidx;
-} BTScanKeyPreproc;
-
-static void _bt_setup_array_cmp(IndexScanDesc scan, ScanKey skey, Oid elemtype,
- FmgrInfo *orderproc, FmgrInfo **sortprocp);
-static Datum _bt_find_extreme_element(IndexScanDesc scan, ScanKey skey,
- Oid elemtype, StrategyNumber strat,
- Datum *elems, int nelems);
-static int _bt_sort_array_elements(ScanKey skey, FmgrInfo *sortproc,
- bool reverse, Datum *elems, int nelems);
-static bool _bt_merge_arrays(IndexScanDesc scan, ScanKey skey,
- FmgrInfo *sortproc, bool reverse,
- Oid origelemtype, Oid nextelemtype,
- Datum *elems_orig, int *nelems_orig,
- Datum *elems_next, int nelems_next);
-static bool _bt_compare_array_scankey_args(IndexScanDesc scan,
- ScanKey arraysk, ScanKey skey,
- FmgrInfo *orderproc, BTArrayKeyInfo *array,
- bool *qual_ok);
-static ScanKey _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys);
-static void _bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap);
-static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
static inline int32 _bt_compare_array_skey(FmgrInfo *orderproc,
Datum tupdatum, bool tupnull,
Datum arrdatum, ScanKey cur);
-static int _bt_binsrch_array_skey(FmgrInfo *orderproc,
- bool cur_elem_trig, ScanDirection dir,
- Datum tupdatum, bool tupnull,
- BTArrayKeyInfo *array, ScanKey cur,
- int32 *set_elem_result);
static bool _bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir);
static void _bt_rewind_nonrequired_arrays(IndexScanDesc scan, ScanDirection dir);
static bool _bt_tuple_before_array_skeys(IndexScanDesc scan, ScanDirection dir,
static bool _bt_verify_arrays_bt_first(IndexScanDesc scan, ScanDirection dir);
static bool _bt_verify_keys_with_arraykeys(IndexScanDesc scan);
#endif
-static bool _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
- ScanKey leftarg, ScanKey rightarg,
- BTArrayKeyInfo *array, FmgrInfo *orderproc,
- bool *result);
-static bool _bt_fix_scankey_strategy(ScanKey skey, int16 *indoption);
-static void _bt_mark_scankey_required(ScanKey skey);
static bool _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
IndexTuple tuple, int tupnatts, TupleDesc tupdesc,
bool advancenonrequired, bool prechecked, bool firstmatch,
}
}
-
/*
- * _bt_preprocess_array_keys() -- Preprocess SK_SEARCHARRAY scan keys
- *
- * If there are any SK_SEARCHARRAY scan keys, deconstruct the array(s) and
- * set up BTArrayKeyInfo info for each one that is an equality-type key.
- * Returns modified scan keys as input for further, standard preprocessing.
- *
- * Currently we perform two kinds of preprocessing to deal with redundancies.
- * For inequality array keys, it's sufficient to find the extreme element
- * value and replace the whole array with that scalar value. This eliminates
- * all but one array element as redundant. Similarly, we are capable of
- * "merging together" multiple equality array keys (from two or more input
- * scan keys) into a single output scan key containing only the intersecting
- * array elements. This can eliminate many redundant array elements, as well
- * as eliminating whole array scan keys as redundant. It can also allow us to
- * detect contradictory quals.
+ * _bt_compare_array_skey() -- apply array comparison function
*
- * Caller must pass *new_numberOfKeys to give us a way to change the number of
- * scan keys that caller treats as input to standard preprocessing steps. The
- * returned array is smaller than scan->keyData[] when we could eliminate a
- * redundant array scan key (redundant with another array scan key). It is
- * convenient for _bt_preprocess_keys caller to have to deal with no more than
- * one equality strategy array scan key per index attribute. We'll always be
- * able to set things up that way when complete opfamilies are used.
+ * Compares caller's tuple attribute value to a scan key/array element.
+ * Helper function used during binary searches of SK_SEARCHARRAY arrays.
*
- * We set the scan key references from the scan's BTArrayKeyInfo info array to
- * offsets into the temp modified input array returned to caller. Scans that
- * have array keys should call _bt_preprocess_array_keys_final when standard
- * preprocessing steps are complete. This will convert the scan key offset
- * references into references to the scan's so->keyData[] output scan keys.
+ * This routine returns:
+ * <0 if tupdatum < arrdatum;
+ * 0 if tupdatum == arrdatum;
+ * >0 if tupdatum > arrdatum.
*
- * Note: the reason we need to return a temp scan key array, rather than just
- * scribbling on scan->keyData, is that callers are permitted to call btrescan
- * without supplying a new set of scankey data.
- */
-static ScanKey
-_bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
+ * This is essentially the same interface as _bt_compare: both functions
+ * compare the value that they're searching for to a binary search pivot.
+ * However, unlike _bt_compare, this function's "tuple argument" comes first,
+ * while its "array/scankey argument" comes second.
+*/
+static inline int32
+_bt_compare_array_skey(FmgrInfo *orderproc,
+ Datum tupdatum, bool tupnull,
+ Datum arrdatum, ScanKey cur)
{
- BTScanOpaque so = (BTScanOpaque) scan->opaque;
- Relation rel = scan->indexRelation;
- int numberOfKeys = scan->numberOfKeys;
- int16 *indoption = rel->rd_indoption;
- int numArrayKeys,
- output_ikey = 0;
- int origarrayatt = InvalidAttrNumber,
- origarraykey = -1;
- Oid origelemtype = InvalidOid;
- ScanKey cur;
- MemoryContext oldContext;
- ScanKey arrayKeyData; /* modified copy of scan->keyData */
-
- Assert(numberOfKeys);
-
- /* Quick check to see if there are any array keys */
- numArrayKeys = 0;
- for (int i = 0; i < numberOfKeys; i++)
- {
- cur = &scan->keyData[i];
- if (cur->sk_flags & SK_SEARCHARRAY)
- {
- numArrayKeys++;
- Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
- /* If any arrays are null as a whole, we can quit right now. */
- if (cur->sk_flags & SK_ISNULL)
- {
- so->qual_ok = false;
- return NULL;
- }
- }
- }
+ int32 result = 0;
- /* Quit if nothing to do. */
- if (numArrayKeys == 0)
- return NULL;
+ Assert(cur->sk_strategy == BTEqualStrategyNumber);
- /*
- * Make a scan-lifespan context to hold array-associated data, or reset it
- * if we already have one from a previous rescan cycle.
- */
- if (so->arrayContext == NULL)
- so->arrayContext = AllocSetContextCreate(CurrentMemoryContext,
- "BTree array context",
- ALLOCSET_SMALL_SIZES);
+ if (tupnull) /* NULL tupdatum */
+ {
+ if (cur->sk_flags & SK_ISNULL)
+ result = 0; /* NULL "=" NULL */
+ else if (cur->sk_flags & SK_BT_NULLS_FIRST)
+ result = -1; /* NULL "<" NOT_NULL */
+ else
+ result = 1; /* NULL ">" NOT_NULL */
+ }
+ else if (cur->sk_flags & SK_ISNULL) /* NOT_NULL tupdatum, NULL arrdatum */
+ {
+ if (cur->sk_flags & SK_BT_NULLS_FIRST)
+ result = 1; /* NOT_NULL ">" NULL */
+ else
+ result = -1; /* NOT_NULL "<" NULL */
+ }
else
- MemoryContextReset(so->arrayContext);
-
- oldContext = MemoryContextSwitchTo(so->arrayContext);
-
- /* Create output scan keys in the workspace context */
- arrayKeyData = (ScanKey) palloc(numberOfKeys * sizeof(ScanKeyData));
-
- /* Allocate space for per-array data in the workspace context */
- so->arrayKeys = (BTArrayKeyInfo *) palloc(numArrayKeys * sizeof(BTArrayKeyInfo));
-
- /* Allocate space for ORDER procs used to help _bt_checkkeys */
- so->orderProcs = (FmgrInfo *) palloc(numberOfKeys * sizeof(FmgrInfo));
-
- /* Now process each array key */
- numArrayKeys = 0;
- for (int input_ikey = 0; input_ikey < numberOfKeys; input_ikey++)
{
- FmgrInfo sortproc;
- FmgrInfo *sortprocp = &sortproc;
- Oid elemtype;
- bool reverse;
- ArrayType *arrayval;
- int16 elmlen;
- bool elmbyval;
- char elmalign;
- int num_elems;
- Datum *elem_values;
- bool *elem_nulls;
- int num_nonnulls;
- int j;
-
/*
- * Provisionally copy scan key into arrayKeyData[] array we'll return
- * to _bt_preprocess_keys caller
+ * Like _bt_compare, we need to be careful of cross-type comparisons,
+ * so the left value has to be the value that came from an index tuple
*/
- cur = &arrayKeyData[output_ikey];
- *cur = scan->keyData[input_ikey];
-
- if (!(cur->sk_flags & SK_SEARCHARRAY))
- {
- output_ikey++; /* keep this non-array scan key */
- continue;
- }
+ result = DatumGetInt32(FunctionCall2Coll(orderproc, cur->sk_collation,
+ tupdatum, arrdatum));
/*
- * Deconstruct the array into elements
+ * We flip the sign by following the obvious rule: flip whenever the
+ * column is a DESC column.
+ *
+ * _bt_compare does it the wrong way around (flip when *ASC*) in order
+ * to compensate for passing its orderproc arguments backwards. We
+ * don't need to play these games because we find it natural to pass
+ * tupdatum as the left value (and arrdatum as the right value).
*/
- arrayval = DatumGetArrayTypeP(cur->sk_argument);
- /* We could cache this data, but not clear it's worth it */
- get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
- &elmlen, &elmbyval, &elmalign);
- deconstruct_array(arrayval,
- ARR_ELEMTYPE(arrayval),
- elmlen, elmbyval, elmalign,
- &elem_values, &elem_nulls, &num_elems);
+ if (cur->sk_flags & SK_BT_DESC)
+ INVERT_COMPARE_RESULT(result);
+ }
- /*
- * Compress out any null elements. We can ignore them since we assume
- * all btree operators are strict.
- */
- num_nonnulls = 0;
- for (j = 0; j < num_elems; j++)
- {
- if (!elem_nulls[j])
- elem_values[num_nonnulls++] = elem_values[j];
- }
+ return result;
+}
- /* We could pfree(elem_nulls) now, but not worth the cycles */
+/*
+ * _bt_binsrch_array_skey() -- Binary search for next matching array key
+ *
+ * Returns an index to the first array element >= caller's tupdatum argument.
+ * This convention is more natural for forwards scan callers, but that can't
+ * really matter to backwards scan callers. Both callers require handling for
+ * the case where the match we return is < tupdatum, and symmetric handling
+ * for the case where our best match is > tupdatum.
+ *
+ * Also sets *set_elem_result to the result _bt_compare_array_skey returned
+ * when we used it to compare the matching array element to tupdatum/tupnull.
+ *
+ * cur_elem_trig indicates if array advancement was triggered by this array's
+ * scan key, and that the array is for a required scan key. We can apply this
+ * information to find the next matching array element in the current scan
+ * direction using far fewer comparisons (fewer on average, compared to naive
+ * binary search). This scheme takes advantage of an important property of
+ * required arrays: required arrays always advance in lockstep with the index
+ * scan's progress through the index's key space.
+ */
+int
+_bt_binsrch_array_skey(FmgrInfo *orderproc,
+ bool cur_elem_trig, ScanDirection dir,
+ Datum tupdatum, bool tupnull,
+ BTArrayKeyInfo *array, ScanKey cur,
+ int32 *set_elem_result)
+{
+ int low_elem = 0,
+ mid_elem = -1,
+ high_elem = array->num_elems - 1,
+ result = 0;
+ Datum arrdatum;
- /* If there's no non-nulls, the scan qual is unsatisfiable */
- if (num_nonnulls == 0)
- {
- so->qual_ok = false;
- break;
- }
+ Assert(cur->sk_flags & SK_SEARCHARRAY);
+ Assert(cur->sk_strategy == BTEqualStrategyNumber);
- /*
- * Determine the nominal datatype of the array elements. We have to
- * support the convention that sk_subtype == InvalidOid means the
- * opclass input type; this is a hack to simplify life for
- * ScanKeyInit().
- */
- elemtype = cur->sk_subtype;
- if (elemtype == InvalidOid)
- elemtype = rel->rd_opcintype[cur->sk_attno - 1];
+ if (cur_elem_trig)
+ {
+ Assert(!ScanDirectionIsNoMovement(dir));
+ Assert(cur->sk_flags & SK_BT_REQFWD);
/*
- * If the comparison operator is not equality, then the array qual
- * degenerates to a simple comparison against the smallest or largest
- * non-null array element, as appropriate.
+ * When the scan key that triggered array advancement is a required
+ * array scan key, it is now certain that the current array element
+ * (plus all prior elements relative to the current scan direction)
+ * cannot possibly be at or ahead of the corresponding tuple value.
+ * (_bt_checkkeys must have called _bt_tuple_before_array_skeys, which
+ * makes sure this is true as a condition of advancing the arrays.)
+ *
+ * This makes it safe to exclude array elements up to and including
+ * the former-current array element from our search.
+ *
+ * Separately, when array advancement was triggered by a required scan
+ * key, the array element immediately after the former-current element
+ * is often either an exact tupdatum match, or a "close by" near-match
+ * (a near-match tupdatum is one whose key space falls _between_ the
+ * former-current and new-current array elements). We'll detect both
+ * cases via an optimistic comparison of the new search lower bound
+ * (or new search upper bound in the case of backwards scans).
*/
- switch (cur->sk_strategy)
+ if (ScanDirectionIsForward(dir))
{
- case BTLessStrategyNumber:
- case BTLessEqualStrategyNumber:
- cur->sk_argument =
- _bt_find_extreme_element(scan, cur, elemtype,
- BTGreaterStrategyNumber,
- elem_values, num_nonnulls);
- output_ikey++; /* keep this transformed scan key */
- continue;
- case BTEqualStrategyNumber:
- /* proceed with rest of loop */
- break;
- case BTGreaterEqualStrategyNumber:
- case BTGreaterStrategyNumber:
- cur->sk_argument =
- _bt_find_extreme_element(scan, cur, elemtype,
- BTLessStrategyNumber,
- elem_values, num_nonnulls);
- output_ikey++; /* keep this transformed scan key */
- continue;
- default:
- elog(ERROR, "unrecognized StrategyNumber: %d",
- (int) cur->sk_strategy);
- break;
- }
+ low_elem = array->cur_elem + 1; /* old cur_elem exhausted */
- /*
- * We'll need a 3-way ORDER proc to perform binary searches for the
- * next matching array element. Set that up now.
- *
- * Array scan keys with cross-type equality operators will require a
- * separate same-type ORDER proc for sorting their array. Otherwise,
- * sortproc just points to the same proc used during binary searches.
- */
- _bt_setup_array_cmp(scan, cur, elemtype,
- &so->orderProcs[output_ikey], &sortprocp);
+ /* Compare prospective new cur_elem (also the new lower bound) */
+ if (high_elem >= low_elem)
+ {
+ arrdatum = array->elem_values[low_elem];
+ result = _bt_compare_array_skey(orderproc, tupdatum, tupnull,
+ arrdatum, cur);
- /*
- * Sort the non-null elements and eliminate any duplicates. We must
- * sort in the same ordering used by the index column, so that the
- * arrays can be advanced in lockstep with the scan's progress through
- * the index's key space.
- */
- reverse = (indoption[cur->sk_attno - 1] & INDOPTION_DESC) != 0;
- num_elems = _bt_sort_array_elements(cur, sortprocp, reverse,
- elem_values, num_nonnulls);
+ if (result <= 0)
+ {
+ /* Optimistic comparison optimization worked out */
+ *set_elem_result = result;
+ return low_elem;
+ }
+ mid_elem = low_elem;
+ low_elem++; /* this cur_elem exhausted, too */
+ }
- if (origarrayatt == cur->sk_attno)
+ if (high_elem < low_elem)
+ {
+ /* Caller needs to perform "beyond end" array advancement */
+ *set_elem_result = 1;
+ return high_elem;
+ }
+ }
+ else
{
- BTArrayKeyInfo *orig = &so->arrayKeys[origarraykey];
+ high_elem = array->cur_elem - 1; /* old cur_elem exhausted */
- /*
- * This array scan key is redundant with a previous equality
- * operator array scan key. Merge the two arrays together to
- * eliminate contradictory non-intersecting elements (or try to).
- *
- * We merge this next array back into attribute's original array.
- */
- Assert(arrayKeyData[orig->scan_key].sk_attno == cur->sk_attno);
- Assert(arrayKeyData[orig->scan_key].sk_collation ==
- cur->sk_collation);
- if (_bt_merge_arrays(scan, cur, sortprocp, reverse,
- origelemtype, elemtype,
- orig->elem_values, &orig->num_elems,
- elem_values, num_elems))
+ /* Compare prospective new cur_elem (also the new upper bound) */
+ if (high_elem >= low_elem)
{
- /* Successfully eliminated this array */
- pfree(elem_values);
+ arrdatum = array->elem_values[high_elem];
+ result = _bt_compare_array_skey(orderproc, tupdatum, tupnull,
+ arrdatum, cur);
- /*
- * If no intersecting elements remain in the original array,
- * the scan qual is unsatisfiable
- */
- if (orig->num_elems == 0)
+ if (result >= 0)
{
- so->qual_ok = false;
- break;
+ /* Optimistic comparison optimization worked out */
+ *set_elem_result = result;
+ return high_elem;
}
-
- /* Throw away this scan key/array */
- continue;
+ mid_elem = high_elem;
+ high_elem--; /* this cur_elem exhausted, too */
}
- /*
- * Unable to merge this array with previous array due to a lack of
- * suitable cross-type opfamily support. Will need to keep both
- * scan keys/arrays.
- */
+ if (high_elem < low_elem)
+ {
+ /* Caller needs to perform "beyond end" array advancement */
+ *set_elem_result = -1;
+ return low_elem;
+ }
}
- else
+ }
+
+ while (high_elem > low_elem)
+ {
+ mid_elem = low_elem + ((high_elem - low_elem) / 2);
+ arrdatum = array->elem_values[mid_elem];
+
+ result = _bt_compare_array_skey(orderproc, tupdatum, tupnull,
+ arrdatum, cur);
+
+ if (result == 0)
{
/*
- * This array is the first for current index attribute.
- *
- * If it turns out to not be the last array (that is, if the next
- * array is redundantly applied to this same index attribute),
- * we'll then treat this array as the attribute's "original" array
- * when merging.
+ * It's safe to quit as soon as we see an equal array element.
+ * This often saves an extra comparison or two...
*/
- origarrayatt = cur->sk_attno;
- origarraykey = numArrayKeys;
- origelemtype = elemtype;
+ low_elem = mid_elem;
+ break;
}
- /*
- * And set up the BTArrayKeyInfo data.
- *
- * Note: _bt_preprocess_array_keys_final will fix-up each array's
- * scan_key field later on, after so->keyData[] has been finalized.
- */
- so->arrayKeys[numArrayKeys].scan_key = output_ikey;
- so->arrayKeys[numArrayKeys].num_elems = num_elems;
- so->arrayKeys[numArrayKeys].elem_values = elem_values;
- numArrayKeys++;
- output_ikey++; /* keep this scan key/array */
+ if (result > 0)
+ low_elem = mid_elem + 1;
+ else
+ high_elem = mid_elem;
}
- /* Set final number of equality-type array keys */
- so->numArrayKeys = numArrayKeys;
- /* Set number of scan keys remaining in arrayKeyData[] */
- *new_numberOfKeys = output_ikey;
+ /*
+ * ...but our caller also cares about how its searched-for tuple datum
+ * compares to the low_elem datum. Must always set *set_elem_result with
+ * the result of that comparison specifically.
+ */
+ if (low_elem != mid_elem)
+ result = _bt_compare_array_skey(orderproc, tupdatum, tupnull,
+ array->elem_values[low_elem], cur);
- MemoryContextSwitchTo(oldContext);
+ *set_elem_result = result;
- return arrayKeyData;
+ return low_elem;
}
/*
- * _bt_preprocess_array_keys_final() -- fix up array scan key references
- *
- * When _bt_preprocess_array_keys performed initial array preprocessing, it
- * set each array's array->scan_key to its scankey's arrayKeyData[] offset.
- * This function handles translation of the scan key references from the
- * BTArrayKeyInfo info array, from input scan key references (to the keys in
- * arrayKeyData[]), into output references (to the keys in so->keyData[]).
- * Caller's keyDataMap[] array tells us how to perform this remapping.
- *
- * Also finalizes so->orderProcs[] for the scan. Arrays already have an ORDER
- * proc, which might need to be repositioned to its so->keyData[]-wise offset
- * (very much like the remapping that we apply to array->scan_key references).
- * Non-array equality strategy scan keys (that survived preprocessing) don't
- * yet have an so->orderProcs[] entry, so we set one for them here.
+ * _bt_start_array_keys() -- Initialize array keys at start of a scan
*
- * Also converts single-element array scan keys into equivalent non-array
- * equality scan keys, which decrements so->numArrayKeys. It's possible that
- * this will leave this new btrescan without any arrays at all. This isn't
- * necessary for correctness; it's just an optimization. Non-array equality
- * scan keys are slightly faster than equivalent array scan keys at runtime.
+ * Set up the cur_elem counters and fill in the first sk_argument value for
+ * each array scankey.
*/
-static void
-_bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap)
+void
+_bt_start_array_keys(IndexScanDesc scan, ScanDirection dir)
{
BTScanOpaque so = (BTScanOpaque) scan->opaque;
- Relation rel = scan->indexRelation;
- int arrayidx = 0;
- int last_equal_output_ikey PG_USED_FOR_ASSERTS_ONLY = -1;
+ int i;
+ Assert(so->numArrayKeys);
Assert(so->qual_ok);
- /*
- * Nothing for us to do when _bt_preprocess_array_keys only had to deal
- * with array inequalities
- */
- if (so->numArrayKeys == 0)
- return;
-
- for (int output_ikey = 0; output_ikey < so->numberOfKeys; output_ikey++)
+ for (i = 0; i < so->numArrayKeys; i++)
{
- ScanKey outkey = so->keyData + output_ikey;
- int input_ikey;
- bool found PG_USED_FOR_ASSERTS_ONLY = false;
-
- Assert(outkey->sk_strategy != InvalidStrategy);
-
- if (outkey->sk_strategy != BTEqualStrategyNumber)
- continue;
-
- input_ikey = keyDataMap[output_ikey];
-
- Assert(last_equal_output_ikey < output_ikey);
- Assert(last_equal_output_ikey < input_ikey);
- last_equal_output_ikey = output_ikey;
-
- /*
- * We're lazy about looking up ORDER procs for non-array keys, since
- * not all input keys become output keys. Take care of it now.
- */
- if (!(outkey->sk_flags & SK_SEARCHARRAY))
- {
- Oid elemtype;
-
- /* No need for an ORDER proc given an IS NULL scan key */
- if (outkey->sk_flags & SK_SEARCHNULL)
- continue;
-
- /*
- * A non-required scan key doesn't need an ORDER proc, either
- * (unless it's associated with an array, which this one isn't)
- */
- if (!(outkey->sk_flags & SK_BT_REQFWD))
- continue;
-
- elemtype = outkey->sk_subtype;
- if (elemtype == InvalidOid)
- elemtype = rel->rd_opcintype[outkey->sk_attno - 1];
-
- _bt_setup_array_cmp(scan, outkey, elemtype,
- &so->orderProcs[output_ikey], NULL);
- continue;
- }
-
- /*
- * Reorder existing array scan key so->orderProcs[] entries.
- *
- * Doing this in-place is safe because preprocessing is required to
- * output all equality strategy scan keys in original input order
- * (among each group of entries against the same index attribute).
- * This is also the order that the arrays themselves appear in.
- */
- so->orderProcs[output_ikey] = so->orderProcs[input_ikey];
-
- /* Fix-up array->scan_key references for arrays */
- for (; arrayidx < so->numArrayKeys; arrayidx++)
- {
- BTArrayKeyInfo *array = &so->arrayKeys[arrayidx];
-
- Assert(array->num_elems > 0);
-
- if (array->scan_key == input_ikey)
- {
- /* found it */
- array->scan_key = output_ikey;
- found = true;
-
- /*
- * Transform array scan keys that have exactly 1 element
- * remaining (following all prior preprocessing) into
- * equivalent non-array scan keys.
- */
- if (array->num_elems == 1)
- {
- outkey->sk_flags &= ~SK_SEARCHARRAY;
- outkey->sk_argument = array->elem_values[0];
- so->numArrayKeys--;
-
- /* If we're out of array keys, we can quit right away */
- if (so->numArrayKeys == 0)
- return;
-
- /* Shift other arrays forward */
- memmove(array, array + 1,
- sizeof(BTArrayKeyInfo) *
- (so->numArrayKeys - arrayidx));
-
- /*
- * Don't increment arrayidx (there was an entry that was
- * just shifted forward to the offset at arrayidx, which
- * will still need to be matched)
- */
- }
- else
- {
- /* Match found, so done with this array */
- arrayidx++;
- }
-
- break;
- }
- }
-
- Assert(found);
- }
-
- /*
- * Parallel index scans require space in shared memory to store the
- * current array elements (for arrays kept by preprocessing) to schedule
- * the next primitive index scan. The underlying structure is protected
- * using a spinlock, so defensively limit its size. In practice this can
- * only affect parallel scans that use an incomplete opfamily.
- */
- if (scan->parallel_scan && so->numArrayKeys > INDEX_MAX_KEYS)
- ereport(ERROR,
- (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
- errmsg_internal("number of array scan keys left by preprocessing (%d) exceeds the maximum allowed by parallel btree index scans (%d)",
- so->numArrayKeys, INDEX_MAX_KEYS)));
-}
-
-/*
- * _bt_setup_array_cmp() -- Set up array comparison functions
- *
- * Sets ORDER proc in caller's orderproc argument, which is used during binary
- * searches of arrays during the index scan. Also sets a same-type ORDER proc
- * in caller's *sortprocp argument, which is used when sorting the array.
- *
- * Preprocessing calls here with all equality strategy scan keys (when scan
- * uses equality array keys), including those not associated with any array.
- * See _bt_advance_array_keys for an explanation of why it'll need to treat
- * simple scalar equality scan keys as degenerate single element arrays.
- *
- * Caller should pass an orderproc pointing to space that'll store the ORDER
- * proc for the scan, and a *sortprocp pointing to its own separate space.
- * When calling here for a non-array scan key, sortprocp arg should be NULL.
- *
- * In the common case where we don't need to deal with cross-type operators,
- * only one ORDER proc is actually required by caller. We'll set *sortprocp
- * to point to the same memory that caller's orderproc continues to point to.
- * Otherwise, *sortprocp will continue to point to caller's own space. Either
- * way, *sortprocp will point to a same-type ORDER proc (since that's the only
- * safe way to sort/deduplicate the array associated with caller's scan key).
- */
-static void
-_bt_setup_array_cmp(IndexScanDesc scan, ScanKey skey, Oid elemtype,
- FmgrInfo *orderproc, FmgrInfo **sortprocp)
-{
- BTScanOpaque so = (BTScanOpaque) scan->opaque;
- Relation rel = scan->indexRelation;
- RegProcedure cmp_proc;
- Oid opcintype = rel->rd_opcintype[skey->sk_attno - 1];
-
- Assert(skey->sk_strategy == BTEqualStrategyNumber);
- Assert(OidIsValid(elemtype));
-
- /*
- * If scankey operator is not a cross-type comparison, we can use the
- * cached comparison function; otherwise gotta look it up in the catalogs
- */
- if (elemtype == opcintype)
- {
- /* Set same-type ORDER procs for caller */
- *orderproc = *index_getprocinfo(rel, skey->sk_attno, BTORDER_PROC);
- if (sortprocp)
- *sortprocp = orderproc;
-
- return;
- }
-
- /*
- * Look up the appropriate cross-type comparison function in the opfamily.
- *
- * Use the opclass input type as the left hand arg type, and the array
- * element type as the right hand arg type (since binary searches use an
- * index tuple's attribute value to search for a matching array element).
- *
- * Note: it's possible that this would fail, if the opfamily is
- * incomplete, but only in cases where it's quite likely that _bt_first
- * would fail in just the same way (had we not failed before it could).
- */
- cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
- opcintype, elemtype, BTORDER_PROC);
- if (!RegProcedureIsValid(cmp_proc))
- elog(ERROR, "missing support function %d(%u,%u) for attribute %d of index \"%s\"",
- BTORDER_PROC, opcintype, elemtype, skey->sk_attno,
- RelationGetRelationName(rel));
-
- /* Set cross-type ORDER proc for caller */
- fmgr_info_cxt(cmp_proc, orderproc, so->arrayContext);
-
- /* Done if caller doesn't actually have an array they'll need to sort */
- if (!sortprocp)
- return;
-
- /*
- * Look up the appropriate same-type comparison function in the opfamily.
- *
- * Note: it's possible that this would fail, if the opfamily is
- * incomplete, but it seems quite unlikely that an opfamily would omit
- * non-cross-type comparison procs for any datatype that it supports at
- * all.
- */
- cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
- elemtype, elemtype, BTORDER_PROC);
- if (!RegProcedureIsValid(cmp_proc))
- elog(ERROR, "missing support function %d(%u,%u) for attribute %d of index \"%s\"",
- BTORDER_PROC, elemtype, elemtype,
- skey->sk_attno, RelationGetRelationName(rel));
-
- /* Set same-type ORDER proc for caller */
- fmgr_info_cxt(cmp_proc, *sortprocp, so->arrayContext);
-}
-
-/*
- * _bt_find_extreme_element() -- get least or greatest array element
- *
- * scan and skey identify the index column, whose opfamily determines the
- * comparison semantics. strat should be BTLessStrategyNumber to get the
- * least element, or BTGreaterStrategyNumber to get the greatest.
- */
-static Datum
-_bt_find_extreme_element(IndexScanDesc scan, ScanKey skey, Oid elemtype,
- StrategyNumber strat,
- Datum *elems, int nelems)
-{
- Relation rel = scan->indexRelation;
- Oid cmp_op;
- RegProcedure cmp_proc;
- FmgrInfo flinfo;
- Datum result;
- int i;
-
- /*
- * Look up the appropriate comparison operator in the opfamily.
- *
- * Note: it's possible that this would fail, if the opfamily is
- * incomplete, but it seems quite unlikely that an opfamily would omit
- * non-cross-type comparison operators for any datatype that it supports
- * at all.
- */
- Assert(skey->sk_strategy != BTEqualStrategyNumber);
- Assert(OidIsValid(elemtype));
- cmp_op = get_opfamily_member(rel->rd_opfamily[skey->sk_attno - 1],
- elemtype,
- elemtype,
- strat);
- if (!OidIsValid(cmp_op))
- elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
- strat, elemtype, elemtype,
- rel->rd_opfamily[skey->sk_attno - 1]);
- cmp_proc = get_opcode(cmp_op);
- if (!RegProcedureIsValid(cmp_proc))
- elog(ERROR, "missing oprcode for operator %u", cmp_op);
-
- fmgr_info(cmp_proc, &flinfo);
-
- Assert(nelems > 0);
- result = elems[0];
- for (i = 1; i < nelems; i++)
- {
- if (DatumGetBool(FunctionCall2Coll(&flinfo,
- skey->sk_collation,
- elems[i],
- result)))
- result = elems[i];
- }
-
- return result;
-}
-
-/*
- * _bt_sort_array_elements() -- sort and de-dup array elements
- *
- * The array elements are sorted in-place, and the new number of elements
- * after duplicate removal is returned.
- *
- * skey identifies the index column whose opfamily determines the comparison
- * semantics, and sortproc is a corresponding ORDER proc. If reverse is true,
- * we sort in descending order.
- */
-static int
-_bt_sort_array_elements(ScanKey skey, FmgrInfo *sortproc, bool reverse,
- Datum *elems, int nelems)
-{
- BTSortArrayContext cxt;
-
- if (nelems <= 1)
- return nelems; /* no work to do */
-
- /* Sort the array elements */
- cxt.sortproc = sortproc;
- cxt.collation = skey->sk_collation;
- cxt.reverse = reverse;
- qsort_arg(elems, nelems, sizeof(Datum),
- _bt_compare_array_elements, &cxt);
-
- /* Now scan the sorted elements and remove duplicates */
- return qunique_arg(elems, nelems, sizeof(Datum),
- _bt_compare_array_elements, &cxt);
-}
-
-/*
- * _bt_merge_arrays() -- merge next array's elements into an original array
- *
- * Called when preprocessing encounters a pair of array equality scan keys,
- * both against the same index attribute (during initial array preprocessing).
- * Merging reorganizes caller's original array (the left hand arg) in-place,
- * without ever copying elements from one array into the other. (Mixing the
- * elements together like this would be wrong, since they don't necessarily
- * use the same underlying element type, despite all the other similarities.)
- *
- * Both arrays must have already been sorted and deduplicated by calling
- * _bt_sort_array_elements. sortproc is the same-type ORDER proc that was
- * just used to sort and deduplicate caller's "next" array. We'll usually be
- * able to reuse that order PROC to merge the arrays together now. If not,
- * then we'll perform a separate ORDER proc lookup.
- *
- * If the opfamily doesn't supply a complete set of cross-type ORDER procs we
- * may not be able to determine which elements are contradictory. If we have
- * the required ORDER proc then we return true (and validly set *nelems_orig),
- * guaranteeing that at least the next array can be considered redundant. We
- * return false if the required comparisons cannot not be made (caller must
- * keep both arrays when this happens).
- */
-static bool
-_bt_merge_arrays(IndexScanDesc scan, ScanKey skey, FmgrInfo *sortproc,
- bool reverse, Oid origelemtype, Oid nextelemtype,
- Datum *elems_orig, int *nelems_orig,
- Datum *elems_next, int nelems_next)
-{
- Relation rel = scan->indexRelation;
- BTScanOpaque so = (BTScanOpaque) scan->opaque;
- BTSortArrayContext cxt;
- int nelems_orig_start = *nelems_orig,
- nelems_orig_merged = 0;
- FmgrInfo *mergeproc = sortproc;
- FmgrInfo crosstypeproc;
-
- Assert(skey->sk_strategy == BTEqualStrategyNumber);
- Assert(OidIsValid(origelemtype) && OidIsValid(nextelemtype));
-
- if (origelemtype != nextelemtype)
- {
- RegProcedure cmp_proc;
-
- /*
- * Cross-array-element-type merging is required, so can't just reuse
- * sortproc when merging
- */
- cmp_proc = get_opfamily_proc(rel->rd_opfamily[skey->sk_attno - 1],
- origelemtype, nextelemtype, BTORDER_PROC);
- if (!RegProcedureIsValid(cmp_proc))
- {
- /* Can't make the required comparisons */
- return false;
- }
-
- /* We have all we need to determine redundancy/contradictoriness */
- mergeproc = &crosstypeproc;
- fmgr_info_cxt(cmp_proc, mergeproc, so->arrayContext);
- }
-
- cxt.sortproc = mergeproc;
- cxt.collation = skey->sk_collation;
- cxt.reverse = reverse;
-
- for (int i = 0, j = 0; i < nelems_orig_start && j < nelems_next;)
- {
- Datum *oelem = elems_orig + i,
- *nelem = elems_next + j;
- int res = _bt_compare_array_elements(oelem, nelem, &cxt);
-
- if (res == 0)
- {
- elems_orig[nelems_orig_merged++] = *oelem;
- i++;
- j++;
- }
- else if (res < 0)
- i++;
- else /* res > 0 */
- j++;
- }
-
- *nelems_orig = nelems_orig_merged;
-
- return true;
-}
-
-/*
- * Compare an array scan key to a scalar scan key, eliminating contradictory
- * array elements such that the scalar scan key becomes redundant.
- *
- * Array elements can be eliminated as contradictory when excluded by some
- * other operator on the same attribute. For example, with an index scan qual
- * "WHERE a IN (1, 2, 3) AND a < 2", all array elements except the value "1"
- * are eliminated, and the < scan key is eliminated as redundant. Cases where
- * every array element is eliminated by a redundant scalar scan key have an
- * unsatisfiable qual, which we handle by setting *qual_ok=false for caller.
- *
- * If the opfamily doesn't supply a complete set of cross-type ORDER procs we
- * may not be able to determine which elements are contradictory. If we have
- * the required ORDER proc then we return true (and validly set *qual_ok),
- * guaranteeing that at least the scalar scan key can be considered redundant.
- * We return false if the comparison could not be made (caller must keep both
- * scan keys when this happens).
- */
-static bool
-_bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey,
- FmgrInfo *orderproc, BTArrayKeyInfo *array,
- bool *qual_ok)
-{
- Relation rel = scan->indexRelation;
- Oid opcintype = rel->rd_opcintype[arraysk->sk_attno - 1];
- int cmpresult = 0,
- cmpexact = 0,
- matchelem,
- new_nelems = 0;
- FmgrInfo crosstypeproc;
- FmgrInfo *orderprocp = orderproc;
-
- Assert(arraysk->sk_attno == skey->sk_attno);
- Assert(array->num_elems > 0);
- Assert(!(arraysk->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
- Assert((arraysk->sk_flags & SK_SEARCHARRAY) &&
- arraysk->sk_strategy == BTEqualStrategyNumber);
- Assert(!(skey->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
- Assert(!(skey->sk_flags & SK_SEARCHARRAY) ||
- skey->sk_strategy != BTEqualStrategyNumber);
-
- /*
- * _bt_binsrch_array_skey searches an array for the entry best matching a
- * datum of opclass input type for the index's attribute (on-disk type).
- * We can reuse the array's ORDER proc whenever the non-array scan key's
- * type is a match for the corresponding attribute's input opclass type.
- * Otherwise, we have to do another ORDER proc lookup so that our call to
- * _bt_binsrch_array_skey applies the correct comparator.
- *
- * Note: we have to support the convention that sk_subtype == InvalidOid
- * means the opclass input type; this is a hack to simplify life for
- * ScanKeyInit().
- */
- if (skey->sk_subtype != opcintype && skey->sk_subtype != InvalidOid)
- {
- RegProcedure cmp_proc;
- Oid arraysk_elemtype;
-
- /*
- * Need an ORDER proc lookup to detect redundancy/contradictoriness
- * with this pair of scankeys.
- *
- * Scalar scan key's argument will be passed to _bt_compare_array_skey
- * as its tupdatum/lefthand argument (rhs arg is for array elements).
- */
- arraysk_elemtype = arraysk->sk_subtype;
- if (arraysk_elemtype == InvalidOid)
- arraysk_elemtype = rel->rd_opcintype[arraysk->sk_attno - 1];
- cmp_proc = get_opfamily_proc(rel->rd_opfamily[arraysk->sk_attno - 1],
- skey->sk_subtype, arraysk_elemtype,
- BTORDER_PROC);
- if (!RegProcedureIsValid(cmp_proc))
- {
- /* Can't make the comparison */
- *qual_ok = false; /* suppress compiler
projects / users / c2main / postgres.git / commitdiff