+
+/*
+ * Derive type information from a relation attribute.
+ *
+ * This is needed for setting most slot statistics for all data types.
+ *
+ * This duplicates the logic in examine_attribute() but it will not skip the
+ * attribute if the attstattarget is 0.
+ *
+ * This information, retrieved from pg_attribute and pg_type with some
+ * specific handling for index expressions, is a prerequisite to calling
+ * any of the other statatt_*() functions.
+ */
+void
+statatt_get_type(Oid reloid, AttrNumber attnum,
+ Oid *atttypid, int32 *atttypmod,
+ char *atttyptype, Oid *atttypcoll,
+ Oid *eq_opr, Oid *lt_opr)
+{
+ Relation rel = relation_open(reloid, AccessShareLock);
+ Form_pg_attribute attr;
+ HeapTuple atup;
+ Node *expr;
+ TypeCacheEntry *typcache;
+
+ atup = SearchSysCache2(ATTNUM, ObjectIdGetDatum(reloid),
+ Int16GetDatum(attnum));
+
+ /* Attribute not found */
+ if (!HeapTupleIsValid(atup))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column %d of relation \"%s\" does not exist",
+ attnum, RelationGetRelationName(rel))));
+
+ attr = (Form_pg_attribute) GETSTRUCT(atup);
+
+ if (attr->attisdropped)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column %d of relation \"%s\" does not exist",
+ attnum, RelationGetRelationName(rel))));
+
+ expr = statatt_get_index_expr(rel, attr->attnum);
+
+ /*
+ * When analyzing an expression index, believe the expression tree's type
+ * not the column datatype --- the latter might be the opckeytype storage
+ * type of the opclass, which is not interesting for our purposes. This
+ * mimics the behavior of examine_attribute().
+ */
+ if (expr == NULL)
+ {
+ *atttypid = attr->atttypid;
+ *atttypmod = attr->atttypmod;
+ *atttypcoll = attr->attcollation;
+ }
+ else
+ {
+ *atttypid = exprType(expr);
+ *atttypmod = exprTypmod(expr);
+
+ if (OidIsValid(attr->attcollation))
+ *atttypcoll = attr->attcollation;
+ else
+ *atttypcoll = exprCollation(expr);
+ }
+ ReleaseSysCache(atup);
+
+ /*
+ * If it's a multirange, step down to the range type, as is done by
+ * multirange_typanalyze().
+ */
+ if (type_is_multirange(*atttypid))
+ *atttypid = get_multirange_range(*atttypid);
+
+ /* finds the right operators even if atttypid is a domain */
+ typcache = lookup_type_cache(*atttypid, TYPECACHE_LT_OPR | TYPECACHE_EQ_OPR);
+ *atttyptype = typcache->typtype;
+ *eq_opr = typcache->eq_opr;
+ *lt_opr = typcache->lt_opr;
+
+ /*
+ * Special case: collation for tsvector is DEFAULT_COLLATION_OID. See
+ * compute_tsvector_stats().
+ */
+ if (*atttypid == TSVECTOROID)
+ *atttypcoll = DEFAULT_COLLATION_OID;
+
+ relation_close(rel, NoLock);
+}
+
+/*
+ * Derive element type information from the attribute type. This information
+ * is needed when the given type is one that contains elements of other types.
+ *
+ * The atttypid and atttyptype should be derived from a previous call to
+ * statatt_get_type().
+ */
+bool
+statatt_get_elem_type(Oid atttypid, char atttyptype,
+ Oid *elemtypid, Oid *elem_eq_opr)
+{
+ TypeCacheEntry *elemtypcache;
+
+ if (atttypid == TSVECTOROID)
+ {
+ /*
+ * Special case: element type for tsvector is text. See
+ * compute_tsvector_stats().
+ */
+ *elemtypid = TEXTOID;
+ }
+ else
+ {
+ /* find underlying element type through any domain */
+ *elemtypid = get_base_element_type(atttypid);
+ }
+
+ if (!OidIsValid(*elemtypid))
+ return false;
+
+ /* finds the right operator even if elemtypid is a domain */
+ elemtypcache = lookup_type_cache(*elemtypid, TYPECACHE_EQ_OPR);
+ if (!OidIsValid(elemtypcache->eq_opr))
+ return false;
+
+ *elem_eq_opr = elemtypcache->eq_opr;
+
+ return true;
+}
+
+/*
+ * Build an array with element type elemtypid from a text datum, used as
+ * value of an attribute in a tuple to-be-inserted into pg_statistic.
+ *
+ * The typid and typmod should be derived from a previous call to
+ * statatt_get_type().
+ *
+ * If an error is encountered, capture it and throw a WARNING, with "ok" set
+ * to false. If the resulting array contains NULLs, raise a WARNING and
+ * set "ok" to false. When the operation succeeds, set "ok" to true.
+ */
+Datum
+statatt_build_stavalues(const char *staname, FmgrInfo *array_in, Datum d, Oid typid,
+ int32 typmod, bool *ok)
+{
+ LOCAL_FCINFO(fcinfo, 8);
+ char *s;
+ Datum result;
+ ErrorSaveContext escontext = {T_ErrorSaveContext};
+
+ escontext.details_wanted = true;
+
+ s = TextDatumGetCString(d);
+
+ InitFunctionCallInfoData(*fcinfo, array_in, 3, InvalidOid,
+ (Node *) &escontext, NULL);
+
+ fcinfo->args[0].value = CStringGetDatum(s);
+ fcinfo->args[0].isnull = false;
+ fcinfo->args[1].value = ObjectIdGetDatum(typid);
+ fcinfo->args[1].isnull = false;
+ fcinfo->args[2].value = Int32GetDatum(typmod);
+ fcinfo->args[2].isnull = false;
+
+ result = FunctionCallInvoke(fcinfo);
+
+ pfree(s);
+
+ if (escontext.error_occurred)
+ {
+ escontext.error_data->elevel = WARNING;
+ ThrowErrorData(escontext.error_data);
+ *ok = false;
+ return (Datum) 0;
+ }
+
+ if (array_contains_nulls(DatumGetArrayTypeP(result)))
+ {
+ ereport(WARNING,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("\"%s\" array must not contain null values", staname)));
+ *ok = false;
+ return (Datum) 0;
+ }
+
+ *ok = true;
+
+ return result;
+}
+
+/*
+ * Find and update the slot of a stakind, or use the first empty slot.
+ *
+ * Core statistics types expect the stakind value to be one of the
+ * STATISTIC_KIND_* constants defined in pg_statistic.h, but types defined
+ * by extensions are not restricted to those values.
+ *
+ * In the case of core statistics, the required staop is determined by the
+ * stakind given and will either be a hardcoded oid, or the eq/lt operator
+ * derived from statatt_get_type(). Likewise, types defined by extensions
+ * have no such restriction.
+ *
+ * The stacoll value should be either the atttypcoll derived from
+ * statatt_get_type(), or a harcoded value required by that particular
+ * stakind.
+ *
+ * The value/null pairs for stanumbers and stavalues should be calculated
+ * based on the stakind, using statatt_build_stavalues() or constructed arrays.
+ */
+void
+statatt_set_slot(Datum *values, bool *nulls, bool *replaces,
+ int16 stakind, Oid staop, Oid stacoll,
+ Datum stanumbers, bool stanumbers_isnull,
+ Datum stavalues, bool stavalues_isnull)
+{
+ int slotidx;
+ int first_empty = -1;
+ AttrNumber stakind_attnum;
+ AttrNumber staop_attnum;
+ AttrNumber stacoll_attnum;
+
+ /* find existing slot with given stakind */
+ for (slotidx = 0; slotidx < STATISTIC_NUM_SLOTS; slotidx++)
+ {
+ stakind_attnum = Anum_pg_statistic_stakind1 - 1 + slotidx;
+
+ if (first_empty < 0 &&
+ DatumGetInt16(values[stakind_attnum]) == 0)
+ first_empty = slotidx;
+ if (DatumGetInt16(values[stakind_attnum]) == stakind)
+ break;
+ }
+
+ if (slotidx >= STATISTIC_NUM_SLOTS && first_empty >= 0)
+ slotidx = first_empty;
+
+ if (slotidx >= STATISTIC_NUM_SLOTS)
+ ereport(ERROR,
+ (errmsg("maximum number of statistics slots exceeded: %d",
+ slotidx + 1)));
+
+ stakind_attnum = Anum_pg_statistic_stakind1 - 1 + slotidx;
+ staop_attnum = Anum_pg_statistic_staop1 - 1 + slotidx;
+ stacoll_attnum = Anum_pg_statistic_stacoll1 - 1 + slotidx;
+
+ if (DatumGetInt16(values[stakind_attnum]) != stakind)
+ {
+ values[stakind_attnum] = Int16GetDatum(stakind);
+ replaces[stakind_attnum] = true;
+ }
+ if (DatumGetObjectId(values[staop_attnum]) != staop)
+ {
+ values[staop_attnum] = ObjectIdGetDatum(staop);
+ replaces[staop_attnum] = true;
+ }
+ if (DatumGetObjectId(values[stacoll_attnum]) != stacoll)
+ {
+ values[stacoll_attnum] = ObjectIdGetDatum(stacoll);
+ replaces[stacoll_attnum] = true;
+ }
+ if (!stanumbers_isnull)
+ {
+ values[Anum_pg_statistic_stanumbers1 - 1 + slotidx] = stanumbers;
+ nulls[Anum_pg_statistic_stanumbers1 - 1 + slotidx] = false;
+ replaces[Anum_pg_statistic_stanumbers1 - 1 + slotidx] = true;
+ }
+ if (!stavalues_isnull)
+ {
+ values[Anum_pg_statistic_stavalues1 - 1 + slotidx] = stavalues;
+ nulls[Anum_pg_statistic_stavalues1 - 1 + slotidx] = false;
+ replaces[Anum_pg_statistic_stavalues1 - 1 + slotidx] = true;
+ }
+}
+
+/*
+ * Initialize values and nulls for a new pg_statistic tuple.
+ *
+ * The caller is responsible for allocating the arrays where the results are
+ * stored, which should be of size Natts_pg_statistic.
+ *
+ * When using this routine for a tuple inserted into pg_statistic, reloid,
+ * attnum and inherited flags should all be set.
+ *
+ * When using this routine for a tuple that is an element of a stxdexpr
+ * array inserted into pg_statistic_ext_data, reloid, attnum and inherited
+ * should be respectively set to InvalidOid, InvalidAttrNumber and false.
+ */
+void
+statatt_init_empty_tuple(Oid reloid, int16 attnum, bool inherited,
+ Datum *values, bool *nulls, bool *replaces)
+{
+ memset(nulls, true, sizeof(bool) * Natts_pg_statistic);
+ memset(replaces, true, sizeof(bool) * Natts_pg_statistic);
+
+ /* This must initialize non-NULL attributes */
+ values[Anum_pg_statistic_starelid - 1] = ObjectIdGetDatum(reloid);
+ nulls[Anum_pg_statistic_starelid - 1] = false;
+ values[Anum_pg_statistic_staattnum - 1] = Int16GetDatum(attnum);
+ nulls[Anum_pg_statistic_staattnum - 1] = false;
+ values[Anum_pg_statistic_stainherit - 1] = BoolGetDatum(inherited);
+ nulls[Anum_pg_statistic_stainherit - 1] = false;
+
+ values[Anum_pg_statistic_stanullfrac - 1] = DEFAULT_STATATT_NULL_FRAC;
+ nulls[Anum_pg_statistic_stanullfrac - 1] = false;
+ values[Anum_pg_statistic_stawidth - 1] = DEFAULT_STATATT_AVG_WIDTH;
+ nulls[Anum_pg_statistic_stawidth - 1] = false;
+ values[Anum_pg_statistic_stadistinct - 1] = DEFAULT_STATATT_N_DISTINCT;
+ nulls[Anum_pg_statistic_stadistinct - 1] = false;
+
+ /* initialize stakind, staop, and stacoll slots */
+ for (int slotnum = 0; slotnum < STATISTIC_NUM_SLOTS; slotnum++)
+ {
+ values[Anum_pg_statistic_stakind1 + slotnum - 1] = (Datum) 0;
+ nulls[Anum_pg_statistic_stakind1 + slotnum - 1] = false;
+ values[Anum_pg_statistic_staop1 + slotnum - 1] = ObjectIdGetDatum(InvalidOid);
+ nulls[Anum_pg_statistic_staop1 + slotnum - 1] = false;
+ values[Anum_pg_statistic_stacoll1 + slotnum - 1] = ObjectIdGetDatum(InvalidOid);
+ nulls[Anum_pg_statistic_stacoll1 + slotnum - 1] = false;
+ }
+}
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