# Create entries for variable-sized stats.
$node->safe_psql('postgres',
- q(select test_custom_stats_var_create('entry1')));
+ q(select test_custom_stats_var_create('entry1', 'Test entry 1')));
$node->safe_psql('postgres',
- q(select test_custom_stats_var_create('entry2')));
+ q(select test_custom_stats_var_create('entry2', 'Test entry 2')));
$node->safe_psql('postgres',
- q(select test_custom_stats_var_create('entry3')));
+ q(select test_custom_stats_var_create('entry3', 'Test entry 3')));
$node->safe_psql('postgres',
- q(select test_custom_stats_var_create('entry4')));
+ q(select test_custom_stats_var_create('entry4', 'Test entry 4')));
# Update counters: entry1=2, entry2=3, entry3=2, entry4=3, fixed=3
$node->safe_psql('postgres',
# Test data reports.
my $result = $node->safe_psql('postgres',
q(select * from test_custom_stats_var_report('entry1')));
-is($result, "entry1|2", "report for variable-sized data of entry1");
+is( $result,
+ "entry1|2|Test entry 1",
+ "report for variable-sized data of entry1");
+
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_var_report('entry2')));
-is($result, "entry2|3", "report for variable-sized data of entry2");
+is( $result,
+ "entry2|3|Test entry 2",
+ "report for variable-sized data of entry2");
+
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_var_report('entry3')));
-is($result, "entry3|2", "report for variable-sized data of entry3");
+is( $result,
+ "entry3|2|Test entry 3",
+ "report for variable-sized data of entry3");
+
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_var_report('entry4')));
-is($result, "entry4|3", "report for variable-sized data of entry4");
+is( $result,
+ "entry4|3|Test entry 4",
+ "report for variable-sized data of entry4");
+
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_fixed_report()));
is($result, "3|", "report for fixed-sized stats");
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_var_report('entry1')));
-is($result, "entry1|2", "variable-sized stats persist after clean restart");
+is( $result,
+ "entry1|2|Test entry 1",
+ "variable-sized stats persist after clean restart");
+
+$result = $node->safe_psql('postgres',
+ q(select * from test_custom_stats_var_report('entry2')));
+is( $result,
+ "entry2|3|Test entry 2",
+ "variable-sized stats persist after clean restart");
+
$result = $node->safe_psql('postgres',
q(select * from test_custom_stats_fixed_report()));
is($result, "3|", "fixed-sized stats persist after clean restart");
#include "common/hashfn.h"
#include "funcapi.h"
+#include "storage/dsm_registry.h"
#include "utils/builtins.h"
#include "utils/pgstat_internal.h"
.version = PG_VERSION
);
+#define TEST_CUSTOM_VAR_MAGIC_NUMBER (0xBEEFBEEF)
+
/*--------------------------------------------------------------------------
* Macros and constants
*--------------------------------------------------------------------------
*/
#define PGSTAT_KIND_TEST_CUSTOM_VAR_STATS 25
+/* File paths for auxiliary data serialization */
+#define TEST_CUSTOM_AUX_DATA_DESC "pg_stat/test_custom_var_stats_desc.stats"
+
/*
* Hash statistic name to generate entry index for pgstat lookup.
*/
{
PgStatShared_Common header; /* standard pgstat entry header */
PgStat_StatCustomVarEntry stats; /* custom statistics data */
+ dsa_pointer description; /* pointer to description string in DSA */
} PgStatShared_CustomVarEntry;
+/*--------------------------------------------------------------------------
+ * Global Variables
+ *--------------------------------------------------------------------------
+ */
+
+/* File handle for auxiliary data serialization */
+static FILE *fd_description = NULL;
+
+/* Current write offset in fd_description file */
+static pgoff_t fd_description_offset = 0;
+
+/* DSA area for storing variable-length description strings */
+static dsa_area *custom_stats_description_dsa = NULL;
+
/*--------------------------------------------------------------------------
* Function prototypes
*--------------------------------------------------------------------------
static bool test_custom_stats_var_flush_pending_cb(PgStat_EntryRef *entry_ref,
bool nowait);
+/* Serialization callback: write auxiliary entry data */
+static void test_custom_stats_var_to_serialized_data(const PgStat_HashKey *key,
+ const PgStatShared_Common *header,
+ FILE *statfile);
+
+/* Deserialization callback: read auxiliary entry data */
+static bool test_custom_stats_var_from_serialized_data(const PgStat_HashKey *key,
+ const PgStatShared_Common *header,
+ FILE *statfile);
+
+/* Finish callback: end of statistics file operations */
+static void test_custom_stats_var_finish(PgStat_StatsFileOp status);
+
/*--------------------------------------------------------------------------
* Custom kind configuration
*--------------------------------------------------------------------------
.shared_data_len = sizeof(((PgStatShared_CustomVarEntry *) 0)->stats),
.pending_size = sizeof(PgStat_StatCustomVarEntry),
.flush_pending_cb = test_custom_stats_var_flush_pending_cb,
+ .to_serialized_data = test_custom_stats_var_to_serialized_data,
+ .from_serialized_data = test_custom_stats_var_from_serialized_data,
+ .finish = test_custom_stats_var_finish,
};
/*--------------------------------------------------------------------------
return true;
}
+/*
+ * test_custom_stats_var_to_serialized_data() -
+ *
+ * Serialize auxiliary data (descriptions) for custom statistics entries
+ * to a secondary statistics file. This is called while writing the statistics
+ * to disk.
+ *
+ * This callback writes a mix of data within the main pgstats file and a
+ * secondary statistics file. The following data is written to the main file for
+ * each entry:
+ * - An arbitrary magic number.
+ * - An offset. This is used to know the location we need to look at
+ * to retrieve the information from the second file.
+ *
+ * The following data is written to the secondary statistics file:
+ * - The entry key, cross-checked with the data from the main file
+ * when reloaded.
+ * - The length of the description.
+ * - The description data itself.
+ */
+static void
+test_custom_stats_var_to_serialized_data(const PgStat_HashKey *key,
+ const PgStatShared_Common *header,
+ FILE *statfile)
+{
+ char *description;
+ size_t len;
+ PgStatShared_CustomVarEntry *entry = (PgStatShared_CustomVarEntry *) header;
+ bool found;
+ uint32 magic_number = TEST_CUSTOM_VAR_MAGIC_NUMBER;
+
+ /*
+ * First mark the main file with a magic number, keeping a trace that some
+ * auxiliary data will exist in the secondary statistics file.
+ */
+ pgstat_write_chunk_s(statfile, &magic_number);
+
+ /* Open statistics file for writing. */
+ if (!fd_description)
+ {
+ fd_description = AllocateFile(TEST_CUSTOM_AUX_DATA_DESC, PG_BINARY_W);
+ if (fd_description == NULL)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not open statistics file \"%s\" for writing: %m",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ return;
+ }
+
+ /* Initialize offset for secondary statistics file. */
+ fd_description_offset = 0;
+ }
+
+ /* Write offset to the main data file */
+ pgstat_write_chunk_s(statfile, &fd_description_offset);
+
+ /*
+ * First write the entry key to the secondary statistics file. This will
+ * be cross-checked with the key read from main stats file at loading
+ * time.
+ */
+ pgstat_write_chunk_s(fd_description, (PgStat_HashKey *) key);
+ fd_description_offset += sizeof(PgStat_HashKey);
+
+ if (!custom_stats_description_dsa)
+ custom_stats_description_dsa = GetNamedDSA("test_custom_stat_dsa", &found);
+
+ /* Handle entries without descriptions */
+ if (!DsaPointerIsValid(entry->description) || !custom_stats_description_dsa)
+ {
+ /* length to description file */
+ len = 0;
+ pgstat_write_chunk_s(fd_description, &len);
+ fd_description_offset += sizeof(size_t);
+ return;
+ }
+
+ /*
+ * Retrieve description from DSA, then write the length followed by the
+ * description.
+ */
+ description = dsa_get_address(custom_stats_description_dsa,
+ entry->description);
+ len = strlen(description) + 1;
+ pgstat_write_chunk_s(fd_description, &len);
+ pgstat_write_chunk(fd_description, description, len);
+
+ /*
+ * Update offset for next entry, counting for the length (size_t) of the
+ * description and the description contents.
+ */
+ fd_description_offset += len + sizeof(size_t);
+}
+
+/*
+ * test_custom_stats_var_from_serialized_data() -
+ *
+ * Read auxiliary data (descriptions) for custom statistics entries from
+ * the secondary statistics file. This is called while loading the statistics
+ * at startup.
+ *
+ * See the top of test_custom_stats_var_to_serialized_data() for a
+ * detailed description of the data layout read here.
+ */
+static bool
+test_custom_stats_var_from_serialized_data(const PgStat_HashKey *key,
+ const PgStatShared_Common *header,
+ FILE *statfile)
+{
+ PgStatShared_CustomVarEntry *entry;
+ dsa_pointer dp;
+ size_t len;
+ pgoff_t offset;
+ char *buffer;
+ bool found;
+ uint32 magic_number = 0;
+ PgStat_HashKey file_key;
+
+ /* Check the magic number first, in the main file. */
+ if (!pgstat_read_chunk_s(statfile, &magic_number))
+ {
+ elog(WARNING, "failed to read magic number from statistics file");
+ return false;
+ }
+
+ if (magic_number != TEST_CUSTOM_VAR_MAGIC_NUMBER)
+ {
+ elog(WARNING, "found magic number %u from statistics file, should be %u",
+ magic_number, TEST_CUSTOM_VAR_MAGIC_NUMBER);
+ return false;
+ }
+
+ /*
+ * Read the offset from the main stats file, to be able to read the
+ * auxiliary data from the secondary statistics file.
+ */
+ if (!pgstat_read_chunk_s(statfile, &offset))
+ {
+ elog(WARNING, "failed to read metadata offset from statistics file");
+ return false;
+ }
+
+ /* Open statistics file for reading if not already open */
+ if (!fd_description)
+ {
+ fd_description = AllocateFile(TEST_CUSTOM_AUX_DATA_DESC, PG_BINARY_R);
+ if (fd_description == NULL)
+ {
+ if (errno != ENOENT)
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not open statistics file \"%s\" for reading: %m",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ pgstat_reset_of_kind(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS);
+ return false;
+ }
+ }
+
+ /* Read data from the secondary statistics file, at the specified offset */
+ if (fseeko(fd_description, offset, SEEK_SET) != 0)
+ {
+ elog(WARNING, "failed to seek to offset %ld in description file", offset);
+ return false;
+ }
+
+ /* Read the hash key from the secondary statistics file */
+ if (!pgstat_read_chunk_s(fd_description, &file_key))
+ {
+ elog(WARNING, "failed to read hash key from file");
+ return false;
+ }
+
+ /* Check key consistency */
+ if (file_key.kind != key->kind ||
+ file_key.dboid != key->dboid ||
+ file_key.objid != key->objid)
+ {
+ elog(WARNING, "found entry key %u/%u/%" PRIu64 " not matching with %u/%u/%" PRIu64,
+ file_key.kind, file_key.dboid, file_key.objid,
+ key->kind, key->dboid, key->objid);
+ return false;
+ }
+
+ entry = (PgStatShared_CustomVarEntry *) header;
+
+ /* Read the description length and its data */
+ if (!pgstat_read_chunk_s(fd_description, &len))
+ {
+ elog(WARNING, "failed to read metadata length from statistics file");
+ return false;
+ }
+
+ /* Handle empty descriptions */
+ if (len == 0)
+ {
+ entry->description = InvalidDsaPointer;
+ return true;
+ }
+
+ /* Initialize DSA if needed */
+ if (!custom_stats_description_dsa)
+ custom_stats_description_dsa = GetNamedDSA("test_custom_stat_dsa", &found);
+
+ if (!custom_stats_description_dsa)
+ {
+ elog(WARNING, "could not access DSA for custom statistics descriptions");
+ return false;
+ }
+
+ buffer = palloc(len);
+ if (!pgstat_read_chunk(fd_description, buffer, len))
+ {
+ pfree(buffer);
+ elog(WARNING, "failed to read description from file");
+ return false;
+ }
+
+ /* Allocate space in DSA and copy the description */
+ dp = dsa_allocate(custom_stats_description_dsa, len);
+ memcpy(dsa_get_address(custom_stats_description_dsa, dp), buffer, len);
+ entry->description = dp;
+ pfree(buffer);
+
+ return true;
+}
+
+/*
+ * test_custom_stats_var_finish() -
+ *
+ * Cleanup function called at the end of statistics file operations.
+ * Handles closing files and cleanup based on the operation type.
+ */
+static void
+test_custom_stats_var_finish(PgStat_StatsFileOp status)
+{
+ switch (status)
+ {
+ case STATS_WRITE:
+ if (!fd_description)
+ return;
+
+ fd_description_offset = 0;
+
+ /* Check for write errors and cleanup if necessary */
+ if (ferror(fd_description))
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write to file \"%s\": %m",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ FreeFile(fd_description);
+ unlink(TEST_CUSTOM_AUX_DATA_DESC);
+ }
+ else if (FreeFile(fd_description) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not close file \"%s\": %m",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ unlink(TEST_CUSTOM_AUX_DATA_DESC);
+ }
+ break;
+
+ case STATS_READ:
+ if (fd_description)
+ FreeFile(fd_description);
+
+ /* Remove the file after reading */
+ elog(DEBUG2, "removing file \"%s\"", TEST_CUSTOM_AUX_DATA_DESC);
+ unlink(TEST_CUSTOM_AUX_DATA_DESC);
+ break;
+
+ case STATS_DISCARD:
+ {
+ int ret;
+
+ /* Attempt to remove the file */
+ ret = unlink(TEST_CUSTOM_AUX_DATA_DESC);
+ if (ret != 0)
+ {
+ if (errno == ENOENT)
+ elog(LOG,
+ "didn't need to unlink file \"%s\" - didn't exist",
+ TEST_CUSTOM_AUX_DATA_DESC);
+ else
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not unlink file \"%s\": %m",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ }
+ else
+ {
+ ereport(LOG,
+ (errmsg_internal("unlinked file \"%s\"",
+ TEST_CUSTOM_AUX_DATA_DESC)));
+ }
+ }
+ break;
+ }
+
+ fd_description = NULL;
+}
+
/*--------------------------------------------------------------------------
* Helper functions
*--------------------------------------------------------------------------
* test_custom_stats_var_create
* Create new custom statistic entry
*
- * Initializes a zero-valued statistics entry in shared memory.
- * Validates name length against NAMEDATALEN limit.
+ * Initializes a statistics entry with the given name and description.
*/
PG_FUNCTION_INFO_V1(test_custom_stats_var_create);
Datum
PgStat_EntryRef *entry_ref;
PgStatShared_CustomVarEntry *shared_entry;
char *stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+ char *description = text_to_cstring(PG_GETARG_TEXT_PP(1));
+ dsa_pointer dp = InvalidDsaPointer;
+ bool found;
/* Validate name length first */
if (strlen(stat_name) >= NAMEDATALEN)
errmsg("custom statistic name \"%s\" is too long", stat_name),
errdetail("Name must be less than %d characters.", NAMEDATALEN)));
+ /* Initialize DSA and description provided */
+ if (!custom_stats_description_dsa)
+ custom_stats_description_dsa = GetNamedDSA("test_custom_stat_dsa", &found);
+
+ if (!custom_stats_description_dsa)
+ ereport(ERROR,
+ (errmsg("could not access DSA for custom statistics descriptions")));
+
+ /* Allocate space in DSA and copy description */
+ dp = dsa_allocate(custom_stats_description_dsa, strlen(description) + 1);
+ memcpy(dsa_get_address(custom_stats_description_dsa, dp),
+ description,
+ strlen(description) + 1);
+
/* Create or get existing entry */
entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, InvalidOid,
PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name), true);
/* Zero-initialize statistics */
memset(&shared_entry->stats, 0, sizeof(shared_entry->stats));
+ /* Store description pointer */
+ shared_entry->description = dp;
+
pgstat_unlock_entry(entry_ref);
PG_RETURN_VOID();
* test_custom_stats_var_drop
* Remove custom statistic entry
*
- * Drops the named statistic from shared memory and requests
- * garbage collection if needed.
+ * Drops the named statistic from shared memory.
*/
PG_FUNCTION_INFO_V1(test_custom_stats_var_drop);
Datum
* test_custom_stats_var_report
* Retrieve custom statistic values
*
- * Returns single row with statistic name and call count if the
+ * Returns single row with statistic name, call count, and description if the
* statistic exists, otherwise returns no rows.
*/
PG_FUNCTION_INFO_V1(test_custom_stats_var_report);
if (funcctx->call_cntr < funcctx->max_calls)
{
- Datum values[2];
- bool nulls[2] = {false, false};
+ Datum values[3];
+ bool nulls[3] = {false, false, false};
HeapTuple tuple;
+ PgStat_EntryRef *entry_ref;
+ PgStatShared_CustomVarEntry *shared_entry;
+ char *description = NULL;
+ bool found;
stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
stat_entry = test_custom_stats_var_fetch_entry(stat_name);
/* Return row only if entry exists */
if (stat_entry)
{
+ /* Get entry ref to access shared entry */
+ entry_ref = pgstat_get_entry_ref(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, InvalidOid,
+ PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name), false, NULL);
+
+ if (entry_ref)
+ {
+ shared_entry = (PgStatShared_CustomVarEntry *) entry_ref->shared_stats;
+
+ /* Get description from DSA if available */
+ if (DsaPointerIsValid(shared_entry->description))
+ {
+ if (!custom_stats_description_dsa)
+ custom_stats_description_dsa = GetNamedDSA("test_custom_stat_dsa", &found);
+
+ if (custom_stats_description_dsa)
+ description = dsa_get_address(custom_stats_description_dsa, shared_entry->description);
+ }
+ }
+
values[0] = PointerGetDatum(cstring_to_text(stat_name));
values[1] = Int64GetDatum(stat_entry->numcalls);
+ if (description)
+ values[2] = PointerGetDatum(cstring_to_text(description));
+ else
+ nulls[2] = true;
+
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
}
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