Adding upstream version 15.4.upstream/15.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 243 insertions, 0 deletions

diff --git a/src/backend/utils/activity/pgstat_function.c b/src/backend/utils/activity/pgstat_function.c
new file mode 100644
index 0000000..427d8c4
--- /dev/null
+++ b/src/backend/utils/activity/pgstat_function.c
@@ -0,0 +1,243 @@
+/* -------------------------------------------------------------------------
+ *
+ * pgstat_function.c
+ *	  Implementation of function statistics.
+ *
+ * This file contains the implementation of function statistics. It is kept
+ * separate from pgstat.c to enforce the line between the statistics access /
+ * storage implementation and the details about individual types of
+ * statistics.
+ *
+ * Copyright (c) 2001-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  src/backend/utils/activity/pgstat_function.c
+ * -------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "utils/inval.h"
+#include "utils/pgstat_internal.h"
+#include "utils/syscache.h"
+
+
+/* ----------
+ * GUC parameters
+ * ----------
+ */
+int			pgstat_track_functions = TRACK_FUNC_OFF;
+
+
+/*
+ * Total time charged to functions so far in the current backend.
+ * We use this to help separate "self" and "other" time charges.
+ * (We assume this initializes to zero.)
+ */
+static instr_time total_func_time;
+
+
+/*
+ * Ensure that stats are dropped if transaction aborts.
+ */
+void
+pgstat_create_function(Oid proid)
+{
+	pgstat_create_transactional(PGSTAT_KIND_FUNCTION,
+								MyDatabaseId,
+								proid);
+}
+
+/*
+ * Ensure that stats are dropped if transaction commits.
+ *
+ * NB: This is only reliable because pgstat_init_function_usage() does some
+ * extra work. If other places start emitting function stats they likely need
+ * similar logic.
+ */
+void
+pgstat_drop_function(Oid proid)
+{
+	pgstat_drop_transactional(PGSTAT_KIND_FUNCTION,
+							  MyDatabaseId,
+							  proid);
+}
+
+/*
+ * Initialize function call usage data.
+ * Called by the executor before invoking a function.
+ */
+void
+pgstat_init_function_usage(FunctionCallInfo fcinfo,
+						   PgStat_FunctionCallUsage *fcu)
+{
+	PgStat_EntryRef *entry_ref;
+	PgStat_BackendFunctionEntry *pending;
+	bool		created_entry;
+
+	if (pgstat_track_functions <= fcinfo->flinfo->fn_stats)
+	{
+		/* stats not wanted */
+		fcu->fs = NULL;
+		return;
+	}
+
+	entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_FUNCTION,
+										  MyDatabaseId,
+										  fcinfo->flinfo->fn_oid,
+										  &created_entry);
+
+	/*
+	 * If no shared entry already exists, check if the function has been
+	 * deleted concurrently. This can go unnoticed until here because
+	 * executing a statement that just calls a function, does not trigger
+	 * cache invalidation processing. The reason we care about this case is
+	 * that otherwise we could create a new stats entry for an already dropped
+	 * function (for relations etc this is not possible because emitting stats
+	 * requires a lock for the relation to already have been acquired).
+	 *
+	 * It's somewhat ugly to have a behavioral difference based on
+	 * track_functions being enabled/disabled. But it seems acceptable, given
+	 * that there's already behavioral differences depending on whether the
+	 * function is the caches etc.
+	 *
+	 * For correctness it'd be sufficient to set ->dropped to true. However,
+	 * the accepted invalidation will commonly cause "low level" failures in
+	 * PL code, with an OID in the error message. Making this harder to
+	 * test...
+	 */
+	if (created_entry)
+	{
+		AcceptInvalidationMessages();
+		if (!SearchSysCacheExists1(PROCOID, ObjectIdGetDatum(fcinfo->flinfo->fn_oid)))
+		{
+			pgstat_drop_entry(PGSTAT_KIND_FUNCTION, MyDatabaseId,
+							  fcinfo->flinfo->fn_oid);
+			ereport(ERROR, errcode(ERRCODE_UNDEFINED_FUNCTION),
+					errmsg("function call to dropped function"));
+		}
+	}
+
+	pending = entry_ref->pending;
+
+	fcu->fs = &pending->f_counts;
+
+	/* save stats for this function, later used to compensate for recursion */
+	fcu->save_f_total_time = pending->f_counts.f_total_time;
+
+	/* save current backend-wide total time */
+	fcu->save_total = total_func_time;
+
+	/* get clock time as of function start */
+	INSTR_TIME_SET_CURRENT(fcu->f_start);
+}
+
+/*
+ * Calculate function call usage and update stat counters.
+ * Called by the executor after invoking a function.
+ *
+ * In the case of a set-returning function that runs in value-per-call mode,
+ * we will see multiple pgstat_init_function_usage/pgstat_end_function_usage
+ * calls for what the user considers a single call of the function.  The
+ * finalize flag should be TRUE on the last call.
+ */
+void
+pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu, bool finalize)
+{
+	PgStat_FunctionCounts *fs = fcu->fs;
+	instr_time	f_total;
+	instr_time	f_others;
+	instr_time	f_self;
+
+	/* stats not wanted? */
+	if (fs == NULL)
+		return;
+
+	/* total elapsed time in this function call */
+	INSTR_TIME_SET_CURRENT(f_total);
+	INSTR_TIME_SUBTRACT(f_total, fcu->f_start);
+
+	/* self usage: elapsed minus anything already charged to other calls */
+	f_others = total_func_time;
+	INSTR_TIME_SUBTRACT(f_others, fcu->save_total);
+	f_self = f_total;
+	INSTR_TIME_SUBTRACT(f_self, f_others);
+
+	/* update backend-wide total time */
+	INSTR_TIME_ADD(total_func_time, f_self);
+
+	/*
+	 * Compute the new f_total_time as the total elapsed time added to the
+	 * pre-call value of f_total_time.  This is necessary to avoid
+	 * double-counting any time taken by recursive calls of myself.  (We do
+	 * not need any similar kluge for self time, since that already excludes
+	 * any recursive calls.)
+	 */
+	INSTR_TIME_ADD(f_total, fcu->save_f_total_time);
+
+	/* update counters in function stats table */
+	if (finalize)
+		fs->f_numcalls++;
+	fs->f_total_time = f_total;
+	INSTR_TIME_ADD(fs->f_self_time, f_self);
+}
+
+/*
+ * Flush out pending stats for the entry
+ *
+ * If nowait is true, this function returns false if lock could not
+ * immediately acquired, otherwise true is returned.
+ */
+bool
+pgstat_function_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
+{
+	PgStat_BackendFunctionEntry *localent;
+	PgStatShared_Function *shfuncent;
+
+	localent = (PgStat_BackendFunctionEntry *) entry_ref->pending;
+	shfuncent = (PgStatShared_Function *) entry_ref->shared_stats;
+
+	/* localent always has non-zero content */
+
+	if (!pgstat_lock_entry(entry_ref, nowait))
+		return false;
+
+	shfuncent->stats.f_numcalls += localent->f_counts.f_numcalls;
+	shfuncent->stats.f_total_time +=
+		INSTR_TIME_GET_MICROSEC(localent->f_counts.f_total_time);
+	shfuncent->stats.f_self_time +=
+		INSTR_TIME_GET_MICROSEC(localent->f_counts.f_self_time);
+
+	pgstat_unlock_entry(entry_ref);
+
+	return true;
+}
+
+/*
+ * find any existing PgStat_BackendFunctionEntry entry for specified function
+ *
+ * If no entry, return NULL, don't create a new one
+ */
+PgStat_BackendFunctionEntry *
+find_funcstat_entry(Oid func_id)
+{
+	PgStat_EntryRef *entry_ref;
+
+	entry_ref = pgstat_fetch_pending_entry(PGSTAT_KIND_FUNCTION, MyDatabaseId, func_id);
+
+	if (entry_ref)
+		return entry_ref->pending;
+	return NULL;
+}
+
+/*
+ * Support function for the SQL-callable pgstat* functions. Returns
+ * the collected statistics for one function or NULL.
+ */
+PgStat_StatFuncEntry *
+pgstat_fetch_stat_funcentry(Oid func_id)
+{
+	return (PgStat_StatFuncEntry *)
+		pgstat_fetch_entry(PGSTAT_KIND_FUNCTION, MyDatabaseId, func_id);
+}