and the number of times the background writer stopped a cleaning scan
because it had written too many buffers. Also includes
statistics about the shared buffer pool, including buffers written
- by backends (that is, not by the background writer) and total buffers
- allocated.
+ by backends (that is, not by the background writer), how many times
+ those backends had to execute their own fsync calls (normally the
+ background writer handles those even when the backend does its own
+ write), and total buffers allocated.
</entry>
</row>
pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean,
pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean,
pg_stat_get_buf_written_backend() AS buffers_backend,
+ pg_stat_get_buf_fsync_backend() AS buffers_backend_fsync,
pg_stat_get_buf_alloc() AS buffers_alloc;
CREATE VIEW pg_user_mappings AS
*
* num_backend_writes is used to count the number of buffer writes performed
* by non-bgwriter processes. This counter should be wide enough that it
- * can't overflow during a single bgwriter cycle.
+ * can't overflow during a single bgwriter cycle. num_backend_fsync
+ * counts the subset of those writes that also had to do their own fsync,
+ * because the background writer failed to absorb their request.
*
* The requests array holds fsync requests sent by backends and not yet
* absorbed by the bgwriter.
*
- * Unlike the checkpoint fields, num_backend_writes and the requests
- * fields are protected by BgWriterCommLock.
+ * Unlike the checkpoint fields, num_backend_writes, num_backend_fsync, and
+ * the requests fields are protected by BgWriterCommLock.
*----------
*/
typedef struct
int ckpt_flags; /* checkpoint flags, as defined in xlog.h */
uint32 num_backend_writes; /* counts non-bgwriter buffer writes */
+ uint32 num_backend_fsync; /* counts non-bgwriter fsync calls */
int num_requests; /* current # of requests */
int max_requests; /* allocated array size */
LWLockAcquire(BgWriterCommLock, LW_EXCLUSIVE);
- /* we count non-bgwriter writes even when the request queue overflows */
+ /* Count all backend writes regardless of if they fit in the queue */
BgWriterShmem->num_backend_writes++;
if (BgWriterShmem->bgwriter_pid == 0 ||
BgWriterShmem->num_requests >= BgWriterShmem->max_requests)
{
+ /* Also count the subset where backends have to do their own fsync */
+ BgWriterShmem->num_backend_fsync++;
LWLockRelease(BgWriterCommLock);
return false;
}
/* Transfer write count into pending pgstats message */
BgWriterStats.m_buf_written_backend += BgWriterShmem->num_backend_writes;
+ BgWriterStats.m_buf_fsync_backend += BgWriterShmem->num_backend_fsync;
+
BgWriterShmem->num_backend_writes = 0;
+ BgWriterShmem->num_backend_fsync = 0;
n = BgWriterShmem->num_requests;
if (n > 0)
globalStats.buf_written_clean += msg->m_buf_written_clean;
globalStats.maxwritten_clean += msg->m_maxwritten_clean;
globalStats.buf_written_backend += msg->m_buf_written_backend;
+ globalStats.buf_fsync_backend += msg->m_buf_fsync_backend;
globalStats.buf_alloc += msg->m_buf_alloc;
}
if (ForwardFsyncRequest(reln->smgr_rnode, forknum, seg->mdfd_segno))
return; /* passed it off successfully */
+ ereport(DEBUG1,
+ (errmsg("could not forward fsync request because request queue is full")));
+
if (FileSync(seg->mdfd_vfd) < 0)
ereport(ERROR,
(errcode_for_file_access(),
extern Datum pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_bgwriter_maxwritten_clean(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_buf_written_backend(PG_FUNCTION_ARGS);
+extern Datum pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_buf_alloc(PG_FUNCTION_ARGS);
extern Datum pg_stat_get_xact_numscans(PG_FUNCTION_ARGS);
}
Datum
+pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS)
+{
+ PG_RETURN_INT64(pgstat_fetch_global()->buf_fsync_backend);
+}
+
+Datum
pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
{
PG_RETURN_INT64(pgstat_fetch_global()->buf_alloc);
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 201011091
+#define CATALOG_VERSION_NO 201011151
#endif
DESCR("statistics: number of times the bgwriter stopped processing when it had written too many buffers while cleaning");
DATA(insert OID = 2775 ( pg_stat_get_buf_written_backend PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_buf_written_backend _null_ _null_ _null_ ));
DESCR("statistics: number of buffers written by backends");
+DATA(insert OID = 3063 ( pg_stat_get_buf_fsync_backend PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_buf_fsync_backend _null_ _null_ _null_ ));
+DESCR("statistics: number of backend buffer writes that did their own fsync");
DATA(insert OID = 2859 ( pg_stat_get_buf_alloc PGNSP PGUID 12 1 0 0 f f f t f s 0 0 20 "" _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
DESCR("statistics: number of buffer allocations");
PgStat_Counter m_buf_written_clean;
PgStat_Counter m_maxwritten_clean;
PgStat_Counter m_buf_written_backend;
+ PgStat_Counter m_buf_fsync_backend;
PgStat_Counter m_buf_alloc;
} PgStat_MsgBgWriter;
PgStat_Counter buf_written_clean;
PgStat_Counter maxwritten_clean;
PgStat_Counter buf_written_backend;
+ PgStat_Counter buf_fsync_backend;
PgStat_Counter buf_alloc;
} PgStat_GlobalStats;
pg_stat_activity | SELECT s.datid, d.datname, s.procpid, s.usesysid, u.rolname AS usename, s.application_name, s.client_addr, s.client_port, s.backend_start, s.xact_start, s.query_start, s.waiting, s.current_query FROM pg_database d, pg_stat_get_activity(NULL::integer) s(datid, procpid, usesysid, application_name, current_query, waiting, xact_start, query_start, backend_start, client_addr, client_port), pg_authid u WHERE ((s.datid = d.oid) AND (s.usesysid = u.oid));
pg_stat_all_indexes | SELECT c.oid AS relid, i.oid AS indexrelid, n.nspname AS schemaname, c.relname, i.relname AS indexrelname, pg_stat_get_numscans(i.oid) AS idx_scan, pg_stat_get_tuples_returned(i.oid) AS idx_tup_read, pg_stat_get_tuples_fetched(i.oid) AS idx_tup_fetch FROM (((pg_class c JOIN pg_index x ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (c.relkind = ANY (ARRAY['r'::"char", 't'::"char"]));
pg_stat_all_tables | SELECT c.oid AS relid, n.nspname AS schemaname, c.relname, pg_stat_get_numscans(c.oid) AS seq_scan, pg_stat_get_tuples_returned(c.oid) AS seq_tup_read, (sum(pg_stat_get_numscans(i.indexrelid)))::bigint AS idx_scan, ((sum(pg_stat_get_tuples_fetched(i.indexrelid)))::bigint + pg_stat_get_tuples_fetched(c.oid)) AS idx_tup_fetch, pg_stat_get_tuples_inserted(c.oid) AS n_tup_ins, pg_stat_get_tuples_updated(c.oid) AS n_tup_upd, pg_stat_get_tuples_deleted(c.oid) AS n_tup_del, pg_stat_get_tuples_hot_updated(c.oid) AS n_tup_hot_upd, pg_stat_get_live_tuples(c.oid) AS n_live_tup, pg_stat_get_dead_tuples(c.oid) AS n_dead_tup, pg_stat_get_last_vacuum_time(c.oid) AS last_vacuum, pg_stat_get_last_autovacuum_time(c.oid) AS last_autovacuum, pg_stat_get_last_analyze_time(c.oid) AS last_analyze, pg_stat_get_last_autoanalyze_time(c.oid) AS last_autoanalyze, pg_stat_get_vacuum_count(c.oid) AS vacuum_count, pg_stat_get_autovacuum_count(c.oid) AS autovacuum_count, pg_stat_get_analyze_count(c.oid) AS analyze_count, pg_stat_get_autoanalyze_count(c.oid) AS autoanalyze_count FROM ((pg_class c LEFT JOIN pg_index i ON ((c.oid = i.indrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (c.relkind = ANY (ARRAY['r'::"char", 't'::"char"])) GROUP BY c.oid, n.nspname, c.relname;
- pg_stat_bgwriter | SELECT pg_stat_get_bgwriter_timed_checkpoints() AS checkpoints_timed, pg_stat_get_bgwriter_requested_checkpoints() AS checkpoints_req, pg_stat_get_bgwriter_buf_written_checkpoints() AS buffers_checkpoint, pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_written_backend() AS buffers_backend, pg_stat_get_buf_alloc() AS buffers_alloc;
+ pg_stat_bgwriter | SELECT pg_stat_get_bgwriter_timed_checkpoints() AS checkpoints_timed, pg_stat_get_bgwriter_requested_checkpoints() AS checkpoints_req, pg_stat_get_bgwriter_buf_written_checkpoints() AS buffers_checkpoint, pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_written_backend() AS buffers_backend, pg_stat_get_buf_fsync_backend() AS buffers_backend_fsync, pg_stat_get_buf_alloc() AS buffers_alloc;
pg_stat_database | SELECT d.oid AS datid, d.datname, pg_stat_get_db_numbackends(d.oid) AS numbackends, pg_stat_get_db_xact_commit(d.oid) AS xact_commit, pg_stat_get_db_xact_rollback(d.oid) AS xact_rollback, (pg_stat_get_db_blocks_fetched(d.oid) - pg_stat_get_db_blocks_hit(d.oid)) AS blks_read, pg_stat_get_db_blocks_hit(d.oid) AS blks_hit, pg_stat_get_db_tuples_returned(d.oid) AS tup_returned, pg_stat_get_db_tuples_fetched(d.oid) AS tup_fetched, pg_stat_get_db_tuples_inserted(d.oid) AS tup_inserted, pg_stat_get_db_tuples_updated(d.oid) AS tup_updated, pg_stat_get_db_tuples_deleted(d.oid) AS tup_deleted FROM pg_database d;
pg_stat_sys_indexes | SELECT pg_stat_all_indexes.relid, pg_stat_all_indexes.indexrelid, pg_stat_all_indexes.schemaname, pg_stat_all_indexes.relname, pg_stat_all_indexes.indexrelname, pg_stat_all_indexes.idx_scan, pg_stat_all_indexes.idx_tup_read, pg_stat_all_indexes.idx_tup_fetch FROM pg_stat_all_indexes WHERE ((pg_stat_all_indexes.schemaname = ANY (ARRAY['pg_catalog'::name, 'information_schema'::name])) OR (pg_stat_all_indexes.schemaname ~ '^pg_toast'::text));
pg_stat_sys_tables | SELECT pg_stat_all_tables.relid, pg_stat_all_tables.schemaname, pg_stat_all_tables.relname, pg_stat_all_tables.seq_scan, pg_stat_all_tables.seq_tup_read, pg_stat_all_tables.idx_scan, pg_stat_all_tables.idx_tup_fetch, pg_stat_all_tables.n_tup_ins, pg_stat_all_tables.n_tup_upd, pg_stat_all_tables.n_tup_del, pg_stat_all_tables.n_tup_hot_upd, pg_stat_all_tables.n_live_tup, pg_stat_all_tables.n_dead_tup, pg_stat_all_tables.last_vacuum, pg_stat_all_tables.last_autovacuum, pg_stat_all_tables.last_analyze, pg_stat_all_tables.last_autoanalyze, pg_stat_all_tables.vacuum_count, pg_stat_all_tables.autovacuum_count, pg_stat_all_tables.analyze_count, pg_stat_all_tables.autoanalyze_count FROM pg_stat_all_tables WHERE ((pg_stat_all_tables.schemaname = ANY (ARRAY['pg_catalog'::name, 'information_schema'::name])) OR (pg_stat_all_tables.schemaname ~ '^pg_toast'::text));
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