Thanks for the review!
On Tue, Feb 28, 2023 at 4:49 AM Drouvot, Bertrand
<bertranddrouvot...@gmail.com> wrote:
> On 2/26/23 5:03 PM, Melanie Plageman wrote:
> > As suggested in [1], the attached patch adds IO times to pg_stat_io;
>
> Thanks for the patch!
>
> I started to have a look at it and figured out that a tiny rebase was needed
> (due to
> 728560db7d and b9f0e54bc9), so please find the rebase (aka V2) attached.
Thanks for doing that!
> > The timings will only be non-zero when track_io_timing is on
>
> That could lead to incorrect interpretation if one wants to divide the timing
> per operations, say:
>
> - track_io_timing is set to on while there is already operations
> - or set to off while it was on (and the number of operations keeps growing)
>
> Might be worth to warn/highlight in the "track_io_timing" doc?
This is a good point. I've added a note to the docs for pg_stat_io.
> + if (track_io_timing)
> + {
> + INSTR_TIME_SET_CURRENT(io_time);
> + INSTR_TIME_SUBTRACT(io_time, io_start);
> + pgstat_count_io_time(io_object, io_context,
> IOOP_EXTEND, io_time);
> + }
> +
> +
> pgstat_count_io_op(io_object, io_context, IOOP_EXTEND);
>
> vs
>
> @@ -1042,6 +1059,7 @@ ReadBuffer_common(SMgrRelation smgr, char
> relpersistence, ForkNumber forkNum,
> INSTR_TIME_SUBTRACT(io_time, io_start);
>
> pgstat_count_buffer_read_time(INSTR_TIME_GET_MICROSEC(io_time));
> INSTR_TIME_ADD(pgBufferUsage.blk_read_time,
> io_time);
> + pgstat_count_io_time(io_object, io_context,
> IOOP_READ, io_time);
> }
>
> That leads to pgstat_count_io_time() to be called before pgstat_count_io_op()
> (for the IOOP_EXTEND case) and
> after pgstat_count_io_op() (for the IOOP_READ case).
>
> What about calling them in the same order and so that pgstat_count_io_time()
> is called before pgstat_count_io_op()?
>
> If so, the ordering would also need to be changed in:
>
> - FlushRelationBuffers()
> - register_dirty_segment()
Yes, good point. I've updated the code to use this suggested ordering in
attached v3.
> > There is one minor question (in the code as a TODO) which is whether or
> > not it is worth cross-checking that IO counts and times are either both
> > zero or neither zero in the validation function
> > pgstat_bktype_io_stats_valid().
> >
>
> As pgstat_bktype_io_stats_valid() is called only in Assert(), I think that
> would be a good idea
> to also check that if counts are not Zero then times are not Zero.
Yes, I think adding some validation around the relationship between
counts and timing should help prevent developers from forgetting to call
pg_stat_count_io_op() when calling pgstat_count_io_time() (as relevant).
However, I think that we cannot check that if IO counts are non-zero
that IO times are non-zero, because the user may not have
track_io_timing enabled. We can check that if IO times are not zero, IO
counts are not zero. I've done this in the attached v3.
- Melanie
From 52d997001108a52c833b339f9b8dcb3d34ed3270 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplage...@gmail.com>
Date: Mon, 6 Mar 2023 10:41:51 -0500
Subject: [PATCH v3] Track IO times in pg_stat_io
Add IO timing for reads, writes, extends, and fsyncs to pg_stat_io.
Reviewed-by: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/CAAKRu_ay5iKmnbXZ3DsauViF3eMxu4m1oNnJXqV_HyqYeg55Ww%40mail.gmail.com
---
doc/src/sgml/monitoring.sgml | 59 ++++++++++++++++
src/backend/catalog/system_views.sql | 4 ++
src/backend/storage/buffer/bufmgr.c | 40 +++++++++--
src/backend/storage/buffer/localbuf.c | 14 ++++
src/backend/storage/smgr/md.c | 47 ++++++++++---
src/backend/utils/activity/pgstat_io.c | 96 +++++++++++++++++++++-----
src/backend/utils/adt/pgstatfuncs.c | 40 +++++++++--
src/include/catalog/pg_proc.dat | 6 +-
src/include/pgstat.h | 5 +-
src/test/regress/expected/rules.out | 6 +-
10 files changed, 275 insertions(+), 42 deletions(-)
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 6249bb50d0..ad3667f258 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -3814,6 +3814,18 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</entry>
</row>
+ <row>
+ <entry role="catalog_table_entry">
+ <para role="column_definition">
+ <structfield>read_time</structfield> <type>double precision</type>
+ </para>
+ <para>
+ Time spent in read operations in milliseconds (if <xref
+ linkend="guc-track-io-timing"/> is enabled, otherwise zero)
+ </para>
+ </entry>
+ </row>
+
<row>
<entry role="catalog_table_entry">
<para role="column_definition">
@@ -3826,6 +3838,18 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</entry>
</row>
+ <row>
+ <entry role="catalog_table_entry">
+ <para role="column_definition">
+ <structfield>write_time</structfield> <type>double precision</type>
+ </para>
+ <para>
+ Time spent in write operations in milliseconds (if <xref
+ linkend="guc-track-io-timing"/> is enabled, otherwise zero)
+ </para>
+ </entry>
+ </row>
+
<row>
<entry role="catalog_table_entry">
<para role="column_definition">
@@ -3838,6 +3862,18 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</entry>
</row>
+ <row>
+ <entry role="catalog_table_entry">
+ <para role="column_definition">
+ <structfield>extend_time</structfield> <type>double precision</type>
+ </para>
+ <para>
+ Time spent in extend operations in milliseconds (if <xref
+ linkend="guc-track-io-timing"/> is enabled, otherwise zero)
+ </para>
+ </entry>
+ </row>
+
<row>
<entry role="catalog_table_entry">
<para role="column_definition">
@@ -3902,6 +3938,18 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</entry>
</row>
+ <row>
+ <entry role="catalog_table_entry">
+ <para role="column_definition">
+ <structfield>fsync_time</structfield> <type>double precision</type>
+ </para>
+ <para>
+ Time spent in fsync operations in milliseconds (if <xref
+ linkend="guc-track-io-timing"/> is enabled, otherwise zero)
+ </para>
+ </entry>
+ </row>
+
<row>
<entry role="catalog_table_entry">
<para role="column_definition">
@@ -3967,6 +4015,17 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</itemizedlist>
</para>
+ <note>
+ <para>
+ Columns tracking I/O time will only be non-zero when <xref
+ linkend="guc-track-io-timing"/> is enabled. The user should be careful when
+ using these columns in combination with their corresponding operations to
+ ensure that <varname>track_io_timing</varname> was enabled for the entire
+ time since the last reset.
+ </para>
+ </note>
+
+
</sect2>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 34ca0e739f..39391bc2fc 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1123,12 +1123,16 @@ SELECT
b.io_object,
b.io_context,
b.reads,
+ b.read_time,
b.writes,
+ b.write_time,
b.extends,
+ b.extend_time,
b.op_bytes,
b.evictions,
b.reuses,
b.fsyncs,
+ b.fsync_time,
b.stats_reset
FROM pg_stat_get_io() b;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 0a05577b68..91aa52848a 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1000,11 +1000,27 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
if (isExtend)
{
+ instr_time io_start,
+ io_time;
+
/* new buffers are zero-filled */
MemSet((char *) bufBlock, 0, BLCKSZ);
+
+ if (track_io_timing)
+ INSTR_TIME_SET_CURRENT(io_start);
+ else
+ INSTR_TIME_SET_ZERO(io_start);
+
/* don't set checksum for all-zero page */
smgrextend(smgr, forkNum, blockNum, bufBlock, false);
+ if (track_io_timing)
+ {
+ INSTR_TIME_SET_CURRENT(io_time);
+ INSTR_TIME_SUBTRACT(io_time, io_start);
+ pgstat_count_io_time(io_object, io_context, IOOP_EXTEND, io_time);
+ }
+
pgstat_count_io_op(io_object, io_context, IOOP_EXTEND);
/*
@@ -1034,16 +1050,17 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
smgrread(smgr, forkNum, blockNum, bufBlock);
- pgstat_count_io_op(io_object, io_context, IOOP_READ);
-
if (track_io_timing)
{
INSTR_TIME_SET_CURRENT(io_time);
INSTR_TIME_SUBTRACT(io_time, io_start);
pgstat_count_buffer_read_time(INSTR_TIME_GET_MICROSEC(io_time));
INSTR_TIME_ADD(pgBufferUsage.blk_read_time, io_time);
+ pgstat_count_io_time(io_object, io_context, IOOP_READ, io_time);
}
+ pgstat_count_io_op(io_object, io_context, IOOP_READ);
+
/* check for garbage data */
if (!PageIsVerifiedExtended((Page) bufBlock, blockNum,
PIV_LOG_WARNING | PIV_REPORT_STAT))
@@ -2981,16 +2998,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
* When a strategy is not in use, the write can only be a "regular" write
* of a dirty shared buffer (IOCONTEXT_NORMAL IOOP_WRITE).
*/
- pgstat_count_io_op(IOOBJECT_RELATION, io_context, IOOP_WRITE);
-
if (track_io_timing)
{
INSTR_TIME_SET_CURRENT(io_time);
INSTR_TIME_SUBTRACT(io_time, io_start);
pgstat_count_buffer_write_time(INSTR_TIME_GET_MICROSEC(io_time));
INSTR_TIME_ADD(pgBufferUsage.blk_write_time, io_time);
+ pgstat_count_io_time(IOOBJECT_RELATION, io_context, IOOP_WRITE, io_time);
}
+ pgstat_count_io_op(IOOBJECT_RELATION, io_context, IOOP_WRITE);
pgBufferUsage.shared_blks_written++;
/*
@@ -3594,6 +3611,9 @@ FlushRelationBuffers(Relation rel)
if (RelationUsesLocalBuffers(rel))
{
+ instr_time io_start,
+ io_time;
+
for (i = 0; i < NLocBuffer; i++)
{
uint32 buf_state;
@@ -3616,6 +3636,11 @@ FlushRelationBuffers(Relation rel)
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
+ if (track_io_timing)
+ INSTR_TIME_SET_CURRENT(io_start);
+ else
+ INSTR_TIME_SET_ZERO(io_start);
+
smgrwrite(RelationGetSmgr(rel),
BufTagGetForkNum(&bufHdr->tag),
bufHdr->tag.blockNum,
@@ -3625,6 +3650,13 @@ FlushRelationBuffers(Relation rel)
buf_state &= ~(BM_DIRTY | BM_JUST_DIRTIED);
pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+ if (track_io_timing)
+ {
+ INSTR_TIME_SET_CURRENT(io_time);
+ INSTR_TIME_SUBTRACT(io_time, io_start);
+ pgstat_count_io_time(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_WRITE, io_time);
+ }
+
pgstat_count_io_op(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_WRITE);
/* Pop the error context stack */
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 5325ddb663..b1272840bd 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -220,6 +220,8 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
*/
if (buf_state & BM_DIRTY)
{
+ instr_time io_start,
+ io_time;
SMgrRelation oreln;
Page localpage = (char *) LocalBufHdrGetBlock(bufHdr);
@@ -228,6 +230,11 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
+ if (track_io_timing)
+ INSTR_TIME_SET_CURRENT(io_start);
+ else
+ INSTR_TIME_SET_ZERO(io_start);
+
/* And write... */
smgrwrite(oreln,
BufTagGetForkNum(&bufHdr->tag),
@@ -239,6 +246,13 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
buf_state &= ~BM_DIRTY;
pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+ if (track_io_timing)
+ {
+ INSTR_TIME_SET_CURRENT(io_time);
+ INSTR_TIME_SUBTRACT(io_time, io_start);
+ pgstat_count_io_time(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_WRITE, io_time);
+ }
+
pgstat_count_io_op(IOOBJECT_TEMP_RELATION, IOCONTEXT_NORMAL, IOOP_WRITE);
pgBufferUsage.local_blks_written++;
}
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 352958e1fe..052875d86a 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -1030,6 +1030,30 @@ register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
if (!RegisterSyncRequest(&tag, SYNC_REQUEST, false /* retryOnError */ ))
{
+ instr_time io_start,
+ io_time;
+
+ if (track_io_timing)
+ INSTR_TIME_SET_CURRENT(io_start);
+ else
+ INSTR_TIME_SET_ZERO(io_start);
+
+ ereport(DEBUG1,
+ (errmsg_internal("could not forward fsync request because request queue is full")));
+
+ if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
+ ereport(data_sync_elevel(ERROR),
+ (errcode_for_file_access(),
+ errmsg("could not fsync file \"%s\": %m",
+ FilePathName(seg->mdfd_vfd))));
+
+ if (track_io_timing)
+ {
+ INSTR_TIME_SET_CURRENT(io_time);
+ INSTR_TIME_SUBTRACT(io_time, io_start);
+ pgstat_count_io_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL, IOOP_FSYNC, io_time);
+ }
+
/*
* We have no way of knowing if the current IOContext is
* IOCONTEXT_NORMAL or IOCONTEXT_[BULKREAD, BULKWRITE, VACUUM] at this
@@ -1042,15 +1066,6 @@ register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
* backend fsyncs.
*/
pgstat_count_io_op(IOOBJECT_RELATION, IOCONTEXT_NORMAL, IOOP_FSYNC);
-
- ereport(DEBUG1,
- (errmsg_internal("could not forward fsync request because request queue is full")));
-
- if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
- ereport(data_sync_elevel(ERROR),
- (errcode_for_file_access(),
- errmsg("could not fsync file \"%s\": %m",
- FilePathName(seg->mdfd_vfd))));
}
}
@@ -1399,6 +1414,8 @@ int
mdsyncfiletag(const FileTag *ftag, char *path)
{
SMgrRelation reln = smgropen(ftag->rlocator, InvalidBackendId);
+ instr_time io_start,
+ io_time;
File file;
bool need_to_close;
int result,
@@ -1425,10 +1442,22 @@ mdsyncfiletag(const FileTag *ftag, char *path)
need_to_close = true;
}
+ if (track_io_timing)
+ INSTR_TIME_SET_CURRENT(io_start);
+ else
+ INSTR_TIME_SET_ZERO(io_start);
+
/* Sync the file. */
result = FileSync(file, WAIT_EVENT_DATA_FILE_SYNC);
save_errno = errno;
+ if (track_io_timing)
+ {
+ INSTR_TIME_SET_CURRENT(io_time);
+ INSTR_TIME_SUBTRACT(io_time, io_start);
+ pgstat_count_io_time(IOOBJECT_RELATION, IOCONTEXT_NORMAL, IOOP_FSYNC, io_time);
+ }
+
if (need_to_close)
FileClose(file);
diff --git a/src/backend/utils/activity/pgstat_io.c b/src/backend/utils/activity/pgstat_io.c
index af5d554610..4a151afed6 100644
--- a/src/backend/utils/activity/pgstat_io.c
+++ b/src/backend/utils/activity/pgstat_io.c
@@ -25,36 +25,48 @@ bool have_iostats = false;
/*
* Check that stats have not been counted for any combination of IOObject,
- * IOContext, and IOOp which are not tracked for the passed-in BackendType. The
- * passed-in PgStat_BktypeIO must contain stats from the BackendType specified
- * by the second parameter. Caller is responsible for locking the passed-in
- * PgStat_BktypeIO, if needed.
+ * IOContext, and IOOp which are not tracked for the passed-in BackendType. If
+ * the IOOp is not counted for this combination but IO time is otherwise
+ * tracked for this IOOp, check that IO time has not been counted for this
+ * combination. If stats are tracked for this combination and IO times are
+ * non-zero, counts should be non-zero.
+ *
+ * The passed-in PgStat_BktypeIO must contain stats from the BackendType
+ * specified by the second parameter. Caller is responsible for locking the
+ * passed-in PgStat_BktypeIO, if needed.
*/
bool
pgstat_bktype_io_stats_valid(PgStat_BktypeIO *backend_io,
BackendType bktype)
{
- bool bktype_tracked = pgstat_tracks_io_bktype(bktype);
-
for (int io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
{
for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
{
- /*
- * Don't bother trying to skip to the next loop iteration if
- * pgstat_tracks_io_object() would return false here. We still
- * need to validate that each counter is zero anyway.
- */
for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
{
- /* No stats, so nothing to validate */
- if (backend_io->data[io_object][io_context][io_op] == 0)
+ /* we do track it */
+ if (pgstat_tracks_io_op(bktype, io_object, io_context, io_op))
+ {
+ /* ensure that if IO times are non-zero, counts are > 0 */
+ if (!INSTR_TIME_IS_ZERO(backend_io->times[io_object][io_context][io_op]) &&
+ backend_io->counts[io_object][io_context][io_op] <= 0)
+ return false;
+
continue;
+ }
- /* There are stats and there shouldn't be */
- if (!bktype_tracked ||
- !pgstat_tracks_io_op(bktype, io_object, io_context, io_op))
+ /* we don't track it, and it is not 0 */
+ if (backend_io->counts[io_object][io_context][io_op] != 0)
return false;
+
+ /* we don't track this IOOp, so make sure its IO time is zero */
+ if (pgstat_tracks_io_time(io_op) > -1)
+ {
+ if (!INSTR_TIME_IS_ZERO(backend_io->times[io_object][io_context][io_op]))
+ return false;
+ }
+
}
}
}
@@ -70,7 +82,21 @@ pgstat_count_io_op(IOObject io_object, IOContext io_context, IOOp io_op)
Assert((unsigned int) io_op < IOOP_NUM_TYPES);
Assert(pgstat_tracks_io_op(MyBackendType, io_object, io_context, io_op));
- PendingIOStats.data[io_object][io_context][io_op]++;
+ PendingIOStats.counts[io_object][io_context][io_op]++;
+
+ have_iostats = true;
+}
+
+void
+pgstat_count_io_time(IOObject io_object, IOContext io_context, IOOp io_op, instr_time time)
+{
+ Assert(io_object < IOOBJECT_NUM_TYPES);
+ Assert(io_context < IOCONTEXT_NUM_TYPES);
+ Assert(io_op < IOOP_NUM_TYPES);
+ Assert(pgstat_tracks_io_op(MyBackendType, io_object, io_context, io_op));
+ Assert(pgstat_tracks_io_time(io_op) != -1);
+
+ INSTR_TIME_ADD(PendingIOStats.times[io_object][io_context][io_op], time);
have_iostats = true;
}
@@ -114,8 +140,13 @@ pgstat_flush_io(bool nowait)
for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
{
for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
- bktype_shstats->data[io_object][io_context][io_op] +=
- PendingIOStats.data[io_object][io_context][io_op];
+ {
+ bktype_shstats->counts[io_object][io_context][io_op] +=
+ PendingIOStats.counts[io_object][io_context][io_op];
+
+ INSTR_TIME_ADD(bktype_shstats->times[io_object][io_context][io_op],
+ PendingIOStats.times[io_object][io_context][io_op]);
+ }
}
}
@@ -384,3 +415,30 @@ pgstat_tracks_io_op(BackendType bktype, IOObject io_object,
return true;
}
+
+/*
+ * PgStat_BktypeIO->times contains IO times for IOOps. For simplicity this
+ * array has a spot for every IOOp. pgstat_tracks_io_time() is the source of
+ * truth for which IOOps have corresponding IO times.
+ */
+IOOp
+pgstat_tracks_io_time(IOOp io_op)
+{
+ switch (io_op)
+ {
+ case IOOP_READ:
+ return IOOP_READ;
+ case IOOP_WRITE:
+ return IOOP_WRITE;
+ case IOOP_EXTEND:
+ return IOOP_EXTEND;
+ case IOOP_FSYNC:
+ return IOOP_FSYNC;
+ case IOOP_EVICT:
+ case IOOP_REUSE:
+ return -1;
+ }
+
+ elog(ERROR, "unrecognized IOOp value: %d", io_op);
+ pg_unreachable();
+}
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index b61a12382b..c75e661290 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1255,12 +1255,16 @@ typedef enum io_stat_col
IO_COL_IO_OBJECT,
IO_COL_IO_CONTEXT,
IO_COL_READS,
+ IO_COL_READ_TIME,
IO_COL_WRITES,
+ IO_COL_WRITE_TIME,
IO_COL_EXTENDS,
+ IO_COL_EXTEND_TIME,
IO_COL_CONVERSION,
IO_COL_EVICTIONS,
IO_COL_REUSES,
IO_COL_FSYNCS,
+ IO_COL_FSYNC_TIME,
IO_COL_RESET_TIME,
IO_NUM_COLUMNS,
} io_stat_col;
@@ -1292,6 +1296,21 @@ pgstat_get_io_op_index(IOOp io_op)
pg_unreachable();
}
+/*
+ * Get the number of the column containing IO times for the specified IOOp. If
+ * the specified IOOp is one for which IO time is not tracked, return -1. Note
+ * that this function assumes that IO time for an IOOp is displayed in the view
+ * in the column directly after the IOOp counts.
+ */
+static io_stat_col
+pgstat_get_io_time_index(IOOp io_op)
+{
+ if (pgstat_tracks_io_time(io_op) == -1)
+ return -1;
+
+ return pgstat_get_io_op_index(io_op) + 1;
+}
+
Datum
pg_stat_get_io(PG_FUNCTION_ARGS)
{
@@ -1359,20 +1378,31 @@ pg_stat_get_io(PG_FUNCTION_ARGS)
for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
{
- int col_idx = pgstat_get_io_op_index(io_op);
+ int i = pgstat_get_io_op_index(io_op);
/*
* Some combinations of BackendType and IOOp, of IOContext
* and IOOp, and of IOObject and IOOp are not tracked. Set
* these cells in the view NULL.
*/
- nulls[col_idx] = !pgstat_tracks_io_op(bktype, io_obj, io_context, io_op);
+ if (pgstat_tracks_io_op(bktype, io_obj, io_context, io_op))
+ values[i] = Int64GetDatum(bktype_stats->counts[io_obj][io_context][io_op]);
+ else
+ nulls[i] = true;
+ }
+
+ for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
+ {
+ int i = pgstat_get_io_time_index(io_op);
- if (nulls[col_idx])
+ if (i == -1)
continue;
- values[col_idx] =
- Int64GetDatum(bktype_stats->data[io_obj][io_context][io_op]);
+ if (!nulls[pgstat_get_io_op_index(io_op)])
+ values[i] =
+ Float8GetDatum(INSTR_TIME_GET_MILLISEC(bktype_stats->times[io_obj][io_context][io_op]));
+ else
+ nulls[i] = true;
}
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 505595620e..80c0627209 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5721,9 +5721,9 @@
proname => 'pg_stat_get_io', provolatile => 'v',
prorows => '30', proretset => 't',
proparallel => 'r', prorettype => 'record', proargtypes => '',
- proallargtypes => '{text,text,text,int8,int8,int8,int8,int8,int8,int8,timestamptz}',
- proargmodes => '{o,o,o,o,o,o,o,o,o,o,o}',
- proargnames => '{backend_type,io_object,io_context,reads,writes,extends,op_bytes,evictions,reuses,fsyncs,stats_reset}',
+ proallargtypes => '{text,text,text,int8,float8,int8,float8,int8,float8,int8,int8,int8,int8,float8,timestamptz}',
+ proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+ proargnames => '{backend_type,io_object,io_context,reads,read_time,writes,write_time,extends,extend_time,op_bytes,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_io' },
{ oid => '1136', descr => 'statistics: information about WAL activity',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index f43fac09ed..687aff4859 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -313,7 +313,8 @@ typedef enum IOOp
typedef struct PgStat_BktypeIO
{
- PgStat_Counter data[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
+ PgStat_Counter counts[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
+ instr_time times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
} PgStat_BktypeIO;
typedef struct PgStat_IO
@@ -507,6 +508,7 @@ extern PgStat_CheckpointerStats *pgstat_fetch_stat_checkpointer(void);
extern bool pgstat_bktype_io_stats_valid(PgStat_BktypeIO *context_ops,
BackendType bktype);
extern void pgstat_count_io_op(IOObject io_object, IOContext io_context, IOOp io_op);
+extern void pgstat_count_io_time(IOObject io_object, IOContext io_context, IOOp io_op, instr_time time);
extern PgStat_IO *pgstat_fetch_stat_io(void);
extern const char *pgstat_get_io_context_name(IOContext io_context);
extern const char *pgstat_get_io_object_name(IOObject io_object);
@@ -516,6 +518,7 @@ extern bool pgstat_tracks_io_object(BackendType bktype,
IOObject io_object, IOContext io_context);
extern bool pgstat_tracks_io_op(BackendType bktype, IOObject io_object,
IOContext io_context, IOOp io_op);
+extern IOOp pgstat_tracks_io_time(IOOp io_op);
/*
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index e953d1f515..5434851314 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1880,14 +1880,18 @@ pg_stat_io| SELECT backend_type,
io_object,
io_context,
reads,
+ read_time,
writes,
+ write_time,
extends,
+ extend_time,
op_bytes,
evictions,
reuses,
fsyncs,
+ fsync_time,
stats_reset
- FROM pg_stat_get_io() b(backend_type, io_object, io_context, reads, writes, extends, op_bytes, evictions, reuses, fsyncs, stats_reset);
+ FROM pg_stat_get_io() b(backend_type, io_object, io_context, reads, read_time, writes, write_time, extends, extend_time, op_bytes, evictions, reuses, fsyncs, fsync_time, stats_reset);
pg_stat_progress_analyze| SELECT s.pid,
s.datid,
d.datname,
--
2.37.2
