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Track IO times in pg_stat_io

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a9c70b46db and 8aaa04b32S added counting of IO operations to a new view,
pg_stat_io. Now, add IO timing for reads, writes, extends, and fsyncs to
pg_stat_io as well.

This combines the tracking for pgBufferUsage with the tracking for pg_stat_io
into a new function pgstat_count_io_op_time(). This should make it a bit
easier to avoid the somewhat costly instr_time conversion done for
pgBufferUsage.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_ay5iKmnbXZ3DsauViF3eMxu4m1oNnJXqV_HyqYeg55Ww%40mail.gmail.com
This commit is contained in:
Andres Freund
2023-04-07 16:05:26 -07:00
parent 1c453cfd89
commit ac8d53dae5
11 changed files with 276 additions and 108 deletions
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109
src/backend/utils/activity/pgstat_io.c
View File

@@ -16,44 +16,55 @@
#include "postgres.h"
#include "executor/instrument.h"
#include "storage/bufmgr.h"
#include "utils/pgstat_internal.h"
static PgStat_BktypeIO PendingIOStats;
typedef struct PgStat_PendingIO
{
PgStat_Counter counts[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
instr_time pending_times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
} PgStat_PendingIO;
static PgStat_PendingIO PendingIOStats;
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
* 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)
continue;
/* 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 (backend_io->times[io_object][io_context][io_op] != 0 &&
backend_io->counts[io_object][io_context][io_op] <= 0)
return false;
/* There are stats and there shouldn't be */
if (!bktype_tracked ||
!pgstat_tracks_io_op(bktype, io_object, io_context, io_op))
continue;
}
/* we don't track it, and it is not 0 */
if (backend_io->counts[io_object][io_context][io_op] != 0)
return false;
}
}
@@ -76,11 +87,58 @@ pgstat_count_io_op_n(IOObject io_object, IOContext io_context, IOOp io_op, uint3
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] += cnt;
PendingIOStats.counts[io_object][io_context][io_op] += cnt;
have_iostats = true;
}
instr_time
pgstat_prepare_io_time(void)
{
instr_time io_start;
if (track_io_timing)
INSTR_TIME_SET_CURRENT(io_start);
else
INSTR_TIME_SET_ZERO(io_start);
return io_start;
}
/*
* Like pgstat_count_io_op_n() except it also accumulates time.
*/
void
pgstat_count_io_op_time(IOObject io_obj, IOContext io_context, IOOp io_op,
instr_time start_time, uint32 cnt)
{
if (track_io_timing)
{
instr_time io_time;
INSTR_TIME_SET_CURRENT(io_time);
INSTR_TIME_SUBTRACT(io_time, start_time);
if (io_op == IOOP_WRITE)
{
pgstat_count_buffer_write_time(INSTR_TIME_GET_MICROSEC(io_time));
if (io_obj == IOOBJECT_RELATION)
INSTR_TIME_ADD(pgBufferUsage.blk_write_time, io_time);
}
else if (io_op == IOOP_READ)
{
pgstat_count_buffer_read_time(INSTR_TIME_GET_MICROSEC(io_time));
if (io_obj == IOOBJECT_RELATION)
INSTR_TIME_ADD(pgBufferUsage.blk_read_time, io_time);
}
INSTR_TIME_ADD(PendingIOStats.pending_times[io_obj][io_context][io_op],
io_time);
}
pgstat_count_io_op_n(io_obj, io_context, io_op, cnt);
}
PgStat_IO *
pgstat_fetch_stat_io(void)
{
@@ -120,8 +178,17 @@ 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];
{
instr_time time;
bktype_shstats->counts[io_object][io_context][io_op] +=
PendingIOStats.counts[io_object][io_context][io_op];
time = PendingIOStats.pending_times[io_object][io_context][io_op];
bktype_shstats->times[io_object][io_context][io_op] +=
INSTR_TIME_GET_MICROSEC(time);
}
}
}