database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Add TIMING option to EXPLAIN, to allow eliminating of timing overhead.

Browse Source 
Sometimes it may be useful to get actual row counts out of EXPLAIN
(ANALYZE) without paying the cost of timing every node entry/exit.
With this patch, you can say EXPLAIN (ANALYZE, TIMING OFF) to get that.

Tomas Vondra, reviewed by Eric Theise, with minor doc changes by me.
This commit is contained in:
Robert Haas
2012-02-07 11:23:04 -05:00
parent 1631598ea2
commit af7914c662
6 changed files with 98 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/backend/executor/instrument.c
View File

@ -29,17 +29,19 @@ InstrAlloc(int n, int instrument_options)
{
Instrumentation *instr;
/* timer is always required for now */
Assert(instrument_options & INSTRUMENT_TIMER);
/* initialize all fields to zeroes, then modify as needed */
instr = palloc0(n * sizeof(Instrumentation));
if (instrument_options & INSTRUMENT_BUFFERS)
if (instrument_options & (INSTRUMENT_BUFFERS | INSTRUMENT_TIMER))
{
int i;
bool need_buffers = instrument_options & INSTRUMENT_BUFFERS;
bool need_timer = instrument_options & INSTRUMENT_TIMER;
for (i = 0; i < n; i++)
instr[i].need_bufusage = true;
{
instr[i].need_bufusage = need_buffers;
instr[i].need_timer = need_timer;
}
}
return instr;
@ -49,7 +51,7 @@ InstrAlloc(int n, int instrument_options)
void
InstrStartNode(Instrumentation *instr)
{
if (INSTR_TIME_IS_ZERO(instr->starttime))
if (instr->need_timer && INSTR_TIME_IS_ZERO(instr->starttime))
INSTR_TIME_SET_CURRENT(instr->starttime);
else
elog(DEBUG2, "InstrStartNode called twice in a row");
@ -68,17 +70,23 @@ InstrStopNode(Instrumentation *instr, double nTuples)
/* count the returned tuples */
instr->tuplecount += nTuples;
if (INSTR_TIME_IS_ZERO(instr->starttime))
/* let's update the time only if the timer was requested */
if (instr->need_timer)
{
elog(DEBUG2, "InstrStopNode called without start");
return;
if (INSTR_TIME_IS_ZERO(instr->starttime))
{
elog(DEBUG2, "InstrStopNode called without start");
return;
}
INSTR_TIME_SET_CURRENT(endtime);
INSTR_TIME_ACCUM_DIFF(instr->counter, endtime, instr->starttime);
INSTR_TIME_SET_ZERO(instr->starttime);
}
INSTR_TIME_SET_CURRENT(endtime);
INSTR_TIME_ACCUM_DIFF(instr->counter, endtime, instr->starttime);
INSTR_TIME_SET_ZERO(instr->starttime);
/* Add delta of buffer usage since entry to node's totals */
if (instr->need_bufusage)
BufferUsageAccumDiff(&instr->bufusage,