diff options
| author | Robert Haas <rhaas@postgresql.org> | 2012-02-07 11:23:04 -0500 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2012-02-07 11:23:04 -0500 |
| commit | af7914c6627bcf0b0ca614e9ce95d3f8056602bf (patch) | |
| tree | 23633b1c4de9e6bbbc9cea30895f8b4ee74e4c01 /src/backend/executor/instrument.c | |
| parent | 1631598ea204a3b05104f25d008b510ff5a5c94a (diff) | |
Add TIMING option to EXPLAIN, to allow eliminating of timing overhead.
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.
Diffstat (limited to 'src/backend/executor/instrument.c')
| -rw-r--r-- | src/backend/executor/instrument.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c index dde73b79192..2c749b13cd8 100644 --- a/src/backend/executor/instrument.c +++ b/src/backend/executor/instrument.c @@ -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"); @@ -68,16 +70,22 @@ 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; - } - INSTR_TIME_SET_CURRENT(endtime); - INSTR_TIME_ACCUM_DIFF(instr->counter, endtime, instr->starttime); + if (INSTR_TIME_IS_ZERO(instr->starttime)) + { + elog(DEBUG2, "InstrStopNode called without start"); + return; + } - 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) |