[PATCH] Avoid unnecessary code execution in Instrument.c when TIMING is FALSE

[Hironobu SUZUKI]

Hi,

Even when using EXPLAIN ANALYZE with TIMING=FALSE, the functions 
InstrStopNode(), InstrEndLoop(), and InstrAggNode() in Instrument.c 
still execute code related to the "starttime", "counter", "firsttuple", 
"startup",  and "total" fields within the Instrumentation structure.
These operations are unnecessary when timing is disabled, and since 
these functions are called very frequently, I have created a patch to 
address this.

As far as I can tell, this change has no side effects and clarifies the 
intent of each line, but please let me know if you notice any issues.

Best regards,
H.S.diff --git a/src/backend/executor/instrument.c 
b/src/backend/executor/instrument.c
index 56e635f4700..e4274a28525 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -114,7 +114,8 @@ InstrStopNode(Instrumentation *instr, double nTuples)
        if (!instr->running)
        {
                instr->running = true;
-               instr->firsttuple = INSTR_TIME_GET_DOUBLE(instr->counter);
+               if (instr->need_timer)
+                       instr->firsttuple = 
INSTR_TIME_GET_DOUBLE(instr->counter);
        }
        else
        {
@@ -122,7 +123,7 @@ InstrStopNode(Instrumentation *instr, double nTuples)
                 * In async mode, if the plan node hadn't emitted any tuples 
before,
                 * this might be the first tuple
                 */
-               if (instr->async_mode && save_tuplecount < 1.0)
+               if (instr->need_timer && instr->async_mode && save_tuplecount < 
1.0)
                        instr->firsttuple = 
INSTR_TIME_GET_DOUBLE(instr->counter);
        }
 }
@@ -149,18 +150,24 @@ InstrEndLoop(Instrumentation *instr)
                elog(ERROR, "InstrEndLoop called on running node");
 
        /* Accumulate per-cycle statistics into totals */
-       totaltime = INSTR_TIME_GET_DOUBLE(instr->counter);
+       if (instr->need_timer)
+       {
+               totaltime = INSTR_TIME_GET_DOUBLE(instr->counter);
 
-       instr->startup += instr->firsttuple;
-       instr->total += totaltime;
+               instr->startup += instr->firsttuple;
+               instr->total += totaltime;
+       }
        instr->ntuples += instr->tuplecount;
        instr->nloops += 1;
 
        /* Reset for next cycle (if any) */
        instr->running = false;
-       INSTR_TIME_SET_ZERO(instr->starttime);
-       INSTR_TIME_SET_ZERO(instr->counter);
-       instr->firsttuple = 0;
+       if (instr->need_timer)
+       {
+               INSTR_TIME_SET_ZERO(instr->starttime);
+               INSTR_TIME_SET_ZERO(instr->counter);
+               instr->firsttuple = 0;
+       }
        instr->tuplecount = 0;
 }
 
@@ -171,16 +178,21 @@ InstrAggNode(Instrumentation *dst, Instrumentation *add)
        if (!dst->running && add->running)
        {
                dst->running = true;
-               dst->firsttuple = add->firsttuple;
+               if (dst->need_timer && add->need_timer)
+                       dst->firsttuple = add->firsttuple;
        }
-       else if (dst->running && add->running && dst->firsttuple > 
add->firsttuple)
+       else if (dst->need_timer && add->need_timer && dst->running && 
add->running
+                        && dst->firsttuple > add->firsttuple)
                dst->firsttuple = add->firsttuple;
 
-       INSTR_TIME_ADD(dst->counter, add->counter);
+       if (dst->need_timer && add->need_timer)
+       {
+               INSTR_TIME_ADD(dst->counter, add->counter);
 
+               dst->startup += add->startup;
+               dst->total += add->total;
+       }
        dst->tuplecount += add->tuplecount;
-       dst->startup += add->startup;
-       dst->total += add->total;
        dst->ntuples += add->ntuples;
        dst->ntuples2 += add->ntuples2;
        dst->nloops += add->nloops;