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Include information on buffer usage during planning phase, in EXPLAIN output, take two.

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When BUFFERS option is enabled, EXPLAIN command includes the information
on buffer usage during each plan node, in its output. In addition to that,
this commit makes EXPLAIN command include also the information on
buffer usage during planning phase, in its output. This feature makes it
easier to discern the cases where lots of buffer access happen during
planning.

This commit revives the original commit ed7a509571 that was reverted by
commit 19db23bcbd. The original commit had to be reverted because
it caused the regression test failure on the buildfarm members prion and
dory. But since commit c0885c4c30 got rid of the caues of the test failure,
the original commit can be safely introduced again.

Author: Julien Rouhaud, slightly revised by Fujii Masao
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/16109-26a1a88651e90608@postgresql.org
This commit is contained in:
Fujii Masao
2020-04-04 03:13:17 +09:00
parent e41955faf0
commit ce77abe63c
4 changed files with 95 additions and 8 deletions
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13
src/backend/commands/prepare.c
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@@ -616,7 +616,11 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
EState *estate = NULL;
instr_time planstart;
instr_time planduration;
BufferUsage bufusage_start,
bufusage;
if (es->buffers)
bufusage_start = pgBufferUsage;
INSTR_TIME_SET_CURRENT(planstart);
/* Look it up in the hash table */
@@ -654,6 +658,13 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
INSTR_TIME_SET_CURRENT(planduration);
INSTR_TIME_SUBTRACT(planduration, planstart);
/* calc differences of buffer counters. */
if (es->buffers)
{
memset(&bufusage, 0, sizeof(BufferUsage));
BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
}
plan_list = cplan->stmt_list;
/* Explain each query */
@@ -663,7 +674,7 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
if (pstmt->commandType != CMD_UTILITY)
ExplainOnePlan(pstmt, into, es, query_string, paramLI, queryEnv,
&planduration);
&planduration, (es->buffers ? &bufusage : NULL));
else
ExplainOneUtility(pstmt->utilityStmt, into, es, query_string,
paramLI, queryEnv);