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

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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.

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
2020-04-03 11:27:09 +09:00
parent ac44367efb
commit ed7a509571
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);