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Postgresql10 process

2022-06-11 22:55:00 【m0_ thirty-seven million two hundred and ninety-four thousand f】

pg process

postgres: checkpointer process
postgres: writer process
postgres: wal writer process
postgres: autovacuum launcher process
postgres: stats collector process
postgres: bgworker: logical replication launcher
postgres: {user} db 127.0.0.1(pid) idle
postgres: {user} default 127.0.0.1(pid) idle

pg query analysis

main.c main
postmaster.c PostmasterMain
postmaster.c ServerLoop
postmaster.c BackendStartup
postmaster.c BackendRun
postgres.c PostgresMain
postgres.c exec_simple_query
pquery.c PortalRun
pquery.c PortalRunMulti
pquery.c ProcessQuery

ProcessQuery(PlannedStmt *plan,
			 const char *sourceText,
			 ParamListInfo params,
			 QueryEnvironment *queryEnv,
			 DestReceiver *dest,
			 char *completionTag)
{
	QueryDesc  *queryDesc;
	queryDesc = CreateQueryDesc(plan, sourceText,
								GetActiveSnapshot(), InvalidSnapshot,
								dest, params, queryEnv, 0);

	// Generate execution plan 
ExecutorStart(queryDesc, 0);

// Implementation plan 
ExecutorRun(queryDesc, ForwardScanDirection, 0L, true);

/*
 * Build command completion status string, if caller wants one.
 */
if (completionTag)
{
	Oid			lastOid;

	switch (queryDesc->operation)
	{
		case CMD_SELECT:
			snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
					 "SELECT " UINT64_FORMAT,
					 queryDesc->estate->es_processed);
			break;
		case CMD_INSERT:
			if (queryDesc->estate->es_processed == 1)
				lastOid = queryDesc->estate->es_lastoid;
			else
				lastOid = InvalidOid;
			snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
					 "INSERT %u " UINT64_FORMAT,
					 lastOid, queryDesc->estate->es_processed);
			break;
		case CMD_UPDATE:
			snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
					 "UPDATE " UINT64_FORMAT,
					 queryDesc->estate->es_processed);
			break;
		case CMD_DELETE:
			snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
					 "DELETE " UINT64_FORMAT,
					 queryDesc->estate->es_processed);
			break;
		default:
			strcpy(completionTag, "???");
			break;
	}
}

// Release resources 
ExecutorFinish(queryDesc);
ExecutorEnd(queryDesc);

FreeQueryDesc(queryDesc);

}