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Represent command completion tags as structs

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The backend was using strings to represent command tags and doing string
comparisons in multiple places, but that's slow and unhelpful.  Create a
new command list with a supporting structure to use instead; this is
stored in a tag-list-file that can be tailored to specific purposes with
a caller-definable C macro, similar to what we do for WAL resource
managers.  The first first such uses are a new CommandTag enum and a
CommandTagBehavior struct.

Replace numerous occurrences of char *completionTag with a
QueryCompletion struct so that the code no longer stores information
about completed queries in a cstring.  Only at the last moment, in
EndCommand(), does this get converted to a string.

EventTriggerCacheItem no longer holds an array of palloc’d tag strings
in sorted order, but rather just a Bitmapset over the CommandTags.

Author: Mark Dilger, with unsolicited help from Álvaro Herrera
Reviewed-by: John Naylor, Tom Lane
Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com
This commit is contained in:
Alvaro Herrera
2020-03-02 18:19:51 -03:00
parent 7b425a5283
commit 2f9661311b
39 changed files with 877 additions and 621 deletions
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14
src/backend/commands/createas.c
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@ -10,7 +10,7 @@
*
* Formerly, CTAS was implemented as a variant of SELECT, which led
* to assorted legacy behaviors that we still try to preserve, notably that
* we must return a tuples-processed count in the completionTag. (We no
* we must return a tuples-processed count in the QueryCompletion. (We no
* longer do that for CTAS ... WITH NO DATA, however.)
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
@ -225,7 +225,7 @@ create_ctas_nodata(List *tlist, IntoClause *into)
ObjectAddress
ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
ParamListInfo params, QueryEnvironment *queryEnv,
char *completionTag)
QueryCompletion *qc)
{
Query *query = castNode(Query, stmt->query);
IntoClause *into = stmt->into;
@ -270,7 +270,7 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
ExecuteStmt *estmt = castNode(ExecuteStmt, query->utilityStmt);
Assert(!is_matview); /* excluded by syntax */
ExecuteQuery(pstate, estmt, into, params, dest, completionTag);
ExecuteQuery(pstate, estmt, into, params, dest, qc);
/* get object address that intorel_startup saved for us */
address = ((DR_intorel *) dest)->reladdr;
@ -352,11 +352,9 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
/* run the plan to completion */
ExecutorRun(queryDesc, ForwardScanDirection, 0L, true);
/* save the rowcount if we're given a completionTag to fill */
if (completionTag)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
"SELECT " UINT64_FORMAT,
queryDesc->estate->es_processed);
/* save the rowcount if we're given a qc to fill */
if (qc)
SetQueryCompletion(qc, CMDTAG_SELECT, queryDesc->estate->es_processed);
/* get object address that intorel_startup saved for us */
address = ((DR_intorel *) dest)->reladdr;