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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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16
src/backend/commands/portalcmds.c
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@ -106,7 +106,7 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, ParamListInfo pa
PortalDefineQuery(portal,
NULL,
queryString,
"SELECT", /* cursor's query is always a SELECT */
CMDTAG_SELECT, /* cursor's query is always a SELECT */
list_make1(plan),
NULL);
@ -160,15 +160,14 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, ParamListInfo pa
*
* stmt: parsetree node for command
* dest: where to send results
* completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
* in which to store a command completion status string.
* qc: where to store a command completion status data.
*
* completionTag may be NULL if caller doesn't want a status string.
* qc may be NULL if caller doesn't want status data.
*/
void
PerformPortalFetch(FetchStmt *stmt,
DestReceiver *dest,
char *completionTag)
QueryCompletion *qc)
{
Portal portal;
uint64 nprocessed;
@ -203,10 +202,9 @@ PerformPortalFetch(FetchStmt *stmt,
dest);
/* Return command status if wanted */
if (completionTag)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s " UINT64_FORMAT,
stmt->ismove ? "MOVE" : "FETCH",
nprocessed);
if (qc)
SetQueryCompletion(qc, stmt->ismove ? CMDTAG_MOVE : CMDTAG_FETCH,
nprocessed);
}
/*