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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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32
src/backend/tcop/dest.c
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@@ -100,7 +100,7 @@ DestReceiver *None_Receiver = (DestReceiver *) &donothingDR;
* ----------------
*/
void
BeginCommand(const char *commandTag, CommandDest dest)
BeginCommand(CommandTag commandTag, CommandDest dest)
{
/* Nothing to do at present */
}
@@ -163,8 +163,12 @@ CreateDestReceiver(CommandDest dest)
* ----------------
*/
void
EndCommand(const char *commandTag, CommandDest dest)
EndCommand(const QueryCompletion *qc, CommandDest dest, bool force_undecorated_output)
{
char completionTag[COMPLETION_TAG_BUFSIZE];
CommandTag tag;
const char *tagname;
switch (dest)
{
case DestRemote:
@@ -172,11 +176,27 @@ EndCommand(const char *commandTag, CommandDest dest)
case DestRemoteSimple:
/*
* We assume the commandTag is plain ASCII and therefore requires
* no encoding conversion.
* We assume the tagname is plain ASCII and therefore requires no
* encoding conversion.
*
* We no longer display LastOid, but to preserve the wire
* protocol, we write InvalidOid where the LastOid used to be
* written.
*
* All cases where LastOid was written also write nprocessed
* count, so just Assert that rather than having an extra test.
*/
pq_putmessage('C', commandTag, strlen(commandTag) + 1);
break;
tag = qc->commandTag;
tagname = GetCommandTagName(tag);
if (command_tag_display_rowcount(tag) && !force_undecorated_output)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
tag == CMDTAG_INSERT ?
"%s 0 " UINT64_FORMAT : "%s " UINT64_FORMAT,
tagname, qc->nprocessed);
else
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s", tagname);
pq_putmessage('C', completionTag, strlen(completionTag) + 1);
case DestNone:
case DestDebug: