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Speedup and increase usability of set proc title functions

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The setting of the process title could be seen on profiles of very
fast-to-execute queries.  In many locations where we call
set_ps_display() we pass along a string constant, the length of which is
known during compilation.  Here we effectively rename set_ps_display() to
set_ps_display_with_len() and then add a static inline function named
set_ps_display() which calls strlen() on the given string.  This allows
the compiler to optimize away the strlen() call when dealing with
call sites passing a string constant.  We can then also use memcpy()
instead of strlcpy() to copy the string into the destination buffer.
That's significantly faster than strlcpy's byte-at-a-time way of
copying.

Here we also take measures to improve some code which was adjusting the
process title to add a " waiting" suffix to it.  Call sites which require
this can now just call set_ps_display_suffix() to add or adjust the suffix
and call set_ps_display_remove_suffix() to remove it again.

Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/CAApHDvocBvvk-0gWNA2Gohe+sv9fMcv+fK_G+siBKJrgDG4O7g@mail.gmail.com
This commit is contained in:
David Rowley
2023-02-20 16:18:27 +13:00
parent de2aca2885
commit 2cb82e2acf
7 changed files with 200 additions and 96 deletions
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22
src/backend/replication/syncrep.c
View File

@@ -148,8 +148,6 @@ static bool SyncRepQueueIsOrderedByLSN(int mode);
void
SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
{
char *new_status = NULL;
const char *old_status;
int mode;
/*
@@ -216,15 +214,10 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
/* Alter ps display to show waiting for sync rep. */
if (update_process_title)
{
int len;
char buffer[32];
old_status = get_ps_display(&len);
new_status = (char *) palloc(len + 32 + 1);
memcpy(new_status, old_status, len);
sprintf(new_status + len, " waiting for %X/%X",
LSN_FORMAT_ARGS(lsn));
set_ps_display(new_status);
new_status[len] = '\0'; /* truncate off " waiting ..." */
sprintf(buffer, "waiting for %X/%X", LSN_FORMAT_ARGS(lsn));
set_ps_display_suffix(buffer);
}
/*
@@ -322,12 +315,9 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
MyProc->syncRepState = SYNC_REP_NOT_WAITING;
MyProc->waitLSN = 0;
if (new_status)
{
/* Reset ps display */
set_ps_display(new_status);
pfree(new_status);
}
/* reset ps display to remove the suffix */
if (update_process_title)
set_ps_display_remove_suffix();
}
/*