Speedup and increase usability of set proc title functions

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

1 files changed, 9 insertions, 2 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 5d439f27100..cab709b07b1 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -1071,6 +1071,8 @@ exec_simple_query(const char *query_string)
 		Portal		portal;
 		DestReceiver *receiver;
 		int16		format;
+		const char *cmdtagname;
+		size_t		cmdtaglen;
 
 		pgstat_report_query_id(0, true);
 
@@ -1081,8 +1083,9 @@ exec_simple_query(const char *query_string)
 		 * destination.
 		 */
 		commandTag = CreateCommandTag(parsetree->stmt);
+		cmdtagname = GetCommandTagNameAndLen(commandTag, &cmdtaglen);
 
-		set_ps_display(GetCommandTagName(commandTag));
+		set_ps_display_with_len(cmdtagname, cmdtaglen);
 
 		BeginCommand(commandTag, dest);
 
@@ -2064,6 +2067,8 @@ exec_execute_message(const char *portal_name, long max_rows)
 	char		msec_str[32];
 	ParamsErrorCbData params_data;
 	ErrorContextCallback params_errcxt;
+	const char *cmdtagname;
+	size_t		cmdtaglen;
 
 	/* Adjust destination to tell printtup.c what to do */
 	dest = whereToSendOutput;
@@ -2110,7 +2115,9 @@ exec_execute_message(const char *portal_name, long max_rows)
 
 	pgstat_report_activity(STATE_RUNNING, sourceText);
 
-	set_ps_display(GetCommandTagName(portal->commandTag));
+	cmdtagname = GetCommandTagNameAndLen(portal->commandTag, &cmdtaglen);
+
+	set_ps_display_with_len(cmdtagname, cmdtaglen);
 
 	if (save_log_statement_stats)
 		ResetUsage();