From: David Rowley <drowley@postgresql.org>
Date: Sun, 12 Apr 2026 22:43:19 +0000 (+1200)
Subject: Use stack-allocated StringInfoDatas, where possible
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a63bbc811d41b3567eb37fe2636e660a852dbbf2;p=thirdparty%2Fpostgresql.git

Use stack-allocated StringInfoDatas, where possible

6d0eba662 already did most of the changes, but some new ones snuck in
just prior to that commit, so these got missed.

Having these short-lived StringInfoDatas on the stack rather than having
them get palloc'd by makeStringInfo() is simply for performance as it
saves doing a 2nd palloc.

Since this code is new to v19, it makes sense to improve it now rather
than wait until we branch as having v19 and v20 differ here just makes it
harder to backpatch fixes in this area.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/adt4wpj4FZwR+S7I@ip-10-97-1-34.eu-west-3.compute.internal
---

diff --git a/src/backend/replication/logical/sequencesync.c b/src/backend/replication/logical/sequencesync.c
index a4fb6783ba9..ec7e76abf93 100644
--- a/src/backend/replication/logical/sequencesync.c
+++ b/src/backend/replication/logical/sequencesync.c
@@ -174,45 +174,45 @@ static void
 report_sequence_errors(List *mismatched_seqs_idx, List *insuffperm_seqs_idx,
 					   List *missing_seqs_idx)
 {
-	StringInfo	seqstr;
+	StringInfoData seqstr;
 
 	/* Quick exit if there are no errors to report */
 	if (!mismatched_seqs_idx && !insuffperm_seqs_idx && !missing_seqs_idx)
 		return;
 
-	seqstr = makeStringInfo();
+	initStringInfo(&seqstr);
 
 	if (mismatched_seqs_idx)
 	{
-		get_sequences_string(mismatched_seqs_idx, seqstr);
+		get_sequences_string(mismatched_seqs_idx, &seqstr);
 		ereport(WARNING,
 				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				errmsg_plural("mismatched or renamed sequence on subscriber (%s)",
 							  "mismatched or renamed sequences on subscriber (%s)",
 							  list_length(mismatched_seqs_idx),
-							  seqstr->data));
+							  seqstr.data));
 	}
 
 	if (insuffperm_seqs_idx)
 	{
-		get_sequences_string(insuffperm_seqs_idx, seqstr);
+		get_sequences_string(insuffperm_seqs_idx, &seqstr);
 		ereport(WARNING,
 				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				errmsg_plural("insufficient privileges on sequence (%s)",
 							  "insufficient privileges on sequences (%s)",
 							  list_length(insuffperm_seqs_idx),
-							  seqstr->data));
+							  seqstr.data));
 	}
 
 	if (missing_seqs_idx)
 	{
-		get_sequences_string(missing_seqs_idx, seqstr);
+		get_sequences_string(missing_seqs_idx, &seqstr);
 		ereport(WARNING,
 				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				errmsg_plural("missing sequence on publisher (%s)",
 							  "missing sequences on publisher (%s)",
 							  list_length(missing_seqs_idx),
-							  seqstr->data));
+							  seqstr.data));
 	}
 
 	ereport(ERROR,
@@ -388,10 +388,13 @@ copy_sequences(WalReceiverConn *conn)
 	List	   *mismatched_seqs_idx = NIL;
 	List	   *missing_seqs_idx = NIL;
 	List	   *insuffperm_seqs_idx = NIL;
-	StringInfo	seqstr = makeStringInfo();
-	StringInfo	cmd = makeStringInfo();
+	StringInfoData seqstr;
+	StringInfoData cmd;
 	MemoryContext oldctx;
 
+	initStringInfo(&seqstr);
+	initStringInfo(&cmd);
+
 #define MAX_SEQUENCES_SYNC_PER_BATCH 100
 
 	elog(DEBUG1,
@@ -423,13 +426,13 @@ copy_sequences(WalReceiverConn *conn)
 			LogicalRepSequenceInfo *seqinfo =
 				(LogicalRepSequenceInfo *) list_nth(seqinfos, idx);
 
-			if (seqstr->len > 0)
-				appendStringInfoString(seqstr, ", ");
+			if (seqstr.len > 0)
+				appendStringInfoString(&seqstr, ", ");
 
 			nspname_literal = quote_literal_cstr(seqinfo->nspname);
 			seqname_literal = quote_literal_cstr(seqinfo->seqname);
 
-			appendStringInfo(seqstr, "(%s, %s, %d)",
+			appendStringInfo(&seqstr, "(%s, %s, %d)",
 							 nspname_literal, seqname_literal, idx);
 
 			if (++batch_size == MAX_SEQUENCES_SYNC_PER_BATCH)
@@ -468,7 +471,7 @@ copy_sequences(WalReceiverConn *conn)
 		 * corresponding local entries without relying on result order or name
 		 * matching.
 		 */
-		appendStringInfo(cmd,
+		appendStringInfo(&cmd,
 						 "SELECT s.seqidx, ps.*, seq.seqtypid,\n"
 						 "       seq.seqstart, seq.seqincrement, seq.seqmin,\n"
 						 "       seq.seqmax, seq.seqcycle\n"
@@ -477,9 +480,9 @@ copy_sequences(WalReceiverConn *conn)
 						 "JOIN pg_class c ON c.relnamespace = n.oid AND c.relname = s.seqname\n"
 						 "JOIN pg_sequence seq ON seq.seqrelid = c.oid\n"
 						 "JOIN LATERAL pg_get_sequence_data(seq.seqrelid) AS ps ON true\n",
-						 seqstr->data);
+						 seqstr.data);
 
-		res = walrcv_exec(conn, cmd->data, lengthof(seqRow), seqRow);
+		res = walrcv_exec(conn, cmd.data, lengthof(seqRow), seqRow);
 		if (res->status != WALRCV_OK_TUPLES)
 			ereport(ERROR,
 					errcode(ERRCODE_CONNECTION_FAILURE),
@@ -567,8 +570,8 @@ copy_sequences(WalReceiverConn *conn)
 
 		ExecDropSingleTupleTableSlot(slot);
 		walrcv_clear_result(res);
-		resetStringInfo(seqstr);
-		resetStringInfo(cmd);
+		resetStringInfo(&seqstr);
+		resetStringInfo(&cmd);
 
 		batch_missing_count = batch_size - (batch_succeeded_count +
 											batch_mismatched_count +