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 a4fb6783ba958b78eab89b4073068808b2110e5a..ec7e76abf934fb0e1b5b61231dca5980ab38a45b 100644 (file)
--- 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 +