On 2023-May-20, Alexander Lakhin wrote:
> Starting from 038f586d5, the following script:
> echo "
> \startpipeline
> \endpipeline
> " >test.sql
> pgbench -n -M prepared -f test.sql
>
> leads to the pgbench's segfault:
Hah, yeah, that's because an empty pipeline never calls the code to
allocate the flag array. Here's the trivial fix.
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"El hombre nunca sabe de lo que es capaz hasta que lo intenta" (C. Dickens)
>From 50685847e057eb8e7509293fdd81247eb49854ef Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvhe...@alvh.no-ip.org>
Date: Mon, 22 May 2023 13:45:47 +0200
Subject: [PATCH] Fix pgbench in prepared mode with empty pipeline
---
src/bin/pgbench/pgbench.c | 44 ++++++++++++--------
src/bin/pgbench/t/001_pgbench_with_server.pl | 2 +
2 files changed, 28 insertions(+), 18 deletions(-)
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7dbb2ed6a77..6caa84282c7 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3049,6 +3049,27 @@ chooseScript(TState *thread)
return i - 1;
}
+/*
+ * Allocate space for 'prepared' flags of a script: we need one boolean
+ * for each command of each script.
+ */
+static void
+allocatePreparedFlags(CState *st)
+{
+ Assert(st->prepared == NULL);
+
+ st->prepared = pg_malloc(sizeof(bool *) * num_scripts);
+ for (int i = 0; i < num_scripts; i++)
+ {
+ ParsedScript *script = &sql_script[i];
+ int numcmds;
+
+ for (numcmds = 0; script->commands[numcmds] != NULL; numcmds++)
+ ;
+ st->prepared[i] = pg_malloc0(sizeof(bool) * numcmds);
+ }
+}
+
/*
* Prepare the SQL command from st->use_file at command_num.
*/
@@ -3061,23 +3082,8 @@ prepareCommand(CState *st, int command_num)
if (command->type != SQL_COMMAND)
return;
- /*
- * If not already done, allocate space for 'prepared' flags: one boolean
- * for each command of each script.
- */
if (!st->prepared)
- {
- st->prepared = pg_malloc(sizeof(bool *) * num_scripts);
- for (int i = 0; i < num_scripts; i++)
- {
- ParsedScript *script = &sql_script[i];
- int numcmds;
-
- for (numcmds = 0; script->commands[numcmds] != NULL; numcmds++)
- ;
- st->prepared[i] = pg_malloc0(sizeof(bool) * numcmds);
- }
- }
+ allocatePreparedFlags(st);
if (!st->prepared[st->use_file][command_num])
{
@@ -3109,13 +3115,15 @@ prepareCommandsInPipeline(CState *st)
Assert(commands[st->command]->type == META_COMMAND &&
commands[st->command]->meta == META_STARTPIPELINE);
+ if (!st->prepared)
+ allocatePreparedFlags(st);
+
/*
* We set the 'prepared' flag on the \startpipeline itself to flag that we
* don't need to do this next time without calling prepareCommand(), even
* though we don't actually prepare this command.
*/
- if (st->prepared &&
- st->prepared[st->use_file][st->command])
+ if (st->prepared[st->use_file][st->command])
return;
for (j = st->command + 1; commands[j] != NULL; j++)
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 363a1ffabd5..f8ca8a922d1 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -790,6 +790,8 @@ $node->pgbench(
'001_pgbench_pipeline_prep' => q{
-- test startpipeline
\startpipeline
+\endpipeline
+\startpipeline
} . "select 1;\n" x 10 . q{
\endpipeline
}
--
2.39.2
