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neon/compute/patches/pgaudit-parallel_workers-v17.patch
Tristan Partin 8b4fbefc29 Patch pgaudit to disable logging in parallel workers (#12325)
We want to turn logging in parallel workers off to reduce log
amplification in queries which use parallel workers.

Part-of: https://github.com/neondatabase/cloud/issues/28483

Signed-off-by: Tristan Partin <tristan.partin@databricks.com>
2025-07-02 19:54:47 +00:00

144 lines
5.1 KiB
Diff

commit 8d02e4c6c5e1e8676251b0717a46054267091cb4
Author: Tristan Partin <tristan.partin@databricks.com>
Date: 2025-06-23 02:09:31 +0000
Disable logging in parallel workers
When a query uses parallel workers, pgaudit will log the same query for
every parallel worker. This is undesireable since it can result in log
amplification for queries that use parallel workers.
Signed-off-by: Tristan Partin <tristan.partin@databricks.com>
diff --git a/expected/pgaudit.out b/expected/pgaudit.out
index d696287..4b1059a 100644
--- a/expected/pgaudit.out
+++ b/expected/pgaudit.out
@@ -2568,6 +2568,37 @@ DROP SERVER fdw_server;
NOTICE: AUDIT: SESSION,11,1,DDL,DROP SERVER,,,DROP SERVER fdw_server,<not logged>
DROP EXTENSION postgres_fdw;
NOTICE: AUDIT: SESSION,12,1,DDL,DROP EXTENSION,,,DROP EXTENSION postgres_fdw,<not logged>
+--
+-- Test logging in parallel workers
+SET pgaudit.log = 'read';
+SET pgaudit.log_client = on;
+SET pgaudit.log_level = 'notice';
+-- Force parallel execution for testing
+SET max_parallel_workers_per_gather = 2;
+SET parallel_tuple_cost = 0;
+SET parallel_setup_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET min_parallel_index_scan_size = 0;
+-- Create table with enough data to trigger parallel execution
+CREATE TABLE parallel_test (id int, data text);
+INSERT INTO parallel_test SELECT generate_series(1, 1000), 'test data';
+SELECT count(*) FROM parallel_test;
+NOTICE: AUDIT: SESSION,13,1,READ,SELECT,,,SELECT count(*) FROM parallel_test,<not logged>
+ count
+-------
+ 1000
+(1 row)
+
+-- Cleanup parallel test
+DROP TABLE parallel_test;
+RESET max_parallel_workers_per_gather;
+RESET parallel_tuple_cost;
+RESET parallel_setup_cost;
+RESET min_parallel_table_scan_size;
+RESET min_parallel_index_scan_size;
+RESET pgaudit.log;
+RESET pgaudit.log_client;
+RESET pgaudit.log_level;
-- Cleanup
-- Set client_min_messages up to warning to avoid noise
SET client_min_messages = 'warning';
diff --git a/pgaudit.c b/pgaudit.c
index 1764af1..0e48875 100644
--- a/pgaudit.c
+++ b/pgaudit.c
@@ -11,6 +11,7 @@
#include "postgres.h"
#include "access/htup_details.h"
+#include "access/parallel.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "access/relation.h"
@@ -1406,7 +1407,7 @@ pgaudit_ExecutorStart_hook(QueryDesc *queryDesc, int eflags)
{
AuditEventStackItem *stackItem = NULL;
- if (!internalStatement)
+ if (!internalStatement && !IsParallelWorker())
{
/* Push the audit event onto the stack */
stackItem = stack_push();
@@ -1489,7 +1490,7 @@ pgaudit_ExecutorCheckPerms_hook(List *rangeTabls, List *permInfos, bool abort)
/* Log DML if the audit role is valid or session logging is enabled */
if ((auditOid != InvalidOid || auditLogBitmap != 0) &&
- !IsAbortedTransactionBlockState())
+ !IsAbortedTransactionBlockState() && !IsParallelWorker())
{
/* If auditLogRows is on, wait for rows processed to be set */
if (auditLogRows && auditEventStack != NULL)
@@ -1544,7 +1545,7 @@ pgaudit_ExecutorRun_hook(QueryDesc *queryDesc, ScanDirection direction, uint64 c
else
standard_ExecutorRun(queryDesc, direction, count, execute_once);
- if (auditLogRows && !internalStatement)
+ if (auditLogRows && !internalStatement && !IsParallelWorker())
{
/* Find an item from the stack by the query memory context */
stackItem = stack_find_context(queryDesc->estate->es_query_cxt);
@@ -1564,7 +1565,7 @@ pgaudit_ExecutorEnd_hook(QueryDesc *queryDesc)
AuditEventStackItem *stackItem = NULL;
AuditEventStackItem *auditEventStackFull = NULL;
- if (auditLogRows && !internalStatement)
+ if (auditLogRows && !internalStatement && !IsParallelWorker())
{
/* Find an item from the stack by the query memory context */
stackItem = stack_find_context(queryDesc->estate->es_query_cxt);
diff --git a/sql/pgaudit.sql b/sql/pgaudit.sql
index e161f01..c873098 100644
--- a/sql/pgaudit.sql
+++ b/sql/pgaudit.sql
@@ -1637,6 +1637,36 @@ DROP USER MAPPING FOR regress_user1 SERVER fdw_server;
DROP SERVER fdw_server;
DROP EXTENSION postgres_fdw;
+--
+-- Test logging in parallel workers
+SET pgaudit.log = 'read';
+SET pgaudit.log_client = on;
+SET pgaudit.log_level = 'notice';
+
+-- Force parallel execution for testing
+SET max_parallel_workers_per_gather = 2;
+SET parallel_tuple_cost = 0;
+SET parallel_setup_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET min_parallel_index_scan_size = 0;
+
+-- Create table with enough data to trigger parallel execution
+CREATE TABLE parallel_test (id int, data text);
+INSERT INTO parallel_test SELECT generate_series(1, 1000), 'test data';
+
+SELECT count(*) FROM parallel_test;
+
+-- Cleanup parallel test
+DROP TABLE parallel_test;
+RESET max_parallel_workers_per_gather;
+RESET parallel_tuple_cost;
+RESET parallel_setup_cost;
+RESET min_parallel_table_scan_size;
+RESET min_parallel_index_scan_size;
+RESET pgaudit.log;
+RESET pgaudit.log_client;
+RESET pgaudit.log_level;
+
-- Cleanup
-- Set client_min_messages up to warning to avoid noise
SET client_min_messages = 'warning';