Thread

BUG #19105: Parallel Hash Join crash when work_mem is small

PG Bug reporting form <noreply@postgresql.org> — 2025-11-08T22:01:45Z

The following bug has been logged on the website:

Bug reference:      19105
Logged by:          Nagesh Ka
Email address:      nageshdbaa@gmail.com
PostgreSQL version: 16.2
Operating system:   Ubuntu 22.04 x86_64
Description:        

PostgreSQL version: 16.2 (Ubuntu 22.04 x86_64)
Compiled by gcc (Ubuntu 11.4.0)
work_mem = 1MB
max_parallel_workers_per_gather = 4

CREATE TABLE t1 AS SELECT i, md5(i::text) AS txt FROM
generate_series(1,1000000) i;
CREATE TABLE t2 AS SELECT i, md5(i::text) AS txt FROM
generate_series(1,1000000) i;

SET work_mem = '1MB';
SET max_parallel_workers_per_gather = 4;

SELECT t1.i, count(*)
FROM t1 JOIN t2 USING(i)
GROUP BY t1.i;

-->Expected Result

Query should complete successfully and return a count for each key.

-->Observed Result

Server terminates with:

ERROR:  could not attach to dynamic shared area
DETAIL:  invalid dsa_handle