PG17 - SQLSmith - Server Crash Due to MERGE Command on Distributed Table with Schema-Based Sharding

[m3hm3t]

Executing a MERGE command on a distributed table (dist_sc_1.schema_based_sharding_1) caused the PostgreSQL server to crash with signal 6: Aborted, forcing the termination of active server processes.

Steps to Reproduce

CREATE TABLE dist_sc_1.schema_based_sharding_1 (
    id INTEGER
);

-- Distributed table configuration
SELECT create_distributed_table('dist_sc_1.schema_based_sharding_1', 'id');

MERGE INTO dist_sc_1.schema_based_sharding_1 AS target_0
USING pg_catalog.pg_class AS ref_0
  INNER JOIN information_schema.check_constraints AS ref_1
  ON (
    CASE 
      WHEN 
        CASE 
          WHEN (ref_0.reltuples = (SELECT null_frac FROM pg_catalog.pg_stats LIMIT 1 OFFSET 4)) 
          OR (CAST(NULL AS xid8) >= CAST(NULL AS xid8)) 
          THEN CAST(NULL AS lseg) 
          ELSE CAST(NULL AS lseg) 
        END > CAST(NULL AS lseg) 
      THEN CAST(NULL AS jsonb) 
      ELSE CAST(NULL AS jsonb) 
    END 
    <= 
    CASE 
      WHEN FALSE OR FALSE 
      THEN CAST(NULL AS jsonb) 
      ELSE CAST(NULL AS jsonb) 
    END
  )
ON target_0.id = ref_0.relpages 
WHEN NOT MATCHED
  AND CAST(NULL AS circle) <@ CAST(NULL AS circle)
THEN DO NOTHING;

Schema Details

\d+ dist_sc_1.schema_based_sharding_1
                                Table "dist_sc_1.schema_based_sharding_1"
┌────────┬─────────┬───────────┬──────────┬─────────┬─────────┬─────────────┬──────────────┬─────────────┐
│ Column │  Type   │ Collation │ Nullable │ Default │ Storage │ Compression │ Stats target │ Description │
├────────┼─────────┼───────────┼──────────┼─────────┼─────────┼─────────────┼──────────────┼─────────────┤
│ id     │ integer │           │          │         │ plain   │             │              │             │
└────────┴─────────┴───────────┴──────────┴─────────┴─────────┴─────────────┴──────────────┴─────────────┘
Access method: heap

Crash Logs

2025-01-10 22:02:11.451 UTC [11846] LOG:  server process (PID 59459) was terminated by signal 6: Aborted
2025-01-10 22:02:11.451 UTC [11846] DETAIL:  Failed process was running: MERGE INTO dist_sc_1.schema_based_sharding_1 as target_0
        USING pg_catalog.pg_class as ref_0
          inner join information_schema.check_constraints as ref_1
          on (case when case when (ref_0.reltuples = (select null_frac from pg_catalog.pg_stats limit 1 offset 4)
                          ) 
                      or (cast(null as xid8) >= cast(null as xid8)) then cast(null as lseg) else cast(null as lseg) end
                     > cast(null as lseg) then cast(null as jsonb) else cast(null as jsonb) end
                 <= case when (false) 
                  or (false) then cast(null as jsonb) else cast(null as jsonb) end
                )
        ON target_0.id = ref_0.relpages 
        WHEN NOT MATCHED
          AND cast(null as circle) <@ cast(null as circle)
           THEN DO NOTHING

2025-01-10 22:02:11.451 UTC [11846] LOG:  terminating any other active server processes