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Postgres_fdw join pushdown - getting server crash in left outer join of three table - Mailing list pgsql-hackers

From Rajkumar Raghuwanshi
Subject Postgres_fdw join pushdown - getting server crash in left outer join of three table
Date
Msg-id CAKcux6=uEP9Op+8N6XHQ8kV4YzUi-E1RBWE8L+3oUeyYAhJ1fw@mail.gmail.com
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Responses Re: Postgres_fdw join pushdown - getting server crash in left outer join of three table
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Hi,

I am testing postgres_fdw join pushdown feature for PostgreSQL 9.6 DB, and I observed below issue.

Observation: If do a left outer join on foreign tables more than two times. It is causing the server crash.

Added below statement in contrib/postgres_fdw/postgres_fdw.sql and ran make check, did a server crash

-- left outer join three tables
EXPLAIN (COSTS false, VERBOSE)
SELECT t1.c1,t2.c1,t3.c1 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) LEFT JOIN ft2 t3 ON (t2.c1 = t3.c1) OFFSET 10 LIMIT 10;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
connection to server was lost

Facing the same crash while doing left outer join, right outer join or combination of left-right outer joins for three tables and one local and two foreign tables.

Thanks & Regards,
Rajkumar Raghuwanshi
QMG, EnterpriseDB Corporation

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