Re: Plproxy with returns table() make PG segfault

top post: this looks like a plproxy bug (no ?), I've added Marko in CC.

> I've a segfault on a PostgreSQL 9.1 cluster, with a plproxy function
> call. Both PostgreSQL and plproxy are up to date. I use SQL/MED in that
> specific case, but it's the same without. I reproduced the following
> scenario on a few clusters, with or without streaming replication.
>
> On a given cluster, I created this function (very stupid, I know) (note
> the « returns table () » ) :
>
> p0=# create function testtoto( id int)
> returns table(id int, t text)
> language sql
> as $$
> select * from (values(1, 'test'),(2, 'toto') )as toto;
> $$;
> p0=# \df testtoto
> List of functions
> Schema | Name | Result data type | Argument data types | Type
> --------+----------+---------------------------+---------------------+-----
> --- public | testtoto | TABLE(id integer, t text) | id integer | normal (1
> row)
>
>
> And I use it on another cluster, by doing this :
>
> test=# CREATE SERVER test FOREIGN DATA WRAPPER plproxy
> options( connection_lifetime '200',p0 'host=localhost port=5433
> dbname=p0 user=postgres');
> CREATE USER MAPPING FOR postgres SERVER test OPTIONS (user 'postgres');
>
> -- this function returns setof record
>
> test=# CREATE OR REPLACE FUNCTION test(IN _account_id integer, OUT id
> integer, OUT t text )
> RETURNS setof record
> LANGUAGE plproxy
> AS $function$
> CLUSTER 'test';
> TARGET testtoto;
> $function$;
>
> -- this on returns TABLE()
>
> test=# CREATE OR REPLACE FUNCTION test2(IN _account_id integer)
> returns TABLE( id integer, t text )
> LANGUAGE plproxyAS $function$
> CLUSTER 'test';
> TARGET testtoto;
> $function$;
>
> When I call test(), everything is OK :
>
> test=# select * from test(1);
> id | t
> ----+------
> 1 | test
> 2 | toto
> (2 rows)
>
> But when I call test2(1) :
>
> test=# select pg_backend_pid();
> pg_backend_pid
> ----------------
> 25330
> (1 row)
> test=# select * from test2(1);
> The connection to the server was lost. Attempting reset: Failed.
> !>
>
> Badaboum !
>
> And the log reads :
>
> 2012-11-15 18:07:55 CET LOG: server process (PID 25330) was terminated
> by signal 11: Segmentation fault
> 2012-11-15 18:07:55 CET LOG: terminating any other active server processes
> 2012-11-15 18:07:55 CET WARNING: terminating connection because of crash
> of another server process
> 2012-11-15 18:07:55 CET DETAIL: The postmaster has commanded this server
> process to roll back the current transaction and exit, because another
> server process exited abnormally and possibly corrupted shared memory.
> 2012-11-15 18:07:55 CET HINT: In a moment you should be able to
> reconnect to the database and repeat your command.
>
> …
>
> When I try to debug the session, I get this trace :
>
> (gdb)
> Run till exit from #0 PostgresMain (argc=<optimized out>,
> argv=<optimized out>, username=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/tcop/postgres.c:3932
>
> Program received signal SIGSEGV, Segmentation fault.
> pg_detoast_datum_packed (datum=0x800000000) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/utils/fmgr/fmgr.c:2272
> 2272 if (VARATT_IS_COMPRESSED(datum) || VARATT_IS_EXTERNAL(datum))
> (gdb) bt
> #0 pg_detoast_datum_packed (datum=0x800000000) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/utils/fmgr/fmgr.c:2272
> #1 0x00007f26ea7c0040 in text_to_cstring (t=0x800000000) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/utils/adt/varlena.c:135
> #2 0x00007f26ea80a8c6 in FunctionCall1Coll (flinfo=0x7f26eb7fa2b8,
> collation=0, arg1=34359738368) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/utils/fmgr/fmgr.c:1300
> #3 0x00007f26ea80ba2d in OutputFunctionCall (flinfo=0x7f26eb7fa2b8,
> val=34359738368) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/utils/fmgr/fmgr.c:1953
> #4 0x00007f26611c2577 in plproxy_send_type () from
> /usr/lib/postgresql/9.1/lib/plproxy.so
> #5 0x00007f26611bfe66 in plproxy_exec () from
> /usr/lib/postgresql/9.1/lib/plproxy.so
> #6 0x00007f26611c1634 in ?? () from /usr/lib/postgresql/9.1/lib/plproxy.so
> #7 0x00007f26611c1865 in plproxy_call_handler () from
> /usr/lib/postgresql/9.1/lib/plproxy.so
> #8 0x00007f26ea677985 in ExecMakeTableFunctionResult
> (funcexpr=0x7f26eb7e9020, econtext=0x7f26eb7e7ff0,
> expectedDesc=<optimized out>, randomAccess=<optimized out>)
> at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execQual.c:2146
> #9 0x00007f26ea688471 in FunctionNext (node=0x7f26eb7e7ee0) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/nodeFunctionsca
> n.c:66 #10 0x00007f26ea678657 in ExecScanFetch (recheckMtd=<optimized out>,
> accessMtd=<optimized out>, node=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execScan.c:82
> #11 ExecScan (node=0x7f26eb7e7ee0, accessMtd=<optimized out>,
> recheckMtd=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execScan.c:132
> #12 0x00007f26ea670da8 in ExecProcNode (node=0x7f26eb7e7ee0) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execProcnode.c:
> 416 #13 0x00007f26ea66fbf2 in ExecutePlan (dest=<optimized out>,
> direction=<optimized out>, numberTuples=<optimized out>,
> sendTuples=<optimized out>, operation=<optimized out>,
> planstate=<optimized out>, estate=<optimized out>)
> at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execMain.c:1440
> #14 standard_ExecutorRun (queryDesc=0x7f26eb7a1790,
> direction=NoMovementScanDirection, count=0) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/executor/execMain.c:314
> #15 0x00007f26ea7461d7 in PortalRunSelect (portal=0x7f26eb7dbd90,
> forward=<optimized out>, count=0, dest=0x7f26eb6d87a0) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/tcop/pquery.c:943
> #16 0x00007f26ea747640 in PortalRun (portal=<optimized out>,
> count=<optimized out>, isTopLevel=<optimized out>, dest=<optimized out>,
> altdest=<optimized out>, completionTag=<optimized out>)
> at /opt/src/postgresql-9.1-9.1.6/build/../src/backend/tcop/pquery.c:787
> #17 0x00007f26ea7438a3 in exec_simple_query (query_string=<optimized
> out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/tcop/postgres.c:1020
> #18 0x00007f26ea744965 in PostgresMain (argc=<optimized out>,
> argv=<optimized out>, username=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/tcop/postgres.c:3968
> #19 0x00007f26ea702da3 in BackendRun (port=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/postmaster/postmaster.c:
> 3617 #20 BackendStartup (port=<optimized out>) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/postmaster/postmaster.c:
> 3302 #21 ServerLoop () at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/postmaster/postmaster.c:
> 1466 #22 0x00007f26ea705861 in PostmasterMain (argc=-345045536,
> argv=0x7f26eb6cb200) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/postmaster/postmaster.c:
> 1127 #23 0x00007f26ea6a3dc3 in main (argc=5, argv=0x7f26eb6cb1e0) at
> /opt/src/postgresql-9.1-9.1.6/build/../src/backend/main/main.c:199
> (gdb) quit
>
>
> We can see here that "return setof record" works fine, but "return
> table()" crashes.
>
> Even if we can use the first syntax, I don't think we can accept that.

--
Cédric Villemain +33 (0)6 20 30 22 52
http://2ndQuadrant.fr/
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