"ERROR: cache lookup failed for function %d" while dropping function from another session - Mailing list pgsql-hackers

From Mahendra Singh Thalor
Subject "ERROR: cache lookup failed for function %d" while dropping function from another session
Date
Msg-id CAKYtNAr5JTARW_vk5yLDHBoepRccg-ju=qJAsA1VgMEsx8Chiw@mail.gmail.com
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Responses Re: "ERROR: cache lookup failed for function %d" while dropping function from another session  (Mahendra Singh Thalor <mahi6run@gmail.com>)
List pgsql-hackers
Hi,
I am able to hit "ERROR:  cache lookup failed for function %d" while I am dropping function from another session.

Reproducible steps are as(I tried on current head d8a75b1308b133502ae3):

Step 1) Fire below query from session-1 to create a function:

create function fun1(int) returns record as ' DECLARE retval RECORD; BEGIN SELECT INTO retval 5, 10, 15; RETURN retval;
END;' language plpgsql;

Step 2) Attach PID of session-1 into gdb and set a breakpoint into internal_get_result_type and then press c.

(gdb) b internal_get_result_type Breakpoint 1 at 0x5565dd4f3ce4: file funcapi.c, line 325. (gdb) c
Continuing.

Step 3) Fire below select command from session-1:

SELECT * FROM fun1(1500) AS (a int, b int, c int);

Step 3) Open session-2 and drop the function:

psql (15devel) Type "help" for help. postgres=# drop function fun1; DROP FUNCTION
postgres=#

Step 4) Press 'c' in gdb for 2 times and we will get an error in the 1st session.

(gdb) c Continuing. Breakpoint 1, internal_get_result_type (funcid=16384, call_expr=0x5565de885af0, rsinfo=0x0, resultTypeId=0x7ffc94572608, resultTupleDesc=0x7ffc94572628) at funcapi.c:325 (gdb) c
Continuing.

postgres=# SELECT * FROM fun1(1500) AS (a int, b int, c int);
ERROR: cache lookup failed for function 16384

Call stack of error:
Breakpoint 2, errfinish (filename=0x55e0b8907c6f "funcapi.c", lineno=336, funcname=0x55e0b89083a0 <__func__.23015> "internal_get_result_type") at elog.c:515
515 ErrorData  *edata = &errordata[errordata_stack_depth];
(gdb) bt
#0  errfinish (filename=0x55e0b8907c6f "funcapi.c", lineno=336, funcname=0x55e0b89083a0 <__func__.23015> "internal_get_result_type") at elog.c:515
#1  0x000055e0b86abdaf in internal_get_result_type (funcid=16384, call_expr=0x55e0ba9e2ad0, rsinfo=0x0, resultTypeId=0x7ffcb7ca4918, resultTupleDesc=0x7ffcb7ca4938)
    at funcapi.c:336
#2  0x000055e0b86ab6d0 in get_expr_result_type (expr=0x55e0ba9e2ad0, resultTypeId=0x7ffcb7ca4918, resultTupleDesc=0x7ffcb7ca4938) at funcapi.c:230
#3  0x000055e0b7fef027 in ExecInitFunctionScan (node=0x55e0ba9e3cd0, estate=0x55e0ba9d2fe0, eflags=16) at nodeFunctionscan.c:370
#4  0x000055e0b7fbb408 in ExecInitNode (node=0x55e0ba9e3cd0, estate=0x55e0ba9d2fe0, eflags=16) at execProcnode.c:254
#5  0x000055e0b7faa1d5 in InitPlan (queryDesc=0x55e0ba926f50, eflags=16) at execMain.c:936
#6  0x000055e0b7fa84b6 in standard_ExecutorStart (queryDesc=0x55e0ba926f50, eflags=16) at execMain.c:263
#7  0x000055e0b7fa7fc7 in ExecutorStart (queryDesc=0x55e0ba926f50, eflags=0) at execMain.c:143
#8  0x000055e0b83ba8de in PortalStart (portal=0x55e0ba968870, params=0x0, eflags=0, snapshot=0x0) at pquery.c:512
#9  0x000055e0b83ae112 in exec_simple_query (query_string=0x55e0ba906760 "SELECT * FROM fun1(1500) AS (a int, b int, c int);") at postgres.c:1175
#10 0x000055e0b83b7a86 in PostgresMain (argc=1, argv=0x7ffcb7ca4f70, dbname=0x55e0ba932770 "postgres", username=0x55e0ba932748 "mahendrathalor") at postgres.c:4488
#11 0x000055e0b825161b in BackendRun (port=0x55e0ba929730) at postmaster.c:4519
#12 0x000055e0b8250971 in BackendStartup (port=0x55e0ba929730) at postmaster.c:4241
#13 0x000055e0b8248a1b in ServerLoop () at postmaster.c:1758
#14 0x000055e0b8247c18 in PostmasterMain (argc=3, argv=0x55e0ba8fee70) at postmaster.c:1430
#15 0x000055e0b808dbe9 in main (argc=3, argv=0x55e0ba8fee70) at main.c:199

 cache lookup failed errors are never an expected behavior(Thanks Robert Hass for your opinion) so I think we should fix this error.

I haven't debugged it so I will debug it and will post my findings in the coming days.

--
Thanks and Regards
Mahendra Singh Thalor
EnterpriseDB: http://www.enterprisedb.com

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