#99 Server crash in case of WHERE CURRENT OF

[沈 长海]

steps:
1.create table:
CREATE TABLE uctest(f1 int, f2 text);
2.insert data
INSERT INTO uctest VALUES (1, 'one');
INSERT INTO uctest VALUES (2, 'two');
INSERT INTO uctest VALUES (3, 'three');
3.cursor:
BEGIN;
DECLARE c1 CURSOR FOR SELECT * FROM uctest ORDER BY f1;
FETCH 2 FROM c1;
DELETE FROM uctest WHERE CURRENT OF c1;
4.executed results:
server closed
5.core log:
Core was generated by `postgres: shench postgres [local] DELETE '.
Program terminated with signal 11, Segmentation fault.
[New process 23656]
#0 0x000000000056155f in pgxc_node_send_gxid (handle=0xaebed00, gxid=1749) at pgxcnode.c:1228
1228 handle->outBuffer[handle->outEnd++] = 'g';
(gdb) bt
#0 0x000000000056155f in pgxc_node_send_gxid (handle=0xaebed00, gxid=1749) at pgxcnode.c:1228
#1 0x0000000000565b2f in pgxc_node_begin (conn_count=1, connections=0x7fffc73b0ae0, gxid=1749) at execRemote.c:1452
#2 0x0000000000567bb0 in ExecRemoteQuery (node=0xafe5790) at execRemote.c:2976
#3 0x0000000000537bda in ExecProcNode (node=0xafe5790) at execProcnode.c:465
#4 0x0000000000536962 in ExecutePlan (estate=0xafe51e0, planstate=0xafe5790, operation=CMD_DELETE, numberTuples=0,
direction=NoMovementScanDirection, dest=0xaf789b8) at execMain.c:1520
#5 0x000000000053764c in standard_ExecutorRun (queryDesc=0xafba2d0, direction=ForwardScanDirection, count=0) at execMain.c:312
#6 0x00000000005ed411 in ProcessQuery (plan=0xaf78690, sourceText=0xaf77440 "DELETE FROM uctest WHERE CURRENT OF c1;",
params=<value optimized out>, dest=0xaf789b8, completionTag=0x7fffc73b1360 "") at pquery.c:199
#7 0x00000000005ed619 in PortalRunMulti (portal=0xafe31d0, isTopLevel=1 '\001', dest=0xaf789b8, altdest=0xaf789b8,
completionTag=0x7fffc73b1360 "") at pquery.c:1287
#8 0x00000000005eddd5 in PortalRun (portal=0xafe31d0, count=9223372036854775807, isTopLevel=1 '\001', dest=0xaf789b8,
altdest=0xaf789b8, completionTag=0x7fffc73b1360 "") at pquery.c:837
#9 0x00000000005e9181 in exec_simple_query (query_string=0xaf77440 "DELETE FROM uctest WHERE CURRENT OF c1;")
at postgres.c:1053
#10 0x00000000005ea796 in PostgresMain (argc=4, argv=<value optimized out>, username=0xaeba220 "shench") at postgres.c:3766
#11 0x00000000005c07ac in ServerLoop () at postmaster.c:3607
#12 0x00000000005c29fc in PostmasterMain (argc=7, argv=0xaeb76f0) at postmaster.c:1098
#13 0x000000000056d5ce in main (argc=7, argv=<value optimized out>) at main.c:188
6.expected results:
ERROR: cursor "c1" is not a simply updatable scan of table "uctest"

The bug is from pg_regress.

[mason_s]

Note that WHERE CURRENT OF is currently only safe for cursors declared with SELECT FOR UPDATE

[Koichi Suzuki]

We observed the crash even with FOR UPDATE. Should look into the problem.

[Abbas Butt]

Server crash is fixed by 55433e8be6a7b51568e4d727605b45e911c19f75
The commit only fixes server crash, WHERE CURRENT OF still does not work.

[Abbas Butt]

WHERE CURRENT OF is blocked for now, moving this case to 1.1 Dev Q.

[Koichi Suzuki]

Q2
Will be done as a part of WHERE CURRENT OF