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https://issues.apache.org/jira/browse/HAWQ-1530?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16241605#comment-16241605
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Kuien Liu commented on HAWQ-1530:
---------------------------------
My partner, Zhiyong Dai, has prepared a case to reproduce this issue:
1. Submit "SELECT * FROM tbl" through JDBC client;
2. Send SIGTSTP (by ctrl+z) to suspend JDBC client, when the query in #1 is
running;
3. psql -c 'DROP TABLE tbl', then the request will be hang;
4. psql -c 'select * from tb', the request will be hang as well;
5.When backend finishes query in #1, it replies message to client and HANG at
send() method, we may see following stack info:
#0 0x00007fc8f4972b41 in send () from /lib64/libpthread.so.0
#1 0x000000000078ff9a in secure_write ()
#2 0x000000000079c225 in internal_flush ()
#3 0x000000000079c0e2 in internal_putbytes ()
#4 0x000000000079c457 in pq_putmessage ()
#5 0x000000000079cff3 in pq_endmessage ()
#6 0x00000000004c831c in printtup ()
#7 0x00000000007228b1 in ExecSelect ()
#8 0x00000000007226ec in ExecutePlan ()
#9 0x000000000071e461 in ExecutorRun ()
#10 0x00000000008fa31a in PortalRunSelect ()
#11 0x00000000008f9efa in PortalRun ()
#12 0x00000000008f1458 in exec_execute_message ()
#13 0x00000000008f4f91 in PostgresMain ()
#14 0x000000000089d8a6 in BackendRun ()
#15 0x000000000089cd18 in BackendStartup ()
#16 0x0000000000896e89 in ServerLoop ()
#17 0x0000000000895ea8 in PostmasterMain ()
#18 0x00000000007b1baa in main ()
Wish this helps.
> Illegally killing a JDBC select query causes locking problems
> -------------------------------------------------------------
>
> Key: HAWQ-1530
> URL: https://issues.apache.org/jira/browse/HAWQ-1530
> Project: Apache HAWQ
> Issue Type: Bug
> Components: Transaction
> Reporter: Grant Krieger
> Assignee: Radar Lei
>
> Hi,
> When you perform a long running select statement on 2 hawq tables (join) from
> JDBC and illegally kill the JDBC client (CTRL ALT DEL) before completion of
> the query the 2 tables remained locked even when the query completes on the
> server.
> The lock is visible via PG_locks. One cannot kill the query via SELECT
> pg_terminate_backend(393937). The only way to get rid of it is to kill -9
> from linux or restart hawq but this can kill other things as well.
> The JDBC client I am using is Aqua Data Studio.
> I can provide exact steps to reproduce if required
> Thank you
> Grant
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