| From: | Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Andres Freund <andres(at)2ndquadrant(dot)com>, Kouhei Kaigai <kaigai(at)ak(dot)jp(dot)nec(dot)com>, Amit Langote <amitlangote09(at)gmail(dot)com>, Fabrízio Mello <fabriziomello(at)gmail(dot)com>, Thom Brown <thom(at)linux(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Parallel Seq Scan |
| Date: | 2015-03-13 08:32:29 |
| Message-ID: | 5502A09D.1040808@lab.ntt.co.jp |
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| Thread: | |
| Lists: | pgsql-hackers |
On 12-03-2015 PM 11:46, Amit Kapila wrote:
> [parallel_seqscan_v10.patch]
There may be a bug in TupleQueueFunnelNext().
1) I observed a hang with stack looking like:
#0 0x00000039696df098 in poll () from /lib64/libc.so.6
#1 0x00000000006f1c6a in WaitLatchOrSocket (latch=0x7f29dc3c73b4,
wakeEvents=1, sock=-1, timeout=0) at pg_latch.c:333
#2 0x00000000006f1aca in WaitLatch (latch=0x7f29dc3c73b4, wakeEvents=1,
timeout=0) at pg_latch.c:197
#3 0x000000000065088b in TupleQueueFunnelNext (funnel=0x17b4a20, nowait=0
'\000', done=0x17ad481 "") at tqueue.c:269
#4 0x0000000000636cab in funnel_getnext (funnelstate=0x17ad3d0) at
nodeFunnel.c:347
...
<snip>
2) In some cases, there can be a segmentation fault with stack looking like:
#0 0x000000396968990a in memcpy () from /lib64/libc.so.6
#1 0x00000000006507e7 in TupleQueueFunnelNext (funnel=0x263c800, nowait=0
'\000', done=0x2633461 "") at tqueue.c:233
#2 0x0000000000636cab in funnel_getnext (funnelstate=0x26333b0) at
nodeFunnel.c:347
#3 0x0000000000636901 in ExecFunnel (node=0x26333b0) at nodeFunnel.c:179
...
<snip>
I could get rid of (1) and (2) with the attached fix.
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