From: Sveinn Sveinsson <sveinn.sveinsson@gmail.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: pgsql-bugs@postgresql.org, Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [BUGS] BUG #14657: Server process segmentation fault in v10, May 10th dev snapshot
Date: Thu, 18 May 2017 11:57:59 +0000
Message-ID: <65cbe70a-7be4-dad8-ef44-f268c82b579e@gmail.com> (raw)
In-Reply-To: <6b2fb5ff-40e1-fda3-3ce5-6723e9e5df61@lab.ntt.co.jp>
References: <20170517141151.1435.79890@wrigleys.postgresql.org>
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The patch fixed the problem, thanks a lot.
Regards,
Sveinn.
On fim 18.maí 2017 01:53, Amit Langote wrote:
> On 2017/05/18 10:49, Amit Langote wrote:
>> On 2017/05/18 2:14, Dilip Kumar wrote:
>>> On Wed, May 17, 2017 at 7:41 PM, <sveinn.sveinsson@gmail.com> wrote:
>>>> (gdb) bt
>>>> #0 0x000000000061ab1b in list_nth ()
>>>> #1 0x00000000005e4081 in ExecLockNonLeafAppendTables ()
>>>> #2 0x00000000005f4d52 in ExecInitMergeAppend ()
>>>> #3 0x00000000005e0365 in ExecInitNode ()
>>>> #4 0x00000000005f35a7 in ExecInitLimit ()
>>>> #5 0x00000000005e00f3 in ExecInitNode ()
>>>> #6 0x00000000005dd207 in standard_ExecutorStart ()
>>>> #7 0x00000000006f96d2 in PortalStart ()
>>>> #8 0x00000000006f5c7f in exec_simple_query ()
>>>> #9 0x00000000006f6fac in PostgresMain ()
>>>> #10 0x0000000000475cdc in ServerLoop ()
>>>> #11 0x0000000000692ffa in PostmasterMain ()
>>>> #12 0x0000000000476600 in main ()
>> Thanks for the test case Sveinn and thanks Dilip for analyzing.
>>
>>> Seems like the issue is that the plans under multiple subroots are
>>> pointing to the same partitioned_rels.
>> That's correct.
>>
>>> If I am not getting it wrong "set_plan_refs(PlannerInfo *root, Plan
>>> *plan, int rtoffset)" the rtoffset is specific to the subroot. Now,
>>> problem is that set_plan_refs called for different subroot is updating
>>> the same partition_rel info and make this value completely wrong which
>>> will ultimately make ExecLockNonLeafAppendTables to access the out of
>>> bound "rte" index.
>> Yes.
>>
>>> set_plan_refs
>>> {
>>> [clipped]
>>> case T_MergeAppend:
>>> {
>>> [clipped]
>>>
>>> foreach(l, splan->partitioned_rels)
>>> {
>>> lfirst_int(l) += rtoffset;
>>>
>>>
>>> I think the solution should be that create_merge_append_path make the
>>> copy of partitioned_rels list?
>> Yes, partitioned_rels should be copied.
>>
>>> Attached patch fixes the problem but I am not completely sure about the fix.
>> Thanks for creating the patch, although I think a better fix would be to
>> make get_partitioned_child_rels() do the list_copy. That way, any other
>> users of partitioned_rels will not suffer the same issue. Attached patch
>> implements that, along with a regression test.
>>
>> Added to the open items.
> Oops, forgot to cc -hackers. Patch attached again.
>
> Thanks,
> Amit
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To: pgsql-bugs@postgresql.org
Cc: sveinn.sveinsson@gmail.com, Langote_Amit_f8@lab.ntt.co.jp, dilipbalaut@gmail.com, pgsql-hackers@postgresql.org
Subject: Re: [BUGS] BUG #14657: Server process segmentation fault in v10, May 10th dev snapshot
In-Reply-To: <65cbe70a-7be4-dad8-ef44-f268c82b579e@gmail.com>
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