Re: Support for N synchronous standby servers - take 2

On Mon, Apr 11, 2016 at 10:58 AM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> On Sat, Apr 9, 2016 at 12:32 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
>>> When I compile now without cassert, I get the compiler warning:
>>
>>> syncrep.c: In function 'SyncRepUpdateConfig':
>>> syncrep.c:878:6: warning: variable 'parse_rc' set but not used
>>> [-Wunused-but-set-variable]
>>
>> If there's a good reason for that to be an Assert, I don't see it.
>> There are no callers of SyncRepUpdateConfig that look like they
>> need to, or should expect not to have to, tolerate errors.
>> I think the way to fix this is to turn the Assert into a plain
>> old test-and-ereport-ERROR.
>>
>
> I've changed the draft patch Amit implemented so that it doesn't parse
> twice(check_hook and assign_hook).
> So assertion that was in assign_hook is no longer necessary.
>
> Please find attached.

Thanks for the patch!

When I emptied s_s_names, reloaded the configration file, set it to 'standby1'
and reloaded the configuration file again, the master crashed with
the following error.

*** glibc detected *** postgres: wal sender process postgres [local]
streaming 0/3015F18: munmap_chunk(): invalid pointer:
0x00000000024d9a40 ***
======= Backtrace: =========
*** glibc detected *** postgres: wal sender process postgres [local]
streaming 0/3015F18: munmap_chunk(): invalid pointer:
0x00000000024d9a40 ***
/lib64/libc.so.6[0x3be8e75f4e]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x97dae2]
======= Backtrace: =========
/lib64/libc.so.6[0x3be8e75f4e]
postgres: wal sender process postgres [local] streaming
0/3015F18(set_config_option+0x12cb)[0x982242]
postgres: wal sender process postgres [local] streaming
0/3015F18(SetConfigOption+0x4b)[0x9827ff]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x97dae2]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x988b4e]
postgres: wal sender process postgres [local] streaming
0/3015F18(set_config_option+0x12cb)[0x982242]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x98af40]
postgres: wal sender process postgres [local] streaming
0/3015F18(SetConfigOption+0x4b)[0x9827ff]
postgres: wal sender process postgres [local] streaming
0/3015F18(ProcessConfigFile+0x9f)[0x98a98b]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x988b4e]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x98af40]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7b50fd]
postgres: wal sender process postgres [local] streaming
0/3015F18(ProcessConfigFile+0x9f)[0x98a98b]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7b359c]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7b50fd]
postgres: wal sender process postgres [local] streaming
0/3015F18(exec_replication_command+0x1a7)[0x7b47b6]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7b359c]
postgres: wal sender process postgres [local] streaming
0/3015F18(PostgresMain+0x772)[0x8141b6]
postgres: wal sender process postgres [local] streaming
0/3015F18(exec_replication_command+0x1a7)[0x7b47b6]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7896f7]
postgres: wal sender process postgres [local] streaming
0/3015F18(PostgresMain+0x772)[0x8141b6]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x788e62]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x7896f7]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x785544]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x788e62]
postgres: wal sender process postgres [local] streaming
0/3015F18(PostmasterMain+0x1134)[0x784c08]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x785544]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x6ce12e]
/lib64/libc.so.6(__libc_start_main+0xfd)[0x3be8e1ed5d]
postgres: wal sender process postgres [local] streaming
0/3015F18(PostmasterMain+0x1134)[0x784c08]
postgres: wal sender process postgres [local] streaming 0/3015F18[0x467e99]

Regards,

--
Fujii Masao