[pgpool-general: 9121] Re: Another segmentation fault

[Tatsuo Ishii]

> Thank you for the info.  This is really weird. By the time when the
> execution reach here, backend->slots[2] must be filled like slot[0]
> and slot[1] since VALID_BACKEND(2) returns true which means the
> connection to backend 2 is valid. I need more time to investigate
> this.

I am trying to determine the code path when the segfault occurred.  For
this purpose can you share pgpool.conf? I especially interested in
failover_on_backend_error and failover_on_backend_shutdown settings.

Also can you get pgpool.log when segfaults occur with log_min_messages = debug1?

>> For the second crash (in pool_connection_pool.c:326), all slots are null:
>> (gdb) info locals
>> i = 0
>> freed = 0
>> closetime = 0
>> oldestp = 0x7f474f36e168
>> ret = 0x0
>> info = 0x55b511283469 <opt_sort>
>> p = 0x7f474f36e168
>> 
>> (gdb) p *p
>> $7 = {
>>   info = 0x7f47470d5c08,
>>   slots = {0x0 <repeats 128 times>}
>> }
>> 
>> (gdb) p p->slots[0]
>> $10 = (POOL_CONNECTION_POOL_SLOT *) 0x0
>> (gdb) p p->slots[1]
>> $11 = (POOL_CONNECTION_POOL_SLOT *) 0x0
>> (gdb) p p->slots[2]
>> $12 = (POOL_CONNECTION_POOL_SLOT *) 0x0
> 
> This is strange too. How come p->slots[0-2] is 0 if VALID_BACKEND
> returns true. I will look into this.
> 
>> I hope this helps.
>> 
>> Best regards,
>> Emond
>> 
>> Op di 4 jun 2024 om 04:56 schreef Tatsuo Ishii <ishii at sraoss.co.jp>:
>> 
>>> > No worries. I hope you had a good trip. Last night we triggered the last
>>> > crash again. Is there anything we can do to make it easier for you to
>>> find
>>> > the cause?
>>>
>>> It would be helpful if you could share some variable values in the
>>> core file. Since I don't have the pgpool load module when you got the
>>> core, I cannot inspect the variables using the core you provided.
>>>
>>> > #0  connect_backend (sp=0x55803eb0a6b8, frontend=0x55803eb08768) at
>>> > protocol/child.c:1076
>>> > #1  0x000055803ce3d02a in get_backend_connection
>>> (frontend=0x55803eb08768)
>>> > at protocol/child.c:2112
>>> > #2  0x000055803ce38fd5 in do_child (fds=0x55803eabea90) at
>>> > protocol/child.c:416
>>> > #3  0x000055803cdfea4c in fork_a_child (fds=0x55803eabea90, id=13) at
>>> > main/pgpool_main.c:863
>>> > #4  0x000055803cdfde30 in PgpoolMain (discard_status=0 '\000',
>>> > clear_memcache_oidmaps=0 '\000') at main/pgpool_main.c:561
>>> > #5  0x000055803cdfb9e6 in main (argc=2, argv=0x7ffc8cdddda8) at
>>> > main/main.c:365
>>>
>>> Around protocol/child.c:1076:
>>>                                 /* set DB node id */
>>>                                 pool_set_db_node_id(CONNECTION(backend,
>>> i), i);
>>>
>>> I want to see the values in the "backend" struct. Since CONNECTION
>>> macro is used here, you have to do something like in a gdb session.
>>>
>>> p *backend->slots[0]
>>> p *backend->slots[1]
>>> p *backend->slots[2]
>>>
>>> Best reagards,
>>> --
>>> Tatsuo Ishii
>>> SRA OSS LLC
>>> English: http://www.sraoss.co.jp/index_en/
>>> Japanese:http://www.sraoss.co.jp
>>>
> _______________________________________________
> pgpool-general mailing list
> pgpool-general at pgpool.net
> http://www.pgpool.net/mailman/listinfo/pgpool-general