Re: Unresolved repliaction hang and stop problem.

On 2021-Jun-16, Ha Ka wrote:

> Here is the upload with generated reports: https://easyupload.io/p38izx
> passwd:  johS5jeewo

OK, so I downloaded that and this is the interesting entry in the
profile for the broken case:

# Samples: 5K of event 'cpu-clock'
# Event count (approx.): 59989898390
#
# Children      Self  Command   Shared Object  Symbol                            
# ........  ........  ........  .............  ..................................
#
   100.00%     0.00%  postgres  postgres       [.] exec_replication_command
            |
            ---exec_replication_command
               WalSndLoop
               XLogSendLogical
               LogicalDecodingProcessRecord
               |          
                --99.51%--ReorderBufferQueueChange
                          |          
                          |--96.06%--hash_seq_search
                          |          
                          |--1.78%--ReorderBufferSerializeTXN
                          |          |          
                          |           --0.52%--errstart
                          |          
                           --0.76%--deregister_seq_scan

What this tells me is that ReorderBufferQueueChange is spending a lot of
time doing hash_seq_search, which probably is the one in
ReorderBufferTXNByXid.

I have, as yet, no idea what this means.

-- 
Álvaro Herrera                            39°49'30"S 73°17'W