Re: [HACKERS] logical replication - still unstable after all thesemonths

On 2017-05-26 08:58, Simon Riggs wrote:
> On 26 May 2017 at 07:10, Erik Rijkers <er@xs4all.nl> wrote:
> 
>> - Do you agree this number of failures is far too high?
>> - Am I the only one finding so many failures?
> 
> What type of failure are you getting?

The failure is that in the result state the replicated tables differ 
from the original tables.

For instance,

-- out_20170525_0944.txt    100 -- pgbench -c 90 -j 8 -T 60 -P 12 -n   --  scale 25     93 -- All is well.      7 --
Notgood.
 

These numbers mean: the result state of primary and replica is not the 
same, in 7 out of 100 runs.

'not the same state' means:  at least one of the 4 md5's of the sorted 
content of the 4 pgbench tables on the primary is different from those 
taken from the replica.

So, 'failure' means: the 4 pgbench tables on primary and replica are not 
exactly the same after the (one-minute) pgbench-run has finished, and 
logical replication has 'finished'.  (plenty of time is given for the 
replica to catchup. The test only calls 'failure' after 20x waiting (for 
15 seconds) and 20x finding the same erroneous state (erroneous because 
not-same as on primary).


I would really like to know it you think that that doesn't amount to 
'failure'.