Re: [PATCH] Reuse Workers and Replication Slots during Logical Replication

Hi Melih,

FYI -- The same testing was repeated but this time PG was configured
to say synchronous_commit=on. Other factors and scripts were the same
as before --- busy apply, 5 runs, 4 workers, 1000 inserts/tx, 100
empty tables, etc.

There are still more xlog records seen for the v26 patch, but now the
v26 performance was better than HEAD.

RESULTS (synchronous_commit=on)
---------------------------------------------------

Xlog Counts

HEAD
postgres=# select avg(counttime) "avg", median(counttime) "median",
min(counttime) "min", max(counttime) "max", logtype from test_head
group by logtype;
          avg          |        median         | min | max  |
   logtype
-----------------------+-----------------------+-----+------+-----------
-----------------------+-----------------------+-----+------+-----------
-----------------------+-----------------------+-----+------+-----------
1253.7509433962264151 | 1393.0000000000000000 |   1 | 2012 |
FIND_DECODING_XLOG_RECORD_COUNT
(1 row)


HEAD+v26-0001
postgres=# select avg(counttime) "avg", median(counttime) "median",
min(counttime) "min", max(counttime) "max", logtype from test_v26
group by logtype;
          avg          |        median         | min | max  |
   logtype
-----------------------+-----------------------+-----+------+-----------
-----------------------+-----------------------+-----+------+-----------
-----------------------+-----------------------+-----+------+-----------
1278.4075471698113208 | 1423.5000000000000000 |   1 | 2015 |
FIND_DECODING_XLOG_RECORD_COUNT
(1 row)

~~~~~~

Performance

HEAD
[peter@localhost res_0809_vignesh_timing_sync_head]$ cat *.dat_SUB |
grep RESULT | grep -v duration | awk '{print $3}'
4014.266
3892.089
4195.318
3571.862
4312.183


HEAD+v26-0001
[peter@localhost res_0809_vignesh_timing_sync_v260001]$ cat *.dat_SUB
| grep RESULT | grep -v duration | awk '{print $3}'
3326.627
3213.028
3433.611
3299.803
3258.821

------
Kind Regards,
Peter Smith.
Fujitsu Australia