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On 25/2/19 2:06 μ.μ., Boris Sagadin
wrote:
I think it should. I set it to unlogged on target/slave
server only. One other table which is much smaller and already
replicated receives changes from master.
Ah, ok then.
About settings copy_data to false, nice idea, I'll try that
too and compare speed.
Please note that ppl here tend to not encourage top posting.
Generally It's ok for business emails elsewhere, but here straight
quoting is better and more accurate.
On
25/2/19 9:59 π.μ., Boris Sagadin wrote:
Doing an initial replica.
postgres 119454 93.5 25.9 34613692
32649656 ? Rs 07:16 32:45 \_ postgres:
10/main: bgworker: logical replication worker for
subscription 24783 sync 16500
I've cancelled the sync, set the tables to
unlogged type and started it again. I think it
helped, still much slower than binary, but
better, about 40MB/s. Will set them back to
logged type after initial replica is done.
Will this work at all? Doesn't unlogged mean no changes are
written to the WAL? What if you just copy by dump and then
just add and refresh without copy_data ?
After the initial replica, there aren't that
many updates, so it's OK then. But if a need for
a new slave arises, waiting a few days for
initial replica to finish, which in binary
replication case is just hours, can be a big
problem for us.
On
25/2/19 8:52 π.μ., Boris Sagadin wrote:
Doing an initial replica and trying to
find a bottleneck, Ubuntu 16.04, NVMe disks,
PgSQL v10.7, AWS. With binary replication,
DB is replicated at good speed, around
500MB/s. Trying LR now for a big table
(about 1.4TB with 2 indexes) and the speed
is only about 2MB/s.
Is logical replication subscriber in "streaming"
state or in initial snapshot? What's the behavior
after the initial snapshot, when it gets into
streaming state?
Checked disk util with iostat and only
about 20% utilized on master, 15% on target,
CPU load on master is low. On slave I can
see the "logical replication worker" process
is taking about 70% CPU time on a single
core, machine has 16 cores.
Is there a setting I am missing here? Any
ideas appreciated.
Boris
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
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