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.
About settings copy_data to false, nice idea, I'll try that too and compare speed. On Mon, Feb 25, 2019 at 9:51 AM Achilleas Mantzios < ach...@matrix.gatewaynet.com> wrote: > 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. > > Boris > > > On Mon, Feb 25, 2019 at 8:08 AM Achilleas Mantzios < > ach...@matrix.gatewaynet.com> wrote: > >> 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 > >
