On Thu, Jan 31, 2019 at 4:09 PM Achilleas Mantzios < ach...@matrix.gatewaynet.com> wrote:
> On 31/1/19 3:55 μ.μ., Radoslav Nedyalkov wrote: > > Hi All, > > We want to setup a logical replica with initial load from physical > standby. (all pg10.5) > > Basically what we tested is: > > 1.on the master: create publication and logical slot. > > 2.on the standby: pause the stanby. (lsn from 1. is already replayed). > > 3.on the standby: get last replayed lsn, pg_last_wal_replay_lsn(). > > 4.export/import the data into the logical replica. > > 5.on the logical replica: create subscription > with pg_replication_origin_advance'd to the lsn from 3. > > 6.on the logical replica: enable subscription. > > > > On a test setup with some bulk inserts results are encouraging. > > Still we're not that confident. Does the procedure looks okay? > > What if standby is paused at COMMIT lsn? > Who is gonna consume data from the primary's replication slot? If there is > no subscriber connected and reading data, then the primary will think that > the subscriber is down and will accumulate WALs > till some replication client is connected to it (which will not happen > since the subscriber points to the standby). > Yes. that's clear. Primary will accumulate WALs until logical replica connects to it. The point is to offload the primary from massive initial copying. > > Thanks! > > Radoslav Nedyalkov > > > -- > Achilleas Mantzios > IT DEV Lead > IT DEPT > Dynacom Tankers Mgmt > > >
