Re: [GENERAL] BDR, wal segment has been removed, is it possible move forward? - Mailing list pgsql-general

From milist ujang
Subject Re: [GENERAL] BDR, wal segment has been removed, is it possible move forward?
Date
Msg-id CACG9ogyyJ=usVv0UXz1zWmLwPn_ca9ENGhb805ODOF0WfAkMgg@mail.gmail.com
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In response to Re: [GENERAL] BDR, wal segment has been removed, is it possible move forward?  (Craig Ringer <craig@2ndquadrant.com>)
Responses Re: [GENERAL] BDR, wal segment has been removed, is it possible move forward?
List pgsql-general
Hi Craig

On Wed, Sep 6, 2017 at 7:21 AM, Craig Ringer <craig@2ndquadrant.com> wrote:

BDR can, see bdr.skip_changes_upto .

Unluckily my bdr is 0.9.3
 
But PostgreSQL's logical decoding requires a contiguous WAL stream to maintain a valid catalog_xmin and restart_lsn, so it'll still fail to advance. So your replication from that node is broken, and you have to part the node then rejoin. You'll need to manually recover any diverged data.

Yup, I willing to reconcile data manualy via dblink or else,
is it still possible to move wal segment in 0.9.3?

I've played these at dev env to simulate, but no luck:

# select * from pg_replication_identifier_progress;
 local_id |              external_id               | remote_lsn | local_lsn
----------+----------------------------------------+------------+-----------
        1 | bdr_6461744703437035137_1_34424_30406_ | 0/4288950  | 0/3007588
(1 row)

# SELECT pg_replication_identifier_setup_replaying_from('bdr_6461744703437035137_1_34424_30406_');
 pg_replication_identifier_setup_replaying_from
------------------------------------------------

(1 row)

# SELECT pg_replication_identifier_setup_tx_origin('0/4288960','2017-09-06');
 pg_replication_identifier_setup_tx_origin
-------------------------------------------

(1 row)

# select * from pg_replication_identifier_progress;
 local_id |              external_id               | remote_lsn | local_lsn
----------+----------------------------------------+------------+-----------
        1 | bdr_6461744703437035137_1_34424_30406_ | 0/4288950  | 0/3007588
(1 row)


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