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PostgreSQL 10.0 preview 功能增強 - 邏輯訂閱端 控製參數解說
標簽
PostgreSQL , 10.0 , 邏輯訂閱
背景
PostgreSQL 邏輯訂閱相關文章請參考
《PostgreSQL 10.0 preview 變化 - 邏輯複製pg_hba.conf變化,不再使用replication條目》
《PostgreSQL 10.0 preview 功能增強 - 備庫支持邏輯訂閱,訂閱支持主備漂移了》
《PostgreSQL 10.0 preview 功能增強 - 邏輯複製支持並行COPY初始化數據》
《PostgreSQL 10.0 preview 邏輯複製 - 原理與最佳實踐》
另外10.0新增了兩個參數，用於控製訂閱端的並發。
19.6.4. Subscribers
These settings control the behavior of a logical replication subscriber. Their values on the publisher are irrelevant.
Note that wal_receiver_timeout and wal_retrieve_retry_interval configuration parameters affect the logical replication workers as well.
1. 訂閱端允許同時啟動多少個用於apply與初始表同步的worker進程。
apply指流式同步的worker
初始表同步指邏輯訂閱初始化COPY源端數據的worker進程。
- max_logical_replication_workers (int)
Specifies maximum number of logical replication workers.
This includes both apply workers and table synchronization workers.
Logical replication workers are taken from the pool defined by max_worker_processes.
The default value is 4.
2. 每個訂閱允許的初始化COPY源端數據的並發數，（即同一個訂閱，允許開啟多少個並發，從源端COPY初始數據到訂閱端。）
- max_sync_workers_per_subscription (integer)
Maximum number of synchronization workers per subscription.
This parameter controls the amount of paralelism of the initial data copy during the subscription initialization or when new tables are added.
Currently, there can be only one synchronization worker per table.
The synchronization workers are taken from the pool defined by max_logical_replication_workers.
The default value is 2.
patch如下
Add max_sync_workers_per_subscription to postgresql.conf.sample.
author Fujii Masao <fujii@postgresql.org>
Tue, 11 Apr 2017 23:10:54 +0800 (00:10 +0900)
committer Fujii Masao <fujii@postgresql.org>
Tue, 11 Apr 2017 23:10:54 +0800 (00:10 +0900)
commit ff7bce174390ae063c122ab04020bd4ee070d6ad
tree 12fdc01bc99123086e3693049174dcebd4a06f8b tree | snapshot
parent 1c1a4726eba5bb8c0772db8a8efe0315d71887fb commit | diff
Add max_sync_workers_per_subscription to postgresql.conf.sample.
This commit also does
- add REPLICATION_SUBSCRIBERS into config_group
- mark max_logical_replication_workers and max_sync_workers_per_subscription
as REPLICATION_SUBSCRIBERS parameters
- move those parameters into "Subscribers" section in postgresql.conf.sample
Author: Masahiko Sawada, Petr Jelinek and me
Reported-by: Masahiko Sawada
Discussion: https://postgr.es/m/CAD21AoAonSCoa=v=87ZO3vhfUZA1k_E2XRNHTt=xioWGUa+0ug@mail.gmail.com
這個patch的討論，詳見郵件組，本文末尾URL。
PostgreSQL社區的作風非常嚴謹，一個patch可能在郵件組中討論幾個月甚至幾年，根據大家的意見反複的修正，patch合並到master已經非常成熟，所以PostgreSQL的穩定性也是遠近聞名的。
參考
最後更新：2017-04-22 17:01:48