Re: Should we remove "not fast" promotion at all?
От | Tomonari Katsumata |
---|---|
Тема | Re: Should we remove "not fast" promotion at all? |
Дата | |
Msg-id | 52045EB1.6020809@po.ntts.co.jp обсуждение исходный текст |
Ответ на | Re: Should we remove "not fast" promotion at all? (Josh Berkus <josh@agliodbs.com>) |
Список | pgsql-hackers |
Hi, I understood it's too late to change the feature. I hope it will be revised in 9.4! (2013/08/09 4:13), Josh Berkus wrote:> On 08/08/2013 11:01 AM, Andres Freund wrote:>>> I don't think anybody working on relatedareas of the code thinks it's>> rock solid.>> But anyway, I just don't see the downside of allowing problem>> analysis.You're free to do more testing, review, whatever before the>> release.>> I'm 100% with you that we ought to keepthe slow failover code around> and accessible to debugging. What I'm asking is whether it should still> be explicitlyavailable to users, and the default. Based on your> feedback, it's sounding like it should be.> In my opinion, the default behavior "fast promote" is ok. Because we don't have any explicit problem with it for now. And we shouldn't mention about "normal promote" in document. I think it will make user confused if do so. By the way, I'm thinking about when these trigger files(*) are unlinked. (*)Now I treat these three files 1) a file specified in trigger_file 2) ${PGDATA}/promote 3) ${PGDATA}/fast_promote Current source has a problem in some corner cases. It occurs by the timing of detecting these files. for example: ------ case1: createing 1) and executing "pg_ctl promote" occur at the same time. case2: creating 1) and promoting at recovery-end(by recovery_target_xxx) occur at the same time. ------ 1) is created, but promoting completes by another trigger. Both cases 1) remains on the server. If user doesn't know it and make a standby on the server, the standby will promote soon. I think this is not so big problem, but not user-friendly. Against this, I'm thinking unlinking these files before starting recovery. This should be fixed in 9.4 too? --------- Tomonari Katsumata
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