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From: Konstantin Osipov <kostja@tarantool.org>
To: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: tarantool-patches@freelists.org
Subject: Re: [PATCH 2/3] wal: rollback vclock on write failure
Date: Wed, 27 Jun 2018 20:22:16 +0300	[thread overview]
Message-ID: <20180627172215.GE28358@chai> (raw)
In-Reply-To: <b05491486b91c350fee7656f1af926504e439ac4.1529075903.git.vdavydov.dev@gmail.com>

* Vladimir Davydov <vdavydov.dev@gmail.com> [18/06/15 23:28]:
> In order to determine whether we need to rebootstrap the instance on
> startup, we need to know its vclock. To find it out, we scan the last
> xlog file before proceeding to local recovery, but this means in case
> rebootstrap is not required we scan the last xlog twice, which is
> sub-optimal. To avoid double scan, we can create a new empty xlog before
> shutting down the server and reopen it after restart. However, since we
> promote WAL writer vclock even if xlog write fails, there will be an LSN
> gap between the last xlog and the one created on shutdown in case we
> failed to write last few records. To avoid that, let's rollback WAL
> writer vclock if write fails. BTW this will make it consistent with
> replicaset vclock - see commit 3c4bac715960a ("Follow vclock only for
> success wal writes").

Please add previous xlog's vclock to the next xlog header and use
it to watch gaps/missing xlogs in recover_remaining_wals(). 

If the necessary header is missing, simply ignore the gaps.

Ignore LSN gaps, they are harmless, and using LSN gaps as a mark
of xlog dir corruption was a bad idea from the start.

Logical markers should not be used to verify consistency of the
physical layer.



-- 
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov

  reply	other threads:[~2018-06-27 17:22 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-08 17:34 [PATCH v2 00/11] Replica rejoin Vladimir Davydov
2018-06-08 17:34 ` [PATCH v2 01/11] box: retrieve instance uuid before starting local recovery Vladimir Davydov
2018-06-08 17:51   ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 02/11] box: refactor hot standby recovery Vladimir Davydov
2018-06-08 17:34 ` [PATCH v2 03/11] box: retrieve end vclock before starting local recovery Vladimir Davydov
2018-06-14 12:58   ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 04/11] box: open the port " Vladimir Davydov
2018-06-13 20:43   ` Konstantin Osipov
2018-06-14  8:31     ` Vladimir Davydov
2018-06-14 12:59       ` Konstantin Osipov
2018-06-15 15:48         ` [PATCH 0/3] Speed up recovery in case rebootstrap is not needed Vladimir Davydov
2018-06-15 15:48           ` [PATCH 1/3] xlog: erase eof marker when reopening existing file for writing Vladimir Davydov
2018-06-27 17:09             ` Konstantin Osipov
2018-06-15 15:48           ` [PATCH 2/3] wal: rollback vclock on write failure Vladimir Davydov
2018-06-27 17:22             ` Konstantin Osipov [this message]
2018-06-15 15:48           ` [PATCH 3/3] wal: create empty xlog on shutdown Vladimir Davydov
2018-06-27 17:29             ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 05/11] box: connect to remote peers before starting local recovery Vladimir Davydov
2018-06-13 20:45   ` Konstantin Osipov
2018-06-14  8:34     ` Vladimir Davydov
2018-06-14 12:59       ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 06/11] box: factor out local recovery function Vladimir Davydov
2018-06-13 20:50   ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 07/11] applier: inquire oldest vclock on connect Vladimir Davydov
2018-06-13 20:51   ` Konstantin Osipov
2018-06-14  8:40     ` Vladimir Davydov
2018-06-08 17:34 ` [PATCH v2 08/11] replication: rebootstrap instance on startup if it fell behind Vladimir Davydov
2018-06-13 20:55   ` Konstantin Osipov
2018-06-14  8:58     ` Vladimir Davydov
2018-06-08 17:34 ` [PATCH v2 09/11] vinyl: simplify vylog recovery from backup Vladimir Davydov
2018-06-08 17:34 ` [PATCH v2 10/11] vinyl: pass flags to vy_recovery_new Vladimir Davydov
2018-06-13 20:56   ` Konstantin Osipov
2018-06-08 17:34 ` [PATCH v2 11/11] vinyl: implement rebootstrap support Vladimir Davydov
2018-06-10 12:02   ` Vladimir Davydov

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