From: Georgy Kirichenko <georgy@tarantool.org>
To: tarantool-patches@freelists.org
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>,
Konstantin Osipov <kostja@tarantool.org>
Subject: Re: [tarantool-patches] Re: [PATCH 07/13] memtx: use ref counting to pin indexes for snapshot
Date: Tue, 13 Aug 2019 19:08:53 +0300 [thread overview]
Message-ID: <1764733.5I11P83HaC@localhost> (raw)
In-Reply-To: <20190813105629.GA13834@esperanza>
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On Tuesday, August 13, 2019 1:56:29 PM MSK Vladimir Davydov wrote:
> On Tue, Aug 13, 2019 at 01:24:20AM +0300, Konstantin Osipov wrote:
> > * Vladimir Davydov <vdavydov.dev@gmail.com> [19/08/10 23:22]:
> > > Currently, to prevent an index from going away while it is being
> > > written to a snapshot, we postpone memtx_gc_task's free() invocation
> > > until checkpointing is complete, see commit 94de0a081b3a ("Don't take
> > > schema lock for checkpointing"). This works fine, but makes it rather
> > > difficult to reuse snapshot iterators for other purposes, e.g. feeding
> > > a consistent read view to a newly joined replica.
> > >
> > > Let's instead use index reference counting for pinning indexes for
> > > checkpointing. A reference is taken in a snapshot iterator constructor
> > > and released when the snapshot iterator is destroyed.
> >
> > I don't see how this can work in general, memtx index can not live
> > without memtx space and tuple format. These are not referenced
> > from the index object.
>
> A memtx index doesn't need to reference a space - we move indexes from
> space to sapce on alter without any problems. Regarding the tuple
> format, it is referenced by tuples anyway while tuples are referenced by
> the primary index so we don't need to reference it explicitly.
I believe we should bound all index internal structures and corresponding
tuple together as well as other schema members (spaces, functions, sequences).
It allows us to get rid of crappy alter.cc file and simplifies objects lifetime
around transactional manager (which we do not have yet)
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next prev parent reply other threads:[~2019-08-13 16:08 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-10 10:03 [PATCH 00/13] Join replicas off the current read view Vladimir Davydov
2019-08-10 10:03 ` [PATCH 01/13] vinyl: embed engine in vy_env Vladimir Davydov
2019-08-12 22:14 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:09 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 02/13] vinyl: embed index in vy_lsm Vladimir Davydov
2019-08-12 22:14 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:09 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 03/13] vinyl: move reference counting from vy_lsm to index Vladimir Davydov
2019-08-12 22:16 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:09 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 04/13] vinyl: don't pin index for iterator lifetime Vladimir Davydov
2019-08-10 10:03 ` [PATCH 05/13] vinyl: don't exempt dropped indexes from dump and compaction Vladimir Davydov
2019-08-10 10:03 ` [PATCH 06/13] memtx: don't store pointers to index internals in iterator Vladimir Davydov
2019-08-12 22:21 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:10 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 07/13] memtx: use ref counting to pin indexes for snapshot Vladimir Davydov
2019-08-12 22:24 ` [tarantool-patches] " Konstantin Osipov
2019-08-13 10:56 ` Vladimir Davydov
2019-08-13 16:08 ` Georgy Kirichenko [this message]
2019-08-10 10:03 ` [PATCH 08/13] memtx: allow snapshot iterator to fail Vladimir Davydov
2019-08-12 22:25 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:10 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 09/13] memtx: enter small delayed free mode from snapshot iterator Vladimir Davydov
2019-08-12 22:27 ` [tarantool-patches] " Konstantin Osipov
2019-08-13 10:59 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 10/13] wal: make wal_sync fail on write error Vladimir Davydov
2019-08-12 22:29 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 16:48 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 11/13] xrow: factor out helper for setting REPLACE request body Vladimir Davydov
2019-08-12 22:29 ` [tarantool-patches] " Konstantin Osipov
2019-08-14 13:11 ` Vladimir Davydov
2019-08-10 10:03 ` [PATCH 12/13] test: disable replication/on_schema_init Vladimir Davydov
2019-08-12 22:31 ` [tarantool-patches] " Konstantin Osipov
2019-08-10 10:03 ` [PATCH 13/13] relay: join new replicas off read view Vladimir Davydov
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