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From: Serge Petrenko <sergepetrenko@tarantool.org>
To: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>,
	tarantool-patches@dev.tarantool.org, gorcunov@gmail.com
Subject: Re: [Tarantool-patches] [PATCH v2 04/10] replication: track registered replica count
Date: Fri, 4 Sep 2020 11:24:53 +0300	[thread overview]
Message-ID: <f53d8c85-5b04-3a4b-a6c8-364b7475acda@tarantool.org> (raw)
In-Reply-To: <78668e078bb8298ad2b88b029fb9d0c5f475956d.1599173312.git.v.shpilevoy@tarantool.org>


04.09.2020 01:51, Vladislav Shpilevoy пишет:
> Struct replicaset didn't store a number of registered replicas.
> Only an array, which was necessary to fullscan each time when want
> to find the count.
>
> That is going to be needed in Raft to calculate election quorum.
> The patch makes the count tracked so as it could be found for
> constant time by simply reading an integer.
>
> Needed for #1146
Thanks for the patch!

LGTM with one comment.

> ---
>   src/box/replication.cc | 3 +++
>   src/box/replication.h  | 7 +++++++
>   2 files changed, 10 insertions(+)
>
> diff --git a/src/box/replication.cc b/src/box/replication.cc
> index ef0e2411d..20f16206a 100644
> --- a/src/box/replication.cc
> +++ b/src/box/replication.cc
> @@ -247,6 +247,7 @@ replica_set_id(struct replica *replica, uint32_t replica_id)
>   						   tt_uuid_str(&replica->uuid));
>   	}
>   	replicaset.replica_by_id[replica_id] = replica;
> +	++replicaset.size;
>   
>   	say_info("assigned id %d to replica %s",
>   		 replica->id, tt_uuid_str(&replica->uuid));
> @@ -267,6 +268,8 @@ replica_clear_id(struct replica *replica)
>   	 * replication.
>   	 */
>   	replicaset.replica_by_id[replica->id] = NULL;
> +	assert(replicaset.size > 0);
> +	--replicaset.size;
>   	if (replica->id == instance_id) {
>   		/* See replica_check_id(). */
>   		assert(replicaset.is_joining);
> diff --git a/src/box/replication.h b/src/box/replication.h
> index ddc2bddf4..69cc820c9 100644
> --- a/src/box/replication.h
> +++ b/src/box/replication.h
> @@ -217,6 +217,13 @@ struct replicaset {
>   	bool is_joining;
>   	/* A number of anonymous replicas following this instance. */
>   	int anon_count;
> +	/**
> +	 * Number of registered replicas. That includes all of them - connected,
> +	 * disconnected, connected not directly, just present in _cluster. If an
> +	 * instance has an ID, has the same replicaset UUID, then it is
> +	 * accounted here.
> +	 */
> +	int size;

We already have `anon_count`. Maybe call this field `registered_count` 
for consistency?
Besides `size` is too general of a term.

>   	/** Applier state. */
>   	struct {
>   		/**

-- 
Serge Petrenko

  reply	other threads:[~2020-09-04  8:24 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03 22:51 [Tarantool-patches] [PATCH v2 00/10] dRaft Vladislav Shpilevoy
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 01/10] applier: store instance_id in struct applier Vladislav Shpilevoy
2020-09-04  8:13   ` Serge Petrenko
2020-09-07 22:54     ` Vladislav Shpilevoy
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 10/10] raft: introduce box.info.raft Vladislav Shpilevoy
2020-09-04 11:38   ` Serge Petrenko
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 02/10] box: introduce summary RO flag Vladislav Shpilevoy
2020-09-04  8:17   ` Serge Petrenko
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 03/10] wal: don't touch box.cfg.wal_dir more than once Vladislav Shpilevoy
2020-09-04  8:20   ` Serge Petrenko
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 04/10] replication: track registered replica count Vladislav Shpilevoy
2020-09-04  8:24   ` Serge Petrenko [this message]
2020-09-07 22:54     ` Vladislav Shpilevoy
2020-09-07 15:45   ` Sergey Ostanevich
2020-09-07 22:54     ` Vladislav Shpilevoy
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 05/10] raft: introduce persistent raft state Vladislav Shpilevoy
2020-09-04  8:59   ` Serge Petrenko
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 06/10] raft: introduce box.cfg.raft_* options Vladislav Shpilevoy
2020-09-04  9:07   ` Serge Petrenko
2020-09-07 22:55     ` Vladislav Shpilevoy
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 07/10] raft: relay status updates to followers Vladislav Shpilevoy
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 08/10] [tosquash] raft: pass source instance_id to raft_process_msg() Vladislav Shpilevoy
2020-09-04  9:22   ` Serge Petrenko
2020-09-03 22:51 ` [Tarantool-patches] [PATCH v2 09/10] raft: introduce state machine Vladislav Shpilevoy
2020-09-04 11:36   ` Serge Petrenko
2020-09-07 22:57     ` Vladislav Shpilevoy
2020-09-09  8:04       ` Serge Petrenko

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