[Tarantool-patches] [PATCH v2 0/5] introduce anonymous replicas

[sergepetrenko]

https://github.com/tarantool/tarantool/tree/sp/gh-3186-anon-replica
https://github.com/tarantool/tarantool/issues/3186

The first patch alters the comment regarding join protocol
to be in sync with latest changes: join isn't done off a snapshot,
but from a read-view rather, created at the moment the request is received.

The second patch removes unnecessary decoding of replicaset uuid on
master side, since master just ignores it now.

The third patch is a preparation for anonymous replica. We need to split join
protocol into two stages: first, fetch a snapshot. This is done by both anonymous
and regular replicas. The second stage is registration, i. e. the addition of
replica to _cluster table. It is done right away when joining a regular replica,
or it can be done by a request from an anonymous replica to transition it to
normal one.
The patch itself just splits applier join into appropriate stages.

The fourth patch modifies vclock logic to ignore 0 component in comparisons.
This is also used by anonymous replicas, which will be the first users of the 
0-th vclock component. This component will be used to keep track of anonymous
replica local changes, which are not replicated. These local changes will vary
from instance to instance, and the anonymous instances will all use 0th component
to track them, so no need to compare this component.

The fifth patch does the main job of adding anonymous replicas.
New requests, FETCH_SNAPSHOT and REGISTER are introduced. Anonymous replicas
are allowed to have a 0 id. They aren't registered as gc consumers and aren't
present in _cluster table.

Changes in v2: 
  - review fixes as per reviews from
    Georgy Kirichenko and Vlad Shpilevoy.

Serge Petrenko (5):
  box: update comment describing join protocol
  replication: do not decode replicaset uuid when processing a subscribe
  applier: split join processing into two stages
  vclock: ignore 0th component in comparisons.
  replication: introduce anonymous replica.

 src/box/applier.cc              | 124 ++++++++++--
 src/box/applier.h               |   4 +
 src/box/box.cc                  | 276 +++++++++++++++++++++++++--
 src/box/box.h                   |  11 +-
 src/box/errcode.h               |   1 +
 src/box/iproto.cc               |  16 +-
 src/box/iproto_constants.h      |   6 +
 src/box/lua/cfg.cc              |  14 +-
 src/box/lua/info.c              |   4 +-
 src/box/lua/load_cfg.lua        |   4 +
 src/box/recovery.cc             |   7 +-
 src/box/relay.cc                |  28 ++-
 src/box/replication.cc          |  41 +++-
 src/box/replication.h           |  24 +++
 src/box/vclock.h                |  12 +-
 src/box/wal.c                   |   4 +
 src/box/xrow.c                  |  49 ++++-
 src/box/xrow.h                  |  68 ++++++-
 test/app-tap/init_script.result |  49 ++---
 test/box/admin.result           |   2 +
 test/box/cfg.result             |   4 +
 test/box/misc.result            |   1 +
 test/replication/anon.lua       |  13 ++
 test/replication/anon.result    | 326 ++++++++++++++++++++++++++++++++
 test/replication/anon.test.lua  | 118 ++++++++++++
 test/replication/anon1.lua      |   1 +
 test/replication/anon2.lua      |   1 +
 test/replication/suite.cfg      |   1 +
 test/unit/vclock.cc             |   8 +-
 29 files changed, 1123 insertions(+), 94 deletions(-)
 create mode 100644 test/replication/anon.lua
 create mode 100644 test/replication/anon.result
 create mode 100644 test/replication/anon.test.lua
 create mode 120000 test/replication/anon1.lua
 create mode 120000 test/replication/anon2.lua

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2.20.1 (Apple Git-117)