[PATCH v3 00/11] Replica rejoin

[Vladimir Davydov <vdavydov.dev@gmail.com>]

After this patch set is applied, an instance will try to detect if
it fell too much behind its peers in the cluster and so needs to be
rebootstrapped. If it does, it will skip local recovery and instead
proceed to bootstrap from a remote master. Old files (xlog, snap)
are not deleted during rebootstrap. They will be removed by gc as
usual.

https://github.com/tarantool/tarantool/issues/461
https://github.com/tarantool/tarantool/commits/dv/gh-461-replica-rejoin

Changes in v3:
 - Remove merged patches, add some new ones.
 - Rebase on top of the latest 1.10: this required patching gc to make
   it track vclocks instead of signatures so that it could report the
   vclock of the oldest xlog stored on the instance.
 - Follow-up on the recently committed patch for recovery subsystem: add
   some comments and remove double scanning of the WAL directory.
 - Introduce a new IPROTO command, IPROTO_REQUEST_STATUS, to be used
   instead of IPROTO_REQUEST_VOTE; send a map in reply to this command.
   Rationale: a map is more flexible and can be extended. In particular,
   we can use the very same message for inquiring the oldest vclock
   stored on the master to detect if a replica needs to be rejoined,
   instead of introducing a new IPROTO command, as we did in v2.
 - Do NOT rebootstrap a replica if it has some data that is absent on
   the master. Rationale: we don't want to lose ANY data by rejoining a
   replica; besides, if a replica's vclock is incomparable with the
   master's, xdir_scan may break.

v2: https://www.freelists.org/post/tarantool-patches/PATCH-v2-0011-Replica-rejoin

Changes in v2:
 - Implement rebootstrap support for vinyl engine.
 - Call recover_remaining_wals() explicitly after recovery_stop_local()
   as suggested by @kostja.
 - Add comment to memtx_engine_new() explaining why we need to init
   INSTANCE_UUID before proceeding to local recovery.

v1: https://www.freelists.org/post/tarantool-patches/RFC-PATCH-0012-Replica-rejoin

Vladimir Davydov (11):
  recovery: clean up WAL dir scan code
  xrow: factor out function for decoding vclock
  Introduce IPROTO_REQUEST_STATUS command
  Get rid of IPROTO_SERVER_IS_RO
  gc: keep track of vclocks instead of signatures
  Include oldest vclock available on the instance in IPROTO_STATUS
  replication: rebootstrap instance on startup if it fell behind
  vinyl: simplify vylog recovery from backup
  vinyl: pass flags to vy_recovery_new
  Update test-run
  vinyl: implement rebootstrap support

 src/box/applier.cc                       |   6 +-
 src/box/applier.h                        |   8 +-
 src/box/box.cc                           |  26 +++-
 src/box/box.h                            |   3 +
 src/box/gc.c                             |  89 ++++++-----
 src/box/gc.h                             |  23 +--
 src/box/iproto.cc                        |  16 +-
 src/box/iproto_constants.c               |   4 +-
 src/box/iproto_constants.h               |  15 +-
 src/box/lua/info.c                       |   4 +-
 src/box/recovery.cc                      |   2 +-
 src/box/recovery.h                       |   7 +-
 src/box/relay.cc                         |  21 +--
 src/box/replication.cc                   |  36 ++++-
 src/box/replication.h                    |   9 ++
 src/box/vinyl.c                          |   8 +-
 src/box/vy_log.c                         | 207 ++++++++++++++++++-------
 src/box/vy_log.h                         |  50 +++++-
 src/box/wal.c                            |   9 ++
 src/box/xrow.c                           | 179 +++++++++++++++------
 src/box/xrow.h                           | 106 +++++++------
 src/errinj.h                             |   1 +
 test-run                                 |   2 +-
 test/box/errinj.result                   |   6 +-
 test/replication/replica_rejoin.result   | 250 ++++++++++++++++++++++++++++++
 test/replication/replica_rejoin.test.lua |  91 +++++++++++
 test/vinyl/replica_rejoin.lua            |  13 ++
 test/vinyl/replica_rejoin.result         | 257 +++++++++++++++++++++++++++++++
 test/vinyl/replica_rejoin.test.lua       |  88 +++++++++++
 test/vinyl/suite.ini                     |   2 +-
 30 files changed, 1293 insertions(+), 245 deletions(-)
 create mode 100644 test/replication/replica_rejoin.result
 create mode 100644 test/replication/replica_rejoin.test.lua
 create mode 100644 test/vinyl/replica_rejoin.lua
 create mode 100644 test/vinyl/replica_rejoin.result
 create mode 100644 test/vinyl/replica_rejoin.test.lua

-- 
2.11.0