Branch: https://github.com/tarantool/tarantool/tree/g.kirichenko/gh-980-disable-lsn-gaps
Issue: https://github.com/tarantool/tarantool/issues/980

On Friday, January 4, 2019 1:34:10 PM MSK you wrote:
> The patchset eliminates LSN gaps from journal what is needed for
> synchronous replication to enforce data stream consistency.
> Replicaset vclock is promoted only after write, replication row applying
> is allowed only if previous row was processed. All conflicting rows to skip
> are replacing with NOPs to fill gaps. After all vclock following
> protected with assert to ensure that this is strict one step increase.
> 
> Needed for: #980
> 
> Georgy Kirichenko (5):
>   Do not promote wal vclock for failed writes
>   Update replicaset vclock from wal
>   Enforce applier out of order protection
>   Emit NOP if an applier skips row
>   Disallow lsn gaps while vclock following
> 
>  src/box/applier.cc                | 113 ++++++++++++++++--------------
>  src/box/box.cc                    |   3 +-
>  src/box/replication.cc            |   2 +
>  src/box/replication.h             |   3 +
>  src/box/vclock.c                  |  16 ++++-
>  src/box/vclock.h                  |   3 +
>  src/box/wal.c                     |  57 ++++++---------
>  src/box/xrow.c                    |   2 +-
>  test/unit/vclock.cc               |  10 +--
>  test/xlog-py/dup_key.result       |  12 +++-
>  test/xlog-py/dup_key.test.py      |  18 +++--
>  test/xlog/errinj.result           |   1 -
>  test/xlog/panic_on_lsn_gap.result |  65 +++++++++--------
>  13 files changed, 167 insertions(+), 138 deletions(-)