[RFC PATCH 00/23] vinyl: eliminate read on REPLACE/DELETE

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

This patch set optimizes REPLACE and DELETE operations in vinyl in
presence of secondary indexes: now they don't need to read the primary
key in order to delete the overwritten/deleted tuple from secondary
indexes, instead this job is handed over to primary index compaction
task, while read iterator filters out overwritten tuples that haven't
been purged yet.

The patch set still has a few serious problems (deferred DELETEs
generated by compaction task may be lost on restart; generation of
deferred DELETEs may cause OOM in tx thread) and needs some efforts to
be put in it, but it passes all functional tests should be suitable for
testing and the first round of review. Most patches will stay the same
anyways.

https://github.com/tarantool/tarantool/issues/2129
https://github.com/tarantool/tarantool/commits/dv/gh-2129-vy-eliminate-read-on-replace-delete

Vladimir Davydov (23):
  vinyl: do not turn REPLACE into INSERT when processing DML request
  vinyl: always get full tuple from pk after reading from secondary
    index
  vinyl: use vy_mem_iterator for point lookup
  vinyl: make point lookup always return the latest tuple version
  vinyl: fold vy_replace_one and vy_replace_impl
  vinyl: fold vy_delete_impl
  vinyl: refactor unique check
  vinyl: check key uniqueness before modifying tx write set
  vinyl: remove env argument of vy_check_is_unique_{primary,secondary}
  vinyl: store full tuples in secondary index cache
  xrow: allow to store flags in DML requests
  vinyl: do not pass region explicitly to write iterator functions
  vinyl: fix potential use-after-free in vy_read_view_merge
  test: unit/vy_write_iterator: minor refactoring
  vinyl: teach write iterator to return overwritten tuples
  vinyl: allow to skip certain statements on read
  vinyl: do not free pending tasks on shutdown
  vinyl: store pointer to scheduler in struct vy_task
  vinyl: rename some members of vy_scheduler and vy_task struct
  vinyl: use cbus for communication between scheduler and worker threads
  vinyl: zap vy_scheduler::is_worker_pool_running
  vinyl: rename vy_task::status to is_failed
  vinyl: eliminate read on REPLACE/DELETE

 src/box/iproto_constants.c         |   4 +-
 src/box/iproto_constants.h         |   3 +-
 src/box/vinyl.c                    | 792 +++++++++++++++++++------------------
 src/box/vy_mem.c                   |  19 +-
 src/box/vy_point_lookup.c          |  87 ++--
 src/box/vy_point_lookup.h          |   9 +-
 src/box/vy_read_iterator.c         |  61 ++-
 src/box/vy_read_iterator.h         |  24 ++
 src/box/vy_run.c                   |   7 +-
 src/box/vy_scheduler.c             | 563 ++++++++++++++++++--------
 src/box/vy_scheduler.h             |  41 +-
 src/box/vy_stmt.c                  |   4 +
 src/box/vy_stmt.h                  |  44 +++
 src/box/vy_tx.c                    |  26 ++
 src/box/vy_write_iterator.c        | 173 ++++++--
 src/box/vy_write_iterator.h        |  27 +-
 src/box/xrow.c                     |   8 +
 src/box/xrow.h                     |   2 +
 test/unit/vy_iterators_helper.c    |   5 +
 test/unit/vy_iterators_helper.h    |  12 +-
 test/unit/vy_point_lookup.c        |   4 +-
 test/unit/vy_write_iterator.c      | 319 ++++++++++++---
 test/unit/vy_write_iterator.result |  23 +-
 test/vinyl/info.result             |   5 +
 test/vinyl/info.test.lua           |   3 +
 test/vinyl/layout.result           | 166 +++++---
 test/vinyl/tx_gap_lock.result      |  16 +-
 test/vinyl/tx_gap_lock.test.lua    |  10 +-
 test/vinyl/write_iterator.result   |  11 +-
 test/vinyl/write_iterator.test.lua |   5 +-
 30 files changed, 1615 insertions(+), 858 deletions(-)

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2.11.0