[PATCH v3 0/7] box: introduce hint option for memtx tree index
Kirill Shcherbatov
kshcherbatov at tarantool.org
Fri Feb 22 18:42:25 MSK 2019
Reworked memtx tree to use 'tuple hints'.
Introduced special functions for retrieve tuple hints for a particular key_def.
Hint is an integer that can be used for tuple comparison optimization:
if a hint of one tuple is less than a hint of another then the first
tuple is definitely less than the second; only if hints are equal
tuple_compare must be called for getting comparison result.
Hints are only useful when:
* they are precalculated and stored along with the tuple;
calculation is not cheap (cheaper than tuple_compare btw) but
precalculated hints allow to compare tuples without even fetching
tuple data.
* first part of key_def is 'string', 'unsigned' or 'integer'
* since hint is calculated using only the first part of key_def
(and only first several characters if it is a string) this part
must be different with high probability for every tuple pair.
Enabled hint option improve performance on average by 15%; Select operations
are significantly accelerated (there are scenarios in which the difference
reaches 200-250%).
Changes in version 3:
-- Better-structured code
-- Refactored all memtx indexes to use shared mempool of default size
-- Refactored all memtx indexes to hide implementation details from headers
-- Moved all hints-related code to corresponding module
-- Better types names, better comments
-- Fixed potential bug with iterators: introduce MEMTX_TREE_IDENTICAL macro
-- Fix inaccurate MEMTX_TREE_ELEM_SET usage in memtx_tree_index_build_next
-- Changed approach to calculate string hints
-- Introduce separate hint for binary collation type
Changes in version 2:
-- Splitted patch to parts in other way to decrease diff
-- Hints are not index option anymore, but default where possible
-- Removed hints for numeric types
v2: https://www.freelists.org/post/tarantool-patches/PATCH-v2-04-box-introduce-hint-option-for-memtx-tree-index
Branch: http://github.com/tarantool/tarantool/tree/kshch/gh-3961-tuple-hints
Issue: https://github.com/tarantool/tarantool/issues/3961
Alexandr Lyapunov (1):
memtx: introduce tuple compare hint
Kirill Shcherbatov (6):
memtx: introduce universal iterator_pool
lib: fix undef _api_name in bps_tree header
lib: introduce BPS_TREE_IDENTICAL custom comparator
memtx: hide index implementation details from header
memtx: rework memtx_tree to store arbitrary nodes
memtx: rename memtx_tree.c to memtx_tree_impl.h
src/box/CMakeLists.txt | 3 +-
src/box/key_def.c | 2 +
src/box/key_def.h | 44 ++
src/box/memtx_bitset.c | 33 +-
src/box/memtx_bitset.h | 26 +-
src/box/memtx_engine.c | 10 +-
src/box/memtx_engine.h | 17 +-
src/box/memtx_hash.c | 58 ++-
src/box/memtx_hash.h | 44 +-
src/box/memtx_rtree.c | 26 +-
src/box/memtx_rtree.h | 16 +-
src/box/memtx_space.c | 16 +-
src/box/memtx_tree.h | 68 +--
src/box/memtx_tree_decl.c | 173 +++++++
src/box/{memtx_tree.c => memtx_tree_impl.h} | 531 ++++++++++++++++----
src/box/tuple_hint.cc | 210 ++++++++
src/box/tuple_hint.h | 51 ++
src/coll.c | 33 ++
src/coll.h | 4 +
src/lib/salad/bps_tree.h | 83 ++-
test/unit/bps_tree_iterator.cc | 16 +-
21 files changed, 1134 insertions(+), 330 deletions(-)
create mode 100644 src/box/memtx_tree_decl.c
rename src/box/{memtx_tree.c => memtx_tree_impl.h} (52%)
create mode 100644 src/box/tuple_hint.cc
create mode 100644 src/box/tuple_hint.h
--
2.20.1
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