From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kirill Shcherbatov Subject: [PATCH v4 0/3] box: introduce hint option for memtx tree index Date: Thu, 28 Feb 2019 16:38:46 +0300 Message-Id: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: tarantool-patches@freelists.org, vdavydov.dev@gmail.com Cc: kostja@tarantool.org, Kirill Shcherbatov List-ID: 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 4: -- Code rewritten in C++ with classes. This perform a better maintainability in future. -- New hints for number and boolean types. Memtx Tree is always hinted now. -- INVALID_HINT marker. We need it because double have strange types NaN and so on that musn't be a problem of hints business. -- After part of code was merged, rebased patch. 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 v3: https://www.freelists.org/post/tarantool-patches/PATCH-v3-07-box-introduce-hint-option-for-memtx-tree-index v2: https://www.freelists.org/post/tarantool-patches/PATCH-v2-04-box-introduce-hint-option-for-memtx-tree-index v1: https://www.freelists.org/post/tarantool-patches/PATCH-v1-04-box-introduce-hint-option-for-memtx-tree-index http://github.com/tarantool/tarantool/tree/kshch/gh-3961-tuple-hints https://github.com/tarantool/tarantool/issues/3961 Alexandr Lyapunov (1): memtx: introduce tuple compare hint Kirill Shcherbatov (2): memtx: renamed memtx_tree.c to memtx_tree.cc memtx: rework memtx_tree to store arbitrary nodes src/box/CMakeLists.txt | 3 +- src/box/key_def.c | 2 + src/box/key_def.h | 44 +++ src/box/{memtx_tree.c => memtx_tree.cc} | 406 ++++++++++++++++-------- src/box/tuple_hint.cc | 301 ++++++++++++++++++ src/box/tuple_hint.h | 60 ++++ src/lib/coll/coll.c | 33 ++ src/lib/coll/coll.h | 4 + 8 files changed, 725 insertions(+), 128 deletions(-) rename src/box/{memtx_tree.c => memtx_tree.cc} (68%) create mode 100644 src/box/tuple_hint.cc create mode 100644 src/box/tuple_hint.h -- 2.21.0