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author | Vlad Lesin <vlad_lesin@mail.ru> | 2023-03-06 19:09:13 +0300 |
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committer | Vlad Lesin <vlad_lesin@mail.ru> | 2023-03-10 18:31:10 +0300 |
commit | 7d6b3d40085562d6f9f110f4ba921cf061548844 (patch) | |
tree | 35d675fb57b6e06ab0ddc5e1cde8b13d3c5ad6cb /storage/innobase/include | |
parent | 08267ba0c88d2f3ba1bacee9bb9a1e4da921a60a (diff) | |
download | mariadb-git-7d6b3d40085562d6f9f110f4ba921cf061548844.tar.gz |
MDEV-30775 Performance regression in fil_space_t::try_to_close() introduced in MDEV-23855
fil_node_open_file_low() tries to close files from the top of
fil_system.space_list if the number of opened files is exceeded.
It invokes fil_space_t::try_to_close(), which iterates the list searching
for the first opened space. Then it just closes the space, leaving it in
the same position in fil_system.space_list.
On heavy files opening, like during 'SHOW TABLE STATUS ...' execution,
if the number of opened files limit is reached,
fil_space_t::try_to_close() iterates more and more closed spaces before
reaching any opened space for each fil_node_open_file_low() call. What
causes performance regression if the number of spaces is big enough.
The fix is to keep opened spaces at the top of fil_system.space_list,
and move closed files at the end of the list.
For this purpose fil_space_t::space_list_last_opened pointer is
introduced. It points to the last inserted opened space in
fil_space_t::space_list. When space is opened, it's inserted to the
position just after the pointer points to in fil_space_t::space_list to
preserve the logic, inroduced in MDEV-23855. Any closed space is added
to the end of fil_space_t::space_list.
As opened spaces are located at the top of fil_space_t::space_list,
fil_space_t::try_to_close() finds opened space faster.
There can be the case when opened and closed spaces are mixed in
fil_space_t::space_list if fil_system.freeze_space_list was set during
fil_node_open_file_low() execution. But this should not cause any error,
as fil_space_t::try_to_close() still iterates spaces in the list.
There is no need in any test case for the fix, as it does not change any
functionality, but just fixes performance regression.
Diffstat (limited to 'storage/innobase/include')
-rw-r--r-- | storage/innobase/include/fil0fil.h | 54 |
1 files changed, 51 insertions, 3 deletions
diff --git a/storage/innobase/include/fil0fil.h b/storage/innobase/include/fil0fil.h index af941e359f8..b124f5c6358 100644 --- a/storage/innobase/include/fil0fil.h +++ b/storage/innobase/include/fil0fil.h @@ -906,11 +906,13 @@ public: @param purpose tablespace purpose @param crypt_data encryption information @param mode encryption mode + @param opened true if space files are opened @return pointer to created tablespace, to be filled in with add() @retval nullptr on failure (such as when the same tablespace exists) */ static fil_space_t *create(const char *name, ulint id, ulint flags, fil_type_t purpose, fil_space_crypt_t *crypt_data, - fil_encryption_t mode= FIL_ENCRYPTION_DEFAULT); + fil_encryption_t mode= FIL_ENCRYPTION_DEFAULT, + bool opened= false); MY_ATTRIBUTE((warn_unused_result)) /** Acquire a tablespace reference. @@ -1361,6 +1363,11 @@ struct fil_system_t { private: bool m_initialised; + + /** Points to the last opened space in space_list. Protected with + fil_system.mutex. */ + fil_space_t *space_list_last_opened= nullptr; + #ifdef __linux__ /** available block devices that reside on non-rotational storage */ std::vector<dev_t> ssd; @@ -1405,8 +1412,11 @@ public: /** nonzero if fil_node_open_file_low() should avoid moving the tablespace to the end of space_list, for FIFO policy of try_to_close() */ ulint freeze_space_list; - UT_LIST_BASE_NODE_T(fil_space_t) space_list; - /*!< list of all file spaces */ + + /** List of all file spaces, opened spaces should be at the top of the list + to optimize try_to_close() execution. Protected with fil_system.mutex. */ + UT_LIST_BASE_NODE_T(fil_space_t) space_list; + UT_LIST_BASE_NODE_T(fil_space_t) named_spaces; /*!< list of all file spaces for which a FILE_MODIFY @@ -1422,6 +1432,44 @@ public: has issued a warning about potential space_id reuse */ + /** Add the file to the end of opened spaces list in + fil_system.space_list, so that fil_space_t::try_to_close() should close + it as a last resort. + @param space space to add */ + void add_opened_last_to_space_list(fil_space_t *space); + + /** Move the file to the end of opened spaces list in + fil_system.space_list, so that fil_space_t::try_to_close() should close + it as a last resort. + @param space space to move */ + void move_opened_last_to_space_list(fil_space_t *space) + { + /* In the case when several files of the same space are added in a + row, there is no need to remove and add a space to the same position + in space_list. It can be for system or temporary tablespaces. */ + if (freeze_space_list || space_list_last_opened == space) + return; + + UT_LIST_REMOVE(space_list, space); + + add_opened_last_to_space_list(space); + } + + /** Move closed file last in fil_system.space_list, so that + fil_space_t::try_to_close() iterates opened files first in FIFO order, + i.e. first opened, first closed. + @param space space to move */ + void move_closed_last_to_space_list(fil_space_t *space) + { + if (UNIV_UNLIKELY(freeze_space_list)) + return; + + if (space_list_last_opened == space) + space_list_last_opened= UT_LIST_GET_PREV(space_list, space); + UT_LIST_REMOVE(space_list, space); + UT_LIST_ADD_LAST(space_list, space); + } + /** Return the next tablespace from default_encrypt_tables list. @param space previous tablespace (nullptr to start from the start) @param recheck whether the removal condition needs to be rechecked after |