It looks redundant (added in 5ef51ed), though it has "fix tests" in the
log message, but CI reports is not available for the commits from that
PR [1], so let's try.
[1]: https://github.com/ClickHouse/ClickHouse/pull/37543
Also this can be a big problem, since the code under that lock
(throttling or quotas with previous implementation that uses
boost::atomic_shared_ptr) may sleep.
Some numbers:
run | time
------------------------|------
max_threads=100 before | 23.1
max_threads=100 after | 15.1
max_threads=4500 before | 4.5
max_threads=4500 after | 2.3
Query:
select sum(number) from numbers_mt(2000000) settings max_threads=X, max_block_size = 1
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
* Configure keeper for perf tests
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
* Improve performance of SELECTs with active mutations
getAlterMutationCommandsForPart() can be a hot path for query execution
when there are pending mutations.
- LOG_TEST - it is not only check one bool, but actually a bunch of
atomics as well.
- Return std::vector over std::map (map is not required there) - no
changes in performance.
- Copy only RENAME_COLUMN (since only this mutation is required by
AlterConversions).
And here are results:
run|result
-|-
SELECT w/o ALTER|queries: 1565, QPS: 355.259, RPS: 355.259
SELECT w/ ALTER unpatched|queries: 2099, QPS: 220.623, RPS: 220.623
SELECT w/ ALTER and w/o LOG_TEST|queries: 2730, QPS: 235.859, RPS: 235.859
SELECT w/ ALTER and w/o LOG_TEST and w/ RENAME_COLUMN only|queries: 2995, QPS: 290.982, RPS: 290.982
But there are still room for improvements, at least MergeTree engines
could implement getStorageSnapshotForQuery().
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
* Add AlterConversions::supportsMutationCommandType(), flatten vector<vector<MutationCommand>>
* Work around what appears to be a clang static analysis bug
---------
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
Co-authored-by: Michael Kolupaev <michael.kolupaev@clickhouse.com>
* reuse result of functionfactory::get
* add perf test
* Update src/Functions/coalesce.cpp
Co-authored-by: János Benjamin Antal <antaljanosbenjamin@users.noreply.github.com>
* change as requested
---------
Co-authored-by: János Benjamin Antal <antaljanosbenjamin@users.noreply.github.com>
