Before it was possible to return stale counter from
StorageMergeTree::totalRows() (that is used for
optimize_trivial_count_query) since the accounting is done in two steps:
- subtract old number of rows
<-- here the number can be zero, even though there are rows -->
- add new number of rows
This was found by CI [1] in 01615_random_one_shard_insertion test:
Here you can see that INSERT went to both tables:
<details>
2022.01.16 09:07:34.288252 [ 154369 ] {a1905be0-93da-460c-8c6f-9b5adace72a0} <Debug> DistributedBlockOutputStream: It took 0.035197041 sec. to insert 100
blocks, 2841.1479249065287 rows per second. Insertion status:
Wrote 54 blocks and 54 rows on shard 0 replica 0, localhost:9000 (average 0 ms per block, the slowest block 1 ms)
Wrote 46 blocks and 46 rows on shard 1 replica 0, localhost:9000 (average 0 ms per block, the slowest block 1 ms)
</details>
But the test fails, since select from shard1.tbl returns 0, and the
problem was concurrent merge:
<details>
2022.01.16 09:07:34.289470 [ 146495 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Debug> executeQuery: (from [::1]:42082) (comment: 01615_random_one_shard_insertion.sql) select count() != 0 from shard_0.tbl;
2022.01.16 09:07:34.289564 [ 375 ] {c7a885fa-4ef4-4dcf-a4de-1650d44fa0ab::all_1_54_9} <Debug> MergeTask::MergeProjectionsStage: Merge sorted 54 rows, containing 1 columns (1 merged, 0 gathered) in 0.00171193 sec., 31543.345814373253 rows/sec., 246.43 KiB>
2022.01.16 09:07:34.289810 [ 375 ] {c7a885fa-4ef4-4dcf-a4de-1650d44fa0ab::all_1_54_9} <Trace> shard_0.tbl (c7a885fa-4ef4-4dcf-a4de-1650d44fa0ab): Renaming temporary part tmp_merge_all_1_54_9 to all_1_54_9.
2022.01.16 09:07:34.289858 [ 146495 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> ContextAccess (default): Access granted: SELECT(number) ON shard_0.tbl
2022.01.16 09:07:34.289897 [ 375 ] {c7a885fa-4ef4-4dcf-a4de-1650d44fa0ab::all_1_54_9} <Trace> shard_0.tbl (c7a885fa-4ef4-4dcf-a4de-1650d44fa0ab) (MergerMutator): Merged 6 parts: from all_1_49_8 to all_54_54_0
2022.01.16 09:07:34.289920 [ 146495 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> InterpreterSelectQuery: WithMergeableState -> Complete
2022.01.16 09:07:34.289987 [ 375 ] {} <Debug> MemoryTracker: Peak memory usage Mutate/Merge: 3.12 MiB.
2022.01.16 09:07:34.290305 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> MergingAggregatedTransform: Reading blocks of partially aggregated data.
2022.01.16 09:07:34.290332 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Debug> MergingAggregatedTransform: Read 1 blocks of partially aggregated data, total 1 rows.
2022.01.16 09:07:34.290343 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> Aggregator: Merging partially aggregated single-level data.
2022.01.16 09:07:34.290358 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> Aggregator: Merged partially aggregated single-level data.
2022.01.16 09:07:34.290366 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Trace> Aggregator: Converting aggregated data to blocks
2022.01.16 09:07:34.290391 [ 154344 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Debug> Aggregator: Converted aggregated data to blocks. 1 rows, 8.00 B in 1.0939e-05 sec. (91416.034 rows/sec., 714.19 KiB/sec.)
2022.01.16 09:07:34.290709 [ 146495 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Information> executeQuery: Read 1 rows, 4.01 KiB in 0.001187722 sec., 841 rows/sec., 3.30 MiB/sec.
2022.01.16 09:07:34.290774 [ 146495 ] {cd9d4cf2-7131-4179-b0b2-3aeec4045755} <Debug> MemoryTracker: Peak memory usage (for query): 0.00 B.
</details>
[1]: https://s3.amazonaws.com/clickhouse-test-reports/33675/7848ea7d609e4c720e8e4494eb6207c0751f5aea/stateless_tests__ubsan__actions_.html
This also fixes a race between DROP TABLE check and INSERT/merges.
v0: use Active parts instead.
v2: fix total counters accounting instead.
- Move some code into module part to avoid dependency from IStorage in SystemLog
- Remove extra headers from SystemLog.h
- Rewrite some code that was relying on headers that was included by SystemLog.h
v2: rebase
v3: squash move into module part with explicit template instantiation
(to make each commit self compilable after rebase)
CI found one hanged query [1], where the problem was that becase of
allow_experimental_parallel_reading_from_replicas the Cancel packet was
read by receivePartitionMergeTreeReadTaskResponseAssumeLocked() and so
the executor was not cancelled, while the code in
MergeTreeBaseSelectProcessor was not ready for this:
<details>
{
"is_initial_query": 0,
"elapsed": 1727.714379573,
"is_cancelled": 0,
"read_rows": "196577",
"read_bytes": "1179462",
"written_rows": "0",
"written_bytes": "0",
"query": "SELECT `CounterID`, `EventDate` FROM `test`.`hits` ORDER BY `CounterID` DESC, `EventDate` ASC LIMIT 50",
...
}
In logs:
2021.12.31 12:11:55.384735 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> executeQuery: (from [::ffff:127.0.0.1]:58094, initial_query_id: e2966ca5-e836-44ef-8f8e-d1c1b32a>
2021.12.31 12:11:55.454379 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Trace> ContextAccess (default): Access granted: SELECT(EventDate, CounterID) ON test.hits
2021.12.31 12:11:55.457583 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Trace> datasets.hits_v1: Parallel reading from replicas enabled true
2021.12.31 12:11:55.459739 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Trace> InterpreterSelectQuery: FetchColumns -> WithMergeableStateAfterAggregationAndLimit
2021.12.31 12:11:55.471048 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> datasets.hits_v1 (SelectExecutor): Key condition: unknown
2021.12.31 12:11:55.476514 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> datasets.hits_v1 (SelectExecutor): MinMax index condition: unknown
2021.12.31 12:11:55.488302 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> datasets.hits_v1 (SelectExecutor): Selected 2/2 parts by partition key, 2 parts by primary key, >
2021.12.31 12:11:55.494020 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> MergeTreeReverseSelectProcessor: Reading 1 ranges in reverse order from part 201403_20_20_0, app>
2021.12.31 12:11:55.497644 [ 101532 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> MergeTreeReverseSelectProcessor: Reading 138 ranges in reverse order from part 201403_19_19_2, a>
2021.12.31 12:11:55.536372 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Compact part, average mark size is 83886080
2021.12.31 12:11:55.558783 [ 171701 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.563960 [ 171701 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.577512 [ 171701 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.585660 [ 171701 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.613694 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.730597 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.743554 [ 171701 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Debug> MergingSortedTransform: Merge sorted 3 blocks, 65567 rows in 0.243999671 sec., 268717.5754429603>
2021.12.31 12:11:55.744196 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.890923 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
2021.12.31 12:11:55.891222 [ 170601 ] {7e5f551e-5960-4fda-9447-9bfdae4660c1} <Test> MergeTreeBaseSelectProcessor: Reading from Wide part, average mark size is 3069
</details>
[1]: https://s3.amazonaws.com/clickhouse-test-reports/33341/0685fd99855bacd0bce02507c00a3bd7709eea61/stress_test__address__actions_.html
The setting allows a user to provide own deduplication semantic in Replicated*MergeTree
If provided, it's used instead of data digest to generate block ID
So, for example, by providing a unique value for the setting in each INSERT statement,
user can avoid the same inserted data being deduplicated
Inserting data within the same INSERT statement are split into blocks
according to the *insert_block_size* settings
(max_insert_block_size, min_insert_block_size_rows, min_insert_block_size_bytes).
Each block with the same INSERT statement will get an ordinal number.
The ordinal number is added to insert_deduplication_token to get block dedup token
i.e. <token>_0, <token>_1, ... Deduplication is done per block
So, to guarantee deduplication for two same INSERT queries,
dedup token and number of blocks to have to be the same
Issue: #7461
It is possible to get empty part in future parts, during merging, that
can be created in case of there is information about this part in
zookeeper, but no replicas has it
(StorageReplicatedMergeTree::createEmptyPartInsteadOfLost())
And this may incorrectly initialize min value, which will be updated
after one more merge (since during that merge there will be no more
information about empty part) or OPTIMIZE.
