Fix backward scan flag for parallel queries #1604
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added 5 commits
July 11, 2023 15:24
Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash. In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation. Signed-off-by: Robin Li <[email protected]>
| select set_config('min_parallel_table_scan_size', 0, false); | ||
| GO | ||
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||
| select a, count(*) from t_babel4261 group by a order by 2; -- should not crash |
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could you use
SET BABELFISH_STATISTICS PROFILE ON
at this test place, to explicit show it's a parallel query plan at here
| select a, count(*) from t_babel4261 group by a order by 2; -- should not crash | ||
| GO | ||
|
|
||
| DROP TABLE t_babel4261; |
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select set_config('parallel_setup_cost', 0, false);
select set_config('parallel_tuple_cost', 0, false);
select set_config('min_parallel_table_scan_size', 0, false);
could you set those three parameters back to default value in this place
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I'm not quite sure how to set them back since I don't know what the default value is. Also, it seems that in this test
they are not set back. So I guess not setting them back is okay?There was a problem hiding this comment.
No it's not, 3294 didn't do the right thing in here
EXEC sp_babelfish_configure 'babelfishpg_tsql.xxxx', 'default';
Would you try this to reset.
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I tried doing that, but it doesn't seem to work:
1> EXEC sp_babelfish_configure 'babelfishpg_tsql.parallel_setup_cost', 'default';
2> go
Msg 33557097, Level 16, State 1, Server BABELFISH, Line 1
unknown configuration: babelfishpg_tsql.parallel_setup_cost
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I have done this by putting set_config in a transaction and make the third parameter true, so that the configurations will be set back to default when the transaction is committed.
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Jul 12, 2023
rl626
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Jul 12, 2023
…#1604) * Fix backward scan flag for parallel queries Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash. In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation. Task: BABEL-4261, BABEL-4281 Signed-off-by: Robin Li <[email protected]>
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Nov 9, 2023
…#1604) * Fix backward scan flag for parallel queries Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash. In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation. Task: BABEL-4261, BABEL-4281 Signed-off-by: Robin Li <[email protected]>
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rohit01010
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Nov 9, 2023
…stgresql#1604)" This reverts commit f339cff. Signed-off-by: Rohit Bhagat <[email protected]>
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…#1604) Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash. In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation. Task: BABEL-4261, BABEL-4281 Signed-off-by: Robin Li <[email protected]>
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Deepesh125
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Nov 10, 2023
* Fix backward scan flag for parallel queries (#1604) Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash. In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation. Task: BABEL-4261, BABEL-4281 Authored-by: Robin Li <[email protected]> Signed-off-by: Rohit Bhagat <[email protected]>
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Description
Currently there is a bug in Babelfish that allows the backward scan flag to be set for parallel queries. However, backward scans cannot be parallelized. This bug results in assertion failures in the Postgres engine and leads Babelfish queries to crash.
Issues Resolved
In this commit, we fix the issue by disallowing backward scan flag to be set when a query is in parallel mode. This issue occurs during the implementation of full text search in Babelfish. Fixing the issue unblocks full text search implementation.
Check List
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