[Enhancement] Reduce lock time of schema change in scenarios with a large number of columns (backport #52800) #52842
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…arge number of columns (#52800) Signed-off-by: trueeyu <[email protected]> (cherry picked from commit f004276)
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trueeyu
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Nov 13, 2024
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Why I'm doing:
This
check compatiblehas a complexity of N^2. In a scenario with many columns (>10000), it will be very slow, causing the table lock to be held for a long time and the import will be stuck.What I'm doing:
Using hash map to replace the link list.
For a table with 20,000 columns, the lock holding time can be optimized from 12s to 0.8s.
TODO: 0.8s is not reasonable. There is still some optimization points and continuous optimization is needed.
What type of PR is this:
Does this PR entail a change in behavior?
If yes, please specify the type of change:
Checklist:
Bugfix cherry-pick branch check:
This is an automatic backport of pull request #52800 done by [Mergify](https://mergify.com). ## Why I'm doing:
This
check compatiblehas a complexity of N^2. In a scenario with many columns (>10000), it will be very slow, causing the table lock to be held for a long time and the import will be stuck.What I'm doing:
Using hash map to replace the link list.
For a table with 20,000 columns, the lock holding time can be optimized from 12s to 0.8s.
TODO: 0.8s is not reasonable. There is still some optimization points and continuous optimization is needed.
What type of PR is this:
Does this PR entail a change in behavior?
If yes, please specify the type of change:
Checklist: