Design of CONVERT PARTITION #56749
Design of CONVERT PARTITION #56749
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| But currently the `EXCHANGE PARTITION` implementation in TiDB allows for concurrent read and write to both the exchanged table and partition, making it complex to support Global Index, where there will need to be a DDL state where one session, S1, sees the new t2 (original p) and the new p (original t2), while another session, S2, might see the original t2 and the original p. Meaning that S2 still needs to double write/update the Global Index of t, when writing to t2 and the S1 also needs to duble write/update the "local" index of t2 when writing to t/p, to keep both table's indexes consistent in the different views of S1 and S2. This makes the DDL extra complex and risky to implement and hard to test. | ||
| Having a way to only allow access to the data of both t/p and t2 through table t during the DDL operation would make it less complex, fewer error handling conditions and also having less performance impact, due to less indexes to keep updated at the same time. | ||
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| So the question is if we should extend the syntax for `EXCHANGE PARTITION` for this new restriction and support Global Index or have a new syntax? |
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Maybe let exchange partition same as MySQL and only supports the feature MySQL had.
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How do you propose to handle the 'swap partition and non-partitioned table' use case, what syntax should be used?
Co-authored-by: Hangjie Mo <mohangjie1995@gmail.com>
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What problem does this PR solve?
Issue Number: ref #45133
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