feat(wal): optimise WAL lag application in case data in order #3151
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puzpuzpuz
reviewed
Apr 4, 2023
ideoma
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Apr 4, 2023
puzpuzpuz
previously approved these changes
Apr 4, 2023
Co-authored-by: Andrei Pechkurov <37772591+puzpuzpuz@users.noreply.github.com>
puzpuzpuz
approved these changes
Apr 4, 2023
[PR Coverage check]😍 pass : 104 / 109 (95.41%) file detail
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When WAL is applied it is copied to the last partition first to speed up the application of smaller transactions. When the WAL is ordered and does not create an out-of-order commit with the existing table data the last partition row count can be extended to make the data visible without waiting for further transactions to be applied.
To do this the format of the designated timestamp column in the last partition WAL LAG area should change from 2 LONGs (timestamp, index pair) to a single LONG (timestamp only). Another part of the change is eagerly extending the last partition row count to when in order WAL is copied into it.