Delete reuse space #1539
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Delete reuse space #1539
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The compression must work with previously deleted records with v < 23.12.1
The issue was invalid pointers while deleting multi chunk records. Some pages was defrag while the old pointers pointed to the old place
…record shrunk Issue #1391
The issue was with the missing deletion of the whole linked list segments. Only the head was deleted. This issue was found thanks to the CHECK DATABASE command.
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All tests pass locally. @robfrank when you have time, can you also run it on your Mac? Also, since this is quite impactful, we should try using some large databases to check the back compatibility. At the low level, nothing has changed, just piece of mind before rolling this into v25.2.1. |
This could lead to duplicate entries in the index when the transaction was committed.
This v1 algorithm keeps a list of max 20 pages with statistics of number of records and free space per page. When new space is needed (insert/update), then the list of pages is checked first to recycle space from old pages. The statistics are kept in a json file written at db closing, like the count file. This file is not crucial, can be lost, it's just an approx. cache of free space available.
The algorithm now searches first on the current page for new space
…e way space is reused
… real used records
…n no changes in the database was done
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Pending PR to analyze differences after a long time working on this branch.
This PR is for #1391.