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base repository: postgresql-cfbot/postgresql
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base: cf/5612~1
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head repository: postgresql-cfbot/postgresql
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compare: cf/5612
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  • 2 commits
  • 1 file changed
  • 2 contributors

Commits on Jul 21, 2025

  1. Process sync requests incrementally in AbsorbSyncRequests and Compact… 

    …CheckpointerRequestQueue

If the number of sync requests is big enough, the palloc() call in
AbsorbSyncRequests() will attempt to allocate more than 1 GB of memory,
resulting in failure. This can lead to an infinite loop in the checkpointer
process, as it repeatedly fails to absorb the pending requests.

Similarly, CompactCheckpointerRequestQueue() can face the same memory
allocation issues when the request queue contains millions of entries,
requiring large hash tables that can exceed available memory.

To avoid this, we process requests incrementally in batches in both
functions. This patch introduces bounded memory usage by limiting
allocations to CKPT_REQ_BATCH_SIZE regardless of the total number of
requests. For CompactCheckpointerRequestQueue(), this changes memory
usage from O(num_requests) to O(batch_size) for both hash tables and
skip arrays, while accepting the trade-off that duplicates spanning
batch boundaries won't be detected.

This ensures that memory usage stays within a safe range, avoids
excessive allocations.
    @alterego655
    alterego655 authored and Commitfest Bot committed Jul 21, 2025
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  2. [CF 5612] v7 - Avoid infinite loop in checkpointer 

    This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5612

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/CABPTF7XqUoXmLfS1KxTRyDakaRQ3PWxCb2epyjZnbkDQs-VhBw@mail.gmail.com
Author(s): Maxim Orlov, Xuneng Zhou
    Commitfest Bot committed Jul 21, 2025
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