pageserver: add metrics for unknown ClearVmBits pages
#9911
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skyzh
approved these changes
Nov 27, 2024
6967 tests run: 6659 passed, 0 failed, 308 skipped (full report)Code coverage* (full report)
* collected from Rust tests only The comment gets automatically updated with the latest test results
f94ee7a at 2024-11-27T17:28:31.342Z :recycle: |
erikgrinaker
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Nov 29, 2024
## Problem When ingesting implicit `ClearVmBits` operations, we silently drop the writes if the relation or page is unknown. There are implicit assumptions around VM pages wrt. explicit/implicit updates, sharding, and relation sizes, which can possibly drop writes incorrectly. Adding a few metrics will allow us to investigate further and tighten up the logic. Touches #9855. ## Summary of changes Add a `pageserver_wal_ingest_clear_vm_bits_unknown` metric to record dropped `ClearVmBits` writes. Also add comments clarifying the behavior of relation sizes on non-zero shards.
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Problem
When ingesting implicit
ClearVmBitsoperations, we silently drop the writes if the relation or page is unknown. There are implicit assumptions around VM pages wrt. explicit/implicit updates, sharding, and relation sizes, which can possibly drop writes incorrectly. Adding a few metrics will allow us to investigate further and tighten up the logic.Touches #9855.
Summary of changes
Add a
pageserver_wal_ingest_clear_vm_bits_unknownmetric to record droppedClearVmBitswrites.Also add comments clarifying the behavior of relation sizes on non-zero shards.