mirror of
https://github.com/neondatabase/neon.git
synced 2026-01-05 20:42:54 +00:00
3a6fa76828
In general, tiered compaction is splitting delta layers along the key dimension, but this can only continue until a single key is reached: if the changes from a single key don't fit into one layer file, we used to create layer files of unbounded sizes. This patch implements the method listed as TODO/FIXME in the source code. It does the following things: * Make `accum_key_values` take the target size and if one key's modifications exceed it, make it fill `partition_lsns`, a vector of lsns to use for partitioning. * Have `retile_deltas` use that `partition_lsns` to create delta layers separated by lsn. * Adjust the `test_many_updates_for_single_key` to allow layer files below 0.5 the target size. This situation can create arbitarily small layer files: The amount of data is arbitrary that sits between having just cut a new delta, and then stumbling upon the key that needs to be split along lsn. This data will end up in a dedicated layer and it can be arbitrarily small. * Ignore single-key delta layers for depth calculation: in theory we might have only single-key delta layers in a tier, and this might confuse depth calculation as well, but this should be unlikely. Fixes #7243 Part of #7554 --------- Co-authored-by: Heikki Linnakangas <heikki@neon.tech>