mirror of
https://github.com/neondatabase/neon.git
synced 2026-01-15 17:32:56 +00:00
a9bcabe503
part of https://github.com/neondatabase/neon/issues/8002 Due to the limitation of the current layer map implementation, we cannot directly replace a layer. It's interpreted as an insert and a deletion, and there will be file exist error when renaming the newly-created layer to replace the old layer. We work around that by changing the end key of the image layer. A long-term fix would involve a refactor around the layer file naming. For delta layers, we simply skip layers with the same key range produced, though it is possible to add an extra key as an alternative solution. * The image layer range for the layers generated from gc-compaction will be Key::MIN..(Key..MAX-1), to avoid being recognized as an L0 delta layer. * Skip existing layers if it turns out that we need to generate a layer with the same persistent key in the same generation. Note that it is possible that the newly-generated layer has different content from the existing layer. For example, when the user drops a retain_lsn, the compaction could have combined or dropped some records, therefore creating a smaller layer than the existing one. We discard the "optimized" layer for now because we cannot deal with such rewrites within the same generation. --------- Signed-off-by: Alex Chi Z <chi@neon.tech> Co-authored-by: Christian Schwarz <christian@neon.tech>