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7e20b49da4
## Problem part of https://github.com/neondatabase/neon/issues/4392, continuation of https://github.com/neondatabase/neon/pull/4408 ## Summary of changes This PR removes all layer objects from LayerMap and moves it to the timeline struct. In timeline struct, LayerFileManager maps a layer descriptor to a layer object, and it is stored in the same RwLock as LayerMap to avoid behavior difference. Key changes: * LayerMap now does not have generic, and only stores descriptors. * In Timeline, we add a new struct called layer mapping. * Currently, layer mapping is stored in the same lock with layer map. Every time we retrieve data from the layer map, we will need to map the descriptor to the actual object. * Replace_historic is moved to layer mapping's replace, and the return value behavior is different from before. I'm a little bit unsure about this part and it would be good to have some comments on that. * Some test cases are rewritten to adapt to the new interface, and we can decide whether to remove it in the future because it does not make much sense now. * LayerDescriptor is moved to `tests` module and should only be intended for unit testing / benchmarks. * Because we now have a usage pattern like "take the guard of lock, then get the reference of two fields", we want to avoid dropping the incorrect object when we intend to unlock the lock guard. Therefore, a new set of helper function `drop_r/wlock` is added. This can be removed in the future when we finish the refactor. TODOs after this PR: fully remove RemoteLayer, and move LayerMapping to a separate LayerCache. all refactor PRs: ``` #4437 --- #4479 ------------ #4510 (refactor done at this point) \-- #4455 -- #4502 --/ ``` --------- Signed-off-by: Alex Chi Z <chi@neon.tech>
Pageserver Benchmarks
How to run
To run all benchmarks:
cargo bench
To run a specific file:
cargo bench --bench bench_layer_map
To run a specific function:
cargo bench --bench bench_layer_map -- real_map_uniform_queries