Remove BlockReader::read_blk in favour of BlockCursor
#5015
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1624 tests run: 1551 passed, 0 failed, 73 skipped (full report)The comment gets automatically updated with the latest test results
a1f0143 at 2023-08-25T08:50:14.871Z :recycle: |
This was referenced Aug 17, 2023
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Rebased after merge of #4994 |
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At least in the cases where the concrete type won't be known clearly.
Also, require BlockReader implementors to impl block_cursor.
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## Problem `read_blk` does I/O and thus we would like to make it async. We can't make the function async as long as the `PageReadGuard` returned by `read_blk` isn't `Send`. The page cache is called by `read_blk`, and thus it can't be async without `read_blk` being async. Thus, we have a circular dependency. ## Summary of changes Due to the circular dependency, we convert both the page cache and `read_blk` to async at the same time: We make the page cache use `tokio::sync` synchronization primitives as those are `Send`. This makes all the places that acquire a lock require async though, which we then also do. This includes also asyncification of the `read_blk` function. Builds upon #4994, #5015, #5056, and #5129. Part of #4743.
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Problem
We want to make
read_blkan async function, but outside ofasync_trait, which allocates, and nightly features, we can't use async fn's in traits.Summary of changes
BlockReader::read_blkin favour of using block cursors.BlockReaderRefenum that lists all implementors ofBlockReader::read_blk.BlockReader::read_blkand move its implementations into inherent functions on the types instead.We don't turn
read_blkinto an async fn yet, for that we also need to modify the page cache. So this is a preparatory PR, albeit an important one.Part of #4743.
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