db: add implementation warning about requirement imposed by SingleDelete #4343
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db.go line 154 at r1 (raw file):
// flushable are usually in one-to-one correspondence, and atomically // updating the MANIFEST when the flushable is flushed (which ensures the // WAL will never be replayed). There is one exception: a flushableBatch is
Might want to add some words to explain what a flushableBatch is. a flushableBatch (a batch too large to fit in a memtable) ....
The logical memtable splitting idea would also violate the 1:1 correspondence between a flushable and WAL. If we decide to precede with that proposal I think we should find a way to refactor the code to more clearly indicate that a contiguous span of flushables needs to be flushed together. It is subtle the way flushableBatch.readyToFlush() achieves this. I'm pretty sure I'm to blame for that.
Cc @RaduBerinde as he often has good ideas for cleaner implementations.
sumeerbhola
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TFTRs!
Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @pav-kv and @RaduBerinde)
db.go line 154 at r1 (raw file):
Might want to add some words to explain what a flushableBatch is.
a flushableBatch (a batch too large to fit in a memtable) ....
Done
The logical memtable splitting idea would also violate the 1:1 correspondence between a flushable and WAL. If we decide to precede with that proposal I think we should find a way to refactor the code to more clearly indicate that a contiguous span of flushables needs to be flushed together. It is subtle the way
flushableBatch.readyToFlush()achieves this. I'm pretty sure I'm to blame for that.
Ack
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