Make compaction always use the input version with extra ref protection #12992
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jowlyzhang
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Compactionis already creating its own ref for the input Version:rocksdb/db/compaction/compaction.cc
Line 73 in 4b1d595
And properly Unref it during destruction:
rocksdb/db/compaction/compaction.cc
Line 450 in 4b1d595
This PR redirects compaction's access of
cfd->current()to this inputVersion, to prepare for when a column family's data can be replaced all together, andcfd->current()is not safe to access for a compaction job. Because a newVersionwith just some other external files could be installed ascfd->current(). The compaction job's expectation of the currentVersionand the corresponding storage info to always have its input files will no longer be guaranteed.My next follow up is to do a similar thing for flush, also to prepare it for when a column family's data can be replaced. I will make it create its own reference of the current
MemTableListVersionand use it as input, all flush job's access of memtables will be wired to that inputMemTableListVersion. Similarly this reference will be unreffed during a flush job's destruction.Test plan:
Existing tests