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Fix an assertion failure in `CompactionOutputs::AddRangeDels()` (#11040) 

Summary:
the [assertion](c3f720c60d/db/compaction/compaction_outputs.cc (L643)) in `CompactionOutputs::AddRangeDels()` can fail after https://github.com/facebook/rocksdb/pull/10802. The assertion fails when `lower_bound_from_range_tombstone` is true during `AddRangeDels()` for a new compaction output file, while the lower bound range tombstone key has seqno 0 and op_type kTypeRangeDeletion. It can have seqno 0 when it was truncated at a point key whose seqno was zeroed out during compaction, the seqno and op_type could be set [here](c3f720c60d/db/compaction/compaction_outputs.cc (L594)). This PR fixes the assertion excluding the case when `lower_bound_from_range_tombstone` is true.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11040

Test Plan: CI

Reviewed By: ajkr

Differential Revision: D42119914

Pulled By: cbi42

fbshipit-source-id: 0897e71b5304cb02aac30f71667b590c37b72baf
This commit is contained in:
Changyu Bi 2022-12-19 16:36:39 -08:00 committed by Facebook GitHub Bot
parent ddad943c29
commit 53b703eafe
1 changed files with 17 additions and 17 deletions
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34
db/compaction/compaction_outputs.cc
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@ -532,23 +532,18 @@ Status CompactionOutputs::AddRangeDels(
// Pretend the smallest key has the same user key as lower_bound
// (the max key in the previous table or subcompaction) in order for
// files to appear key-space partitioned.
//
// When lower_bound is chosen by a subcompaction, we know that
// subcompactions over smaller keys cannot contain any keys at
// lower_bound. We also know that smaller subcompactions exist,
// because otherwise the subcompaction woud be unbounded on the left.
// As a result, we know that no other files on the output level will
// contain actual keys at lower_bound (an output file may have a
// largest key of lower_bound@kMaxSequenceNumber, but this only
// indicates a large range tombstone was truncated). Therefore, it is
// safe to use the tombstone's sequence number, to ensure that keys at
// lower_bound at lower levels are covered by truncated tombstones.
//
// If lower_bound was chosen by the smallest data key in the file,
// choose lowest seqnum so this file's smallest internal key comes
// after the previous file's largest. The fake seqnum is OK because
// the read path's file-picking code only considers user key.
if (lower_bound_from_sub_compact) {
// When lower_bound is chosen by a subcompaction
// (lower_bound_from_sub_compact), we know that subcompactions over
// smaller keys cannot contain any keys at lower_bound. We also know
// that smaller subcompactions exist, because otherwise the
// subcompaction woud be unbounded on the left. As a result, we know
// that no other files on the output level will contain actual keys at
// lower_bound (an output file may have a largest key of
// lower_bound@kMaxSequenceNumber, but this only indicates a large range
// tombstone was truncated). Therefore, it is safe to use the
// tombstone's sequence number, to ensure that keys at lower_bound at
// lower levels are covered by truncated tombstones.
if (ts_sz) {
assert(tombstone.ts_.size() == ts_sz);
smallest_candidate = InternalKey(*lower_bound, tombstone.seq_,
@ -558,6 +553,7 @@ Status CompactionOutputs::AddRangeDels(
InternalKey(*lower_bound, tombstone.seq_, kTypeRangeDeletion);
}
} else if (lower_bound_from_range_tombstone) {
// When lower_bound is chosen from a range tombtone start key:
// Range tombstone keys can be truncated at file boundaries of the files
// that contain them.
//
@ -591,6 +587,10 @@ Status CompactionOutputs::AddRangeDels(
smallest_candidate = range_tombstone_lower_bound_;
}
} else {
// If lower_bound was chosen by the smallest data key in the file,
// choose lowest seqnum so this file's smallest internal key comes
// after the previous file's largest. The fake seqnum is OK because
// the read path's file-picking code only considers user key.
smallest_candidate = InternalKey(*lower_bound, 0, kTypeRangeDeletion);
}
}
@ -640,7 +640,7 @@ Status CompactionOutputs::AddRangeDels(
// it cannot have a seqnum of 0 (unless the smallest data key in a file
// has a seqnum of 0). Otherwise, the truncated tombstone may expose
// deleted keys at lower levels.
assert(smallest_ikey_seqnum == 0 ||
assert(smallest_ikey_seqnum == 0 || lower_bound_from_range_tombstone ||
ExtractInternalKeyFooter(meta.smallest.Encode()) !=
PackSequenceAndType(0, kTypeRangeDeletion));
}