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Fix a SingleDelete related optimization for blob indexes (#7904)

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Summary:
There is a small `SingleDelete` related optimization in the
`CompactionIterator` code: when a `SingleDelete`-`Put` pair is preserved
solely for the purposes of transaction conflict checking, the value
itself gets cleared. (This is referred to as "optimization 3" in the
`CompactionIterator` code.) Though the rest of the code got updated to
support `SingleDelete`'ing blob indexes, this chunk was apparently
missed, resulting in an assertion failure (or `ROCKS_LOG_FATAL` in release
builds) when triggered. Note: in addition to clearing the value, we also
need to update the type of the KV to regular value when dealing with
blob indexes here.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7904

Test Plan: `make check`

Reviewed By: ajkr

Differential Revision: D26118009

Pulled By: ltamasi

fbshipit-source-id: 6bf78043d20265e2b15c2e1ab8865025040c42ae
This commit is contained in:
Levi Tamasi 2021-01-29 12:39:44 -08:00 committed by Facebook GitHub Bot
parent 78ee8564ad
commit e5311a8ea4
2 changed files with 22 additions and 2 deletions
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9
db/compaction/compaction_iterator.cc
View File

@ -423,8 +423,8 @@ void CompactionIterator::NextFromInput() {
// In the previous iteration we encountered a single delete that we could
// not compact out. We will keep this Put, but can drop it's data.
// (See Optimization 3, below.)
assert(ikey_.type == kTypeValue);
if (ikey_.type != kTypeValue) {
assert(ikey_.type == kTypeValue || ikey_.type == kTypeBlobIndex);
if (ikey_.type != kTypeValue && ikey_.type != kTypeBlobIndex) {
ROCKS_LOG_FATAL(info_log_,
"Unexpected key type %d for compaction output",
ikey_.type);
@ -437,6 +437,11 @@ void CompactionIterator::NextFromInput() {
current_user_key_snapshot_, last_snapshot);
}
if (ikey_.type == kTypeBlobIndex) {
ikey_.type = kTypeValue;
current_key_.UpdateInternalKey(ikey_.sequence, ikey_.type);
}
value_.clear();
valid_ = true;
clear_and_output_next_key_ = false;

15
db/compaction/compaction_iterator_test.cc
View File

@ -970,6 +970,21 @@ TEST_F(CompactionIteratorWithSnapshotCheckerTest,
2 /*earliest_write_conflict_snapshot*/);
}
// Same as above but with a blob index. In addition to the value getting
// trimmed, the type of the KV is changed to kTypeValue.
TEST_F(CompactionIteratorWithSnapshotCheckerTest,
KeepSingleDeletionForWriteConflictChecking_BlobIndex) {
AddSnapshot(2, 0);
RunTest({test::KeyStr("a", 2, kTypeSingleDeletion),
test::KeyStr("a", 1, kTypeBlobIndex)},
{"", "fake_blob_index"},
{test::KeyStr("a", 2, kTypeSingleDeletion),
test::KeyStr("a", 1, kTypeValue)},
{"", ""}, 2 /*last_committed_seq*/, nullptr /*merge_operator*/,
nullptr /*compaction_filter*/, false /*bottommost_level*/,
2 /*earliest_write_conflict_snapshot*/);
}
// Compaction filter should keep uncommitted key as-is, and
// * Convert the latest velue to deletion, and/or
// * if latest value is a merge, apply filter to all suequent merges.