rocksdb

Commit Graph

Author	SHA1	Message	Date
Andrew Kryczka	b104b87814	Maintain position in range deletions map Summary: When deletion-collapsing mode is enabled (i.e., for DBIter/CompactionIterator), we maintain position in the tombstone maps across calls to ShouldDelete(). Since iterators often access keys sequentially (or reverse-sequentially), scanning forward/backward from the last position can be faster than binary-searching the map for every key. - When Next() is invoked on an iterator, we use kForwardTraversal to scan forwards, if needed, until arriving at the range deletion containing the next key. - Similarly for Prev(), we use kBackwardTraversal to scan backwards in the range deletion map. - When the iterator seeks, we use kBinarySearch for repositioning - After tombstones are added or before the first ShouldDelete() invocation, the current position is set to invalid, which forces kBinarySearch to be used. - Non-iterator users (i.e., Get()) use kFullScan, which has the same behavior as before---scan the whole map for every key passed to ShouldDelete(). Closes https://github.com/facebook/rocksdb/pull/1701 Differential Revision: D4350318 Pulled By: ajkr fbshipit-source-id: 5129b76	8 years ago
Andrew Kryczka	50e305de98	Collapse range deletions Summary: Added a tombstone-collapsing mode to RangeDelAggregator, which eliminates overlap in the TombstoneMap. In this mode, we can check whether a tombstone covers a user key using upper_bound() (i.e., binary search). However, the tradeoff is the overhead to add tombstones is now higher, so at first I've only enabled it for range scans (compaction/flush/user iterators), where we expect a high number of calls to ShouldDelete() for the same tombstones. Point queries like Get() will still use the linear scan approach. Also in this diff I changed RangeDelAggregator's TombstoneMap to use multimap with user keys instead of map with internal keys. Callers sometimes provided ParsedInternalKey directly, from which it would've required string copying to derive an internal key Slice with which we could search the map. Closes https://github.com/facebook/rocksdb/pull/1614 Differential Revision: D4270397 Pulled By: ajkr fbshipit-source-id: 93092c7	8 years ago

Author

SHA1

Message

Date

Andrew Kryczka

b104b87814

Maintain position in range deletions map

Summary:
When deletion-collapsing mode is enabled (i.e., for DBIter/CompactionIterator), we maintain position in the tombstone maps across calls to ShouldDelete(). Since iterators often access keys sequentially (or reverse-sequentially), scanning forward/backward from the last position can be faster than binary-searching the map for every key.

- When Next() is invoked on an iterator, we use kForwardTraversal to scan forwards, if needed, until arriving at the range deletion containing the next key.
- Similarly for Prev(), we use kBackwardTraversal to scan backwards in the range deletion map.
- When the iterator seeks, we use kBinarySearch for repositioning
- After tombstones are added or before the first ShouldDelete() invocation, the current position is set to invalid, which forces kBinarySearch to be used.
- Non-iterator users (i.e., Get()) use kFullScan, which has the same behavior as before---scan the whole map for every key passed to ShouldDelete().
Closes https://github.com/facebook/rocksdb/pull/1701

Differential Revision: D4350318

Pulled By: ajkr

fbshipit-source-id: 5129b76

Andrew Kryczka

50e305de98

Collapse range deletions

Summary:
Added a tombstone-collapsing mode to RangeDelAggregator, which eliminates overlap in the TombstoneMap. In this mode, we can check whether a tombstone covers a user key using upper_bound() (i.e., binary search). However, the tradeoff is the overhead to add tombstones is now higher, so at first I've only enabled it for range scans (compaction/flush/user iterators), where we expect a high number of calls to ShouldDelete() for the same tombstones. Point queries like Get() will still use the linear scan approach.

Also in this diff I changed RangeDelAggregator's TombstoneMap to use multimap with user keys instead of map with internal keys. Callers sometimes provided ParsedInternalKey directly, from which it would've required string copying to derive an internal key Slice with which we could search the map.
Closes https://github.com/facebook/rocksdb/pull/1614

Differential Revision: D4270397

Pulled By: ajkr

fbshipit-source-id: 93092c7

2 Commits (1ba2804b7fae62a179ed1be1deb99981329f2b14)