Commit graph

14 commits

Author SHA1 Message Date
Maysam Yabandeh b225de7e10 WritePrepared Txn: smallest_prepare optimization
Summary:
The is an optimization to reduce lookup in the CommitCache when querying IsInSnapshot. The optimization takes the smallest uncommitted data at the time that the snapshot was taken and if the sequence number of the read data is lower than that number it assumes the data as committed.
To implement this optimization two changes are required: i) The AddPrepared function must be called sequentially to avoid out of order insertion in the PrepareHeap (otherwise the top of the heap does not indicate the smallest prepare in future too), ii) non-2PC transactions also call AddPrepared if they do not commit in one step.
Closes https://github.com/facebook/rocksdb/pull/3649

Differential Revision: D7388630

Pulled By: maysamyabandeh

fbshipit-source-id: b79506238c17467d590763582960d4d90181c600
2018-04-02 20:27:41 -07:00
Siying Dong 821e0b1683 Disable options_settable_test in UBSAN and fix UBSAN failure in blob_…
Summary:
…db_test

options_settable_test won't pass UBSAN so disable it.
blob_db_test fails in UBSAN as SnapshotList doesn't initialize all the fields in dummy snapshot. Fix it. I don't understand why only blob_db_test fails though.
Closes https://github.com/facebook/rocksdb/pull/3477

Differential Revision: D6928681

Pulled By: siying

fbshipit-source-id: e31dd300fcdecdfd4f6af279a0987fd0cdec5122
2018-02-07 14:42:26 -08:00
Yi Wu 237b292515 BlobDB: Remove the need to get sequence number per write
Summary:
Previously we store sequence number range of each blob files, and use the sequence number range to check if the file can be possibly visible by a snapshot. But it adds complexity to the code, since the sequence number is only available after a write. (The current implementation get sequence number by calling GetLatestSequenceNumber(), which is wrong.) With the patch, we are not storing sequence number range, and check if snapshot_sequence < obsolete_sequence to decide if the file is visible by a snapshot (previously we check if first_sequence <= snapshot_sequence < obsolete_sequence).
Closes https://github.com/facebook/rocksdb/pull/3274

Differential Revision: D6571497

Pulled By: yiwu-arbug

fbshipit-source-id: ca06479dc1fcd8782f6525b62b7762cd47d61909
2017-12-15 13:27:30 -08:00
Yi Wu 7bfa88037e Blob DB: fix snapshot handling
Summary:
Blob db will keep blob file if data in the file is visible to an active snapshot. Before this patch it checks whether there is an active snapshot has sequence number greater than the earliest sequence in the file. This is problematic since we take snapshot on every read, if it keep having reads, old blob files will not be cleanup. Change to check if there is an active snapshot falls in the range of [earliest_sequence, obsolete_sequence) where obsolete sequence is
1. if data is relocated to another file by garbage collection, it is the latest sequence at the time garbage collection finish
2. otherwise, it is the latest sequence of the file
Closes https://github.com/facebook/rocksdb/pull/3087

Differential Revision: D6182519

Pulled By: yiwu-arbug

fbshipit-source-id: cdf4c35281f782eb2a9ad6a87b6727bbdff27a45
2017-11-02 15:58:27 -07:00
Maysam Yabandeh fbfa3e7a43 WriteAtPrepare: Efficient read from snapshot list
Summary:
Divide the old snapshots to two lists: a few that fit into a cached array and the rest in a vector, which is expected to be empty in normal cases. The former is to optimize concurrent reads from snapshots without requiring locks. It is done by an array of std::atomic, from which std::memory_order_acquire reads are compiled to simple read instructions in most of the x86_64 architectures.
Closes https://github.com/facebook/rocksdb/pull/2758

Differential Revision: D5660504

Pulled By: maysamyabandeh

fbshipit-source-id: 524fcf9a8e7f90a92324536456912a99aaa6740c
2017-08-26 01:00:38 -07:00
Maysam Yabandeh eb6425303e Update WritePrepared with the pseudo code
Summary:
Implement the main body of WritePrepared pseudo code. This includes PrepareInternal and CommitInternal, as well as AddCommitted which updates the commit map. It also provides a IsInSnapshot method that could be later called form the read path to decide if a version is in the read snapshot or it should other be skipped.

This patch lacks unit tests and does not attempt to offer an efficient implementation. The idea is that to have the API specified so that we can work on related tasks in parallel.
Closes https://github.com/facebook/rocksdb/pull/2713

Differential Revision: D5640021

Pulled By: maysamyabandeh

fbshipit-source-id: bfa7a05e8d8498811fab714ce4b9c21530514e1c
2017-08-16 16:57:47 -07:00
Siying Dong 3c327ac2d0 Change RocksDB License
Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75
2017-07-15 16:11:23 -07:00
Siying Dong d616ebea23 Add GPLv2 as an alternative license.
Summary: Closes https://github.com/facebook/rocksdb/pull/2226

Differential Revision: D4967547

Pulled By: siying

fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4
2017-04-27 18:06:12 -07:00
Baraa Hamodi 21e95811d1 Updated all copyright headers to the new format. 2016-02-09 15:12:00 -08:00
agiardullo 3bfd3d39a3 Use SST files for Transaction conflict detection
Summary:
Currently, transactions can fail even if there is no actual write conflict.  This is due to relying on only the memtables to check for write-conflicts.  Users have to tune memtable settings to try to avoid this, but it's hard to figure out exactly how to tune these settings.

With this diff, TransactionDB will use both memtables and SST files to determine if there are any write conflicts.  This relies on the fact that BlockBasedTable stores sequence numbers for all writes that happen after any open snapshot.  Also, D50295 is needed to prevent SingleDelete from disappearing writes (the TODOs in this test code will be fixed once the other diff is approved and merged).

Note that Optimistic transactions will still rely on tuning memtable settings as we do not want to read from SST while on the write thread.  Also, memtable settings can still be used to reduce how often TransactionDB needs to read SST files.

Test Plan: unit tests, db bench

Reviewers: rven, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb, yoshinorim

Differential Revision: https://reviews.facebook.net/D50475
2015-12-11 12:34:11 -08:00
agiardullo e5c5f23814 Support marking snapshots for write-conflict checking - Take 2
Summary:
D51183 was reverted due to breaking the LITE build.

This diff is the same as D51183 but with a fix for the LITE BUILD(D51693)

Test Plan: run all unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51711
2015-12-08 16:47:31 -08:00
sdong 1d63c3d610 Revert "Support marking snapshots for write-conflict checking"
This reverts commit ec704aafdc for it broke RocksDB LITE build.
2015-12-08 09:27:17 -08:00
agiardullo ec704aafdc Support marking snapshots for write-conflict checking
Summary:
D50475 enables using SST files for transaction write-conflict checking.  In order for this to work, we need to make sure not to compact out SingleDeletes when there is an earlier transaction snapshot(D50295).  If there is a long-held snapshot, this could reduce the benefit of the SingleDelete optimization.

This diff allows Transactions to mark snapshots as being used for write-conflict checking.  Then, during compaction, we will be able to optimize SingleDeletes better in the future.

This diff adds a flag to SnapshotImpl which is used by Transactions.  This diff also passes the earliest write-conflict snapshot's sequence number to CompactionIterator.  This diff does not actually change Compaction (after this diff is pushed, D50295 will be able to use this information).

Test Plan: no behavior change, ran existing tests

Reviewers: rven, kradhakrishnan, yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51183
2015-12-07 19:40:51 -08:00
agiardullo 16ea1c7d1c simple ManagedSnapshot wrapper
Summary: Implemented this simple wrapper for something else I was working on.  Seemed like it makes sense to expose it instead of burying it in some random code.

Test Plan: added test

Reviewers: rven, kradhakrishnan, sdong, yhchiang

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43293
2015-08-06 17:59:05 -07:00
Renamed from db/snapshot.h (Browse further)