Commit Graph

28 Commits

Author SHA1 Message Date
Mike Kolupaev
b4d7209428 Add an option to put first key of each sst block in the index (#5289)
Summary:
The first key is used to defer reading the data block until this file gets to the top of merging iterator's heap. For short range scans, most files never make it to the top of the heap, so this change can reduce read amplification by a lot sometimes.

Consider the following workload. There are a few data streams (we'll be calling them "logs"), each stream consisting of a sequence of blobs (we'll be calling them "records"). Each record is identified by log ID and a sequence number within the log. RocksDB key is concatenation of log ID and sequence number (big endian). Reads are mostly relatively short range scans, each within a single log. Writes are mostly sequential for each log, but writes to different logs are randomly interleaved. Compactions are disabled; instead, when we accumulate a few tens of sst files, we create a new column family and start writing to it.

So, a typical sst file consists of a few ranges of blocks, each range corresponding to one log ID (we use FlushBlockPolicy to cut blocks at log boundaries). A typical read would go like this. First, iterator Seek() reads one block from each sst file. Then a series of Next()s move through one sst file (since writes to each log are mostly sequential) until the subiterator reaches the end of this log in this sst file; then Next() switches to the next sst file and reads sequentially from that, and so on. Often a range scan will only return records from a small number of blocks in small number of sst files; in this case, the cost of initial Seek() reading one block from each file may be bigger than the cost of reading the actually useful blocks.

Neither iterate_upper_bound nor bloom filters can prevent reading one block from each file in Seek(). But this PR can: if the index contains first key from each block, we don't have to read the block until this block actually makes it to the top of merging iterator's heap, so for short range scans we won't read any blocks from most of the sst files.

This PR does the deferred block loading inside value() call. This is not ideal: there's no good way to report an IO error from inside value(). As discussed with siying offline, it would probably be better to change InternalIterator's interface to explicitly fetch deferred value and get status. I'll do it in a separate PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5289

Differential Revision: D15256423

Pulled By: al13n321

fbshipit-source-id: 750e4c39ce88e8d41662f701cf6275d9388ba46a
2019-06-24 20:54:04 -07:00
Maysam Yabandeh
caf0f53a74 Index value delta encoding (#3983)
Summary:
Given that index value is a BlockHandle, which is basically an <offset, size> pair we can apply delta encoding on the values. The first value at each index restart interval encoded the full BlockHandle but the rest encode only the size. Refer to IndexBlockIter::DecodeCurrentValue for the detail of the encoding. This reduces the index size which helps using the  block cache more efficiently. The feature is enabled with using format_version 4.

The feature comes with a bit of cpu overhead which should be paid back by the higher cache hits due to smaller index block size.
Results with sysbench read-only using 4k blocks and using 16 index restart interval:
Format 2:
19585   rocksdb read-only range=100
Format 3:
19569   rocksdb read-only range=100
Format 4:
19352   rocksdb read-only range=100
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3983

Differential Revision: D8361343

Pulled By: maysamyabandeh

fbshipit-source-id: f882ee082322acac32b0072e2bdbb0b5f854e651
2018-08-09 16:58:40 -07:00
Zhongyi Xie
954b496b3f fix memory leak in two_level_iterator
Summary:
this PR fixes a few failed contbuild:
1. ASAN memory leak in Block::NewIterator (table/block.cc:429). the proper destruction of first_level_iter_ and second_level_iter_ of two_level_iterator.cc is missing from the code after the refactoring in https://github.com/facebook/rocksdb/pull/3406
2. various unused param errors introduced by https://github.com/facebook/rocksdb/pull/3662
3. updated comment for `ForceReleaseCachedEntry` to emphasize the use of `force_erase` flag.
Closes https://github.com/facebook/rocksdb/pull/3718

Reviewed By: maysamyabandeh

Differential Revision: D7621192

Pulled By: miasantreble

fbshipit-source-id: 476c94264083a0730ded957c29de7807e4f5b146
2018-04-15 17:26:26 -07:00
Siying Dong
b555ed30a4 Customized BlockBasedTableIterator and LevelIterator
Summary:
Use a customzied BlockBasedTableIterator and LevelIterator to replace current implementations leveraging two-level-iterator. Hope the customized logic will make code easier to understand. As a side effect, BlockBasedTableIterator reduces the allocation for the data block iterator object, and avoid the virtual function call to it, because we can directly reference BlockIter, a final class. Similarly, LevelIterator reduces virtual function call to the dummy iterator iterating the file metadata. It also enabled further optimization.

The upper bound check is also moved from index block to data block. This implementation fits this iterator better. After the change, forwared iterator is slightly optimized to ensure we trim those iterators.

The two-level-iterator now is only used by partitioned index, so it is simplified.
Closes https://github.com/facebook/rocksdb/pull/3406

Differential Revision: D6809041

Pulled By: siying

fbshipit-source-id: 7da3b9b1d3c8e9d9405302c15920af1fcaf50ffa
2018-02-12 17:12:25 -08:00
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
Aaron Gao
a30a696034 do not read next datablock if upperbound is reached
Summary:
Now if we have iterate_upper_bound set, we continue read until get a key >= upper_bound. For a lot of cases that neighboring data blocks have a user key gap between them, our index key will be a user key in the middle to get a shorter size. For example, if we have blocks:
[a b c d][f g h]
Then the index key for the first block will be 'e'.
then if upper bound is any key between 'd' and 'e', for example, d1, d2, ..., d99999999999, we don't have to read the second block and also know that we have done our iteration by reaching the last key that smaller the upper bound already.

This diff can reduce RA in most cases.
Closes https://github.com/facebook/rocksdb/pull/2239

Differential Revision: D4990693

Pulled By: lightmark

fbshipit-source-id: ab30ea2e3c6edf3fddd5efed3c34fcf7739827ff
2017-05-05 23:20:01 -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
sdong
35ad531be3 Seperate InternalIterator from Iterator
Summary:
Separate a new class InternalIterator from class Iterator, when the look-up is done internally, which also means they operate on key with sequence ID and type.

This change will enable potential future optimizations but for now InternalIterator's functions are still the same as Iterator's.
At the same time, separate the cleanup function to a separate class and let both of InternalIterator and Iterator inherit from it.

Test Plan: Run all existing tests.

Reviewers: igor, yhchiang, anthony, kradhakrishnan, IslamAbdelRahman, rven

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48549
2015-10-13 15:32:13 -07:00
sdong
05e2831966 Allocate LevelFileIteratorState and LevelFileNumIterator from DB iterator's arena
Summary: Try to allocate LevelFileIteratorState and LevelFileNumIterator from DB iterator's arena, instead of calling malloc and free.

Test Plan: valgrind check

Reviewers: rven, yhchiang, anthony, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D40929
2015-06-30 17:30:38 -07:00
Igor Canadi
9f7fc3ac45 Turn on -Wshadow
Summary:
...and fix all the errors :)

Jim suggested turning on -Wshadow because it helped him fix number of critical bugs in fbcode. I think it's a good idea to be -Wshadow clean.

Test Plan: compiles

Reviewers: yhchiang, rven, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D27711
2014-10-31 11:59:54 -07:00
sdong
df9069d23f In DB::NewIterator(), try to allocate the whole iterator tree in an arena
Summary:
In this patch, try to allocate the whole iterator tree starting from DBIter from an arena
1. ArenaWrappedDBIter is created when serves as the entry point of an iterator tree, with an arena in it.
2. Add an option to create iterator from arena for following iterators: DBIter, MergingIterator, MemtableIterator, all mem table's iterators, all table reader's iterators and two level iterator.
3. MergeIteratorBuilder is created to incrementally build the tree of internal iterators. It is passed to mem table list and version set and add iterators to it.

Limitations:
(1) Only DB::NewIterator() without tailing uses the arena. Other cases, including readonly DB and compactions are still from malloc
(2) Two level iterator itself is allocated in arena, but not iterators inside it.

Test Plan: make all check

Reviewers: ljin, haobo

Reviewed By: haobo

Subscribers: leveldb, dhruba, yhchiang, igor

Differential Revision: https://reviews.facebook.net/D18513
2014-06-02 17:44:57 -07:00
Lei Jin
ccaca59bee avoid calling FindFile twice in TwoLevelIterator for PlainTable
Summary:
this is to reclaim the regression introduced in
https://reviews.facebook.net/D17853

Test Plan: make all check

Reviewers: igor, haobo, sdong, dhruba, yhchiang

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17985
2014-04-25 12:23:07 -07:00
Lei Jin
d642c60bdc Check PrefixMayMatch on Seek()
Summary:
As a follow-up diff for https://reviews.facebook.net/D17805, add
optimization to check PrefixMayMatch on Seek()

Test Plan: make all check

Reviewers: igor, haobo, sdong, yhchiang, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17853
2014-04-25 12:22:23 -07:00
Siying Dong
d169b67680 [Performance Branch] PlainTable to encode rows with seqID 0, value type using 1 internal byte.
Summary: In PlainTable, use one single byte to represent 8 bytes of internal bytes, if seqID = 0 and it is value type (which should be common for bottom most files). It is to save 7 bytes for uncompressed cases.

Test Plan: make all check

Reviewers: haobo, dhruba, kailiu

Reviewed By: haobo

CC: igor, leveldb

Differential Revision: https://reviews.facebook.net/D15489
2014-02-03 12:19:30 -08:00
Dhruba Borthakur
9cd221094c Add appropriate LICENSE and Copyright message.
Summary:
Add appropriate LICENSE and Copyright message.

Test Plan:
make check

Reviewers:

CC:

Task ID: #

Blame Rev:
2013-10-16 17:48:41 -07:00
Dhruba Borthakur
4463b11cad Migrate names of properties from 'leveldb' prefix to 'rocksdb' prefix.
Summary: Migrate names of properties from 'leveldb' prefix to 'rocksdb' prefix.

Test Plan: make check

Reviewers: emayanke, haobo

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13311
2013-10-06 00:14:26 -07:00
Dhruba Borthakur
a143ef9b38 Change namespace from leveldb to rocksdb
Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.

Test Plan: compile rocksdb

Reviewers: emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13287
2013-10-04 11:59:26 -07:00
Dhruba Borthakur
1186192ed1 Replace include/leveldb with include/rocksdb.
Summary: Replace include/leveldb with include/rocksdb.

Test Plan:
make clean; make check
make clean; make release

Differential Revision: https://reviews.facebook.net/D12489
2013-08-23 10:51:00 -07:00
Haobo Xu
ab8d2f6ab2 [RocksDB] [Performance] Allow different posix advice to be applied to the same table file
Summary:
Current posix advice implementation ties up the access pattern hint with the creation of a file.
It is not possible to apply different advice for different access (random get vs compaction read),
without keeping two open files for the same table. This patch extended the RandomeAccessFile interface
to accept new access hint at anytime. Particularly, we are able to set different access hint on the same
table file based on when/how the file is used.
Two options are added to set the access hint, after the file is first opened and after the file is being
compacted.

Test Plan: make check; db_stress; db_bench

Reviewers: dhruba

Reviewed By: dhruba

CC: MarkCallaghan, leveldb

Differential Revision: https://reviews.facebook.net/D10905
2013-05-30 19:08:44 -07:00
Dhruba Borthakur
ad96563b79 Ability to configure bufferedio-reads, filesystem-readaheads and mmap-read-write per database.
Summary:
This patch allows an application to specify whether to use bufferedio,
reads-via-mmaps and writes-via-mmaps per database. Earlier, there
was a global static variable that was used to configure this functionality.

The default setting remains the same (and is backward compatible):
 1. use bufferedio
 2. do not use mmaps for reads
 3. use mmap for writes
 4. use readaheads for reads needed for compaction

I also added a parameter to db_bench to be able to explicitly specify
whether to do readaheads for compactions or not.

Test Plan: make check

Reviewers: sheki, heyongqiang, MarkCallaghan

Reviewed By: sheki

CC: leveldb

Differential Revision: https://reviews.facebook.net/D9429
2013-03-20 23:14:03 -07:00
Hans Wennborg
36a5f8ed7f A number of fixes:
- Replace raw slice comparison with a call to user comparator.
  Added test for custom comparators.

- Fix end of namespace comments.

- Fixed bug in picking inputs for a level-0 compaction.

  When finding overlapping files, the covered range may expand
  as files are added to the input set.  We now correctly expand
  the range when this happens instead of continuing to use the
  old range.  For example, suppose L0 contains files with the
  following ranges:

      F1: a .. d
      F2:    c .. g
      F3:       f .. j

  and the initial compaction target is F3.  We used to search
  for range f..j which yielded {F2,F3}.  However we now expand
  the range as soon as another file is added.  In this case,
  when F2 is added, we expand the range to c..j and restart the
  search.  That picks up file F1 as well.

  This change fixes a bug related to deleted keys showing up
  incorrectly after a compaction as described in Issue 44.

(Sync with upstream @25072954)
2011-10-31 17:22:06 +00:00
dgrogan@chromium.org
69c6d38342 reverting disastrous MOE commit, returning to r21
git-svn-id: https://leveldb.googlecode.com/svn/trunk@23 62dab493-f737-651d-591e-8d6aee1b9529
2011-04-19 23:11:15 +00:00
dgrogan@chromium.org
b743906eea Revision created by MOE tool push_codebase.
MOE_MIGRATION=


git-svn-id: https://leveldb.googlecode.com/svn/trunk@22 62dab493-f737-651d-591e-8d6aee1b9529
2011-04-19 23:01:25 +00:00
dgrogan@chromium.org
b409afe968 chmod a-x
git-svn-id: https://leveldb.googlecode.com/svn/trunk@21 62dab493-f737-651d-591e-8d6aee1b9529
2011-04-18 23:15:58 +00:00
dgrogan@chromium.org
f779e7a5d8 @20602303. Default file permission is now 755.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@20 62dab493-f737-651d-591e-8d6aee1b9529
2011-04-12 19:38:58 +00:00
jorlow@chromium.org
4671a695fc Move include files into a leveldb subdir.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@18 62dab493-f737-651d-591e-8d6aee1b9529
2011-03-30 18:35:40 +00:00
jorlow@chromium.org
f67e15e50f Initial checkin.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@2 62dab493-f737-651d-591e-8d6aee1b9529
2011-03-18 22:37:00 +00:00