Commit Graph

15 Commits

Author SHA1 Message Date
Venkatesh Radhakrishnan
7824444bfc Reuse file iterators in tailing iterator when memtable is flushed
Summary:
Under a tailing workload, there were increased block cache
misses when a memtable was flushed because we were rebuilding iterators
in that case since the version set changed. This was exacerbated in the
case of iterate_upper_bound, since file iterators which were over the
iterate_upper_bound would have been deleted and are now brought back as
part of the Rebuild, only to be deleted again. We now renew the iterators
and only build iterators for files which are added and delete file
iterators for files which are deleted.
Refer to https://reviews.facebook.net/D50463 for previous version

Test Plan: DBTestTailingIterator.TailingIteratorTrimSeekToNext

Reviewers: anthony, IslamAbdelRahman, igor, tnovak, yhchiang, sdong

Reviewed By: sdong

Subscribers: yhchiang, march, dhruba, leveldb, lovro

Differential Revision: https://reviews.facebook.net/D50679
2015-11-13 15:50:59 -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
Venkatesh Radhakrishnan
91f3c90792 Fix case when forward iterator misses a new update
Summary:
This diff fixes a case when the forward iterator misses a new
insert when the mutable iterator is not current. The test is also
improved and the check for deleted iterators is made more informative.

Test Plan: DBTailingIteratorTest.*Trim

Reviewers: tnovak, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D46167
2015-09-04 14:28:45 -07:00
Tomislav Novak
5508122ed6 Fix a perf regression in ForwardIterator
Summary:
I noticed that memtable iterator usually crosses the `iterate_upper_bound`
threshold when tailing. Changes introduced in D43833 made `NeedToSeekImmutable`
always return true in such case, even when `Seek()` only needs to rewind the
memtable iterator. In a test I ran, this caused the "tailing efficiency"
(ratio of calls to `Seek()` that only affect the memtable versus all seeks)
to drop almost to zero.

This diff attempts to fix the regression by using a different flag to indicate
that `current_` is over the limit instead of resetting `valid_` in
`UpdateCurrent()`.

Test Plan: `DBTestTailingIterator.TailingIteratorUpperBound`

Reviewers: sdong, rven

Reviewed By: rven

Subscribers: dhruba, march

Differential Revision: https://reviews.facebook.net/D45909
2015-09-01 09:54:30 -07:00
Venkatesh Radhakrishnan
4d28a7d8ab Add a whitebox test for deleted file iterators.
Summary:
We have earlier added a feature to delete file iterators when the
current key is over the iterate upper bound. We now add a whitebox test
to check if the file iterators were actually deleted.

Test Plan: Add check for a range which has deleted iterators.

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45321
2015-08-25 13:40:58 -07:00
Andres Noetzli
b604d2562f Removing unused variables to fix build
Summary: Removing two unused variables that prevented compilation.

Test Plan: make all

Reviewers: rven, sdong, yhchiang, anthony, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D44991
2015-08-19 16:57:40 -07:00
Venkatesh Radhakrishnan
1b114eed4d Free file iterators for files which are above the iterate upper bound to Improve memory utilization
Summary:
This diff improves the memory utilization for tailing iterators RocksDB,
by freeing file iterators which are over the upper bound.
It is an updating on Siying's original diff for improving the memory usage for
tailing iterators. The changes for the seek and next path are now complete
and a test has been added to exercise these paths while deleting file iterators
which are above the upper bound.

Test Plan: db_tailing_iter_test.TailingIteratorTrimSeekToNext

Reviewers: march, tnovak, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D43833
2015-08-19 16:05:51 -07:00
Igor Sugak
62247ffa3b rocksdb: Add missing override
Summary:
When using latest clang (3.6 or 3.7/trunck) rocksdb is failing with many errors. Almost all of them are missing override errors. This diff adds missing override keyword. No manual changes.

Prerequisites: bear and clang 3.5 build with extra tools

```lang=bash
% USE_CLANG=1 bear make all # generate a compilation database http://clang.llvm.org/docs/JSONCompilationDatabase.html
% clang-modernize -p . -include . -add-override
% make format
```

Test Plan:
Make sure all tests are passing.
```lang=bash
% #Use default fb code clang.
% make check
```
Verify less error and no missing override errors.
```lang=bash
% # Have trunk clang present in path.
% ROCKSDB_NO_FBCODE=1 CC=clang CXX=clang++ make
```

Reviewers: igor, kradhakrishnan, rven, meyering, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D34077
2015-02-26 11:28:41 -08:00
Tomislav Novak
35c8c814e8 Make ForwardIterator::status() more efficient
Summary:
In D19581 I made `ForwardIterator::status()` check all child iterators,
including immutable ones. It's, however, not necessary to do it every
time -- it'll suffice to check only when they're used and their status
could change.

This diff:
* introduces `immutable_status_` which is updated by `Seek()` and `Next()`
* removes special handling of `kIncomplete` status in those methods

Test Plan:
* `db_test`
* hacked ReadSequential in db_bench.cc to check `status()` in addition to
  validity:

```
   $ ./db_bench -use_existing_db -benchmarks readseq -disable_auto_compactions \
      -use_tailing_iterator  # without this patch
   Keys:       16 bytes each
   Values:     100 bytes each (50 bytes after compression)
   Entries:    1000000
   [...]
   DB path: [/dev/shm/rocksdbtest/dbbench]
   readseq      :       0.562 micros/op 1778103 ops/sec;   98.4 MB/s
   $ ./db_bench -use_existing_db -benchmarks readseq -disable_auto_compactions \
      -use_tailing_iterator  # with the patch
   readseq      :       0.433 micros/op 2311363 ops/sec;  127.8 MB/s
```

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb, march, lovro

Differential Revision: https://reviews.facebook.net/D24063
2014-11-10 15:44:20 -08:00
Lei Jin
574028679b dynamic max_sequential_skip_in_iterations
Summary:
This is not a critical options. Making it dynamic so that we can remove
more reference to cfd->options()

Test Plan: unit test

Reviewers: yhchiang, sdong, igor

Reviewed By: igor

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D24957
2014-10-23 15:34:21 -07:00
Tomislav Novak
187b29938c ForwardIterator: update prev_key_ only if prefix hasn't changed
Summary:
Since ForwardIterator is on a level below DBIter, the latter may call Next() on
it (e.g. in order to skip deletion markers). Since this also updates
`prev_key_`, it may prevent the Seek() optimization.

For example, assume that there's only one SST file and it contains the following
entries: 0101, 0201 (`ValueType::kTypeDeletion`, i.e. a tombstone record), 0201
(`kTypeValue`), 0202. Memtable is empty. `Seek(0102)` will result in `prev_key_`
being set to `0201` instead of `0102`, since `DBIter::Seek()` will call
`ForwardIterator::Next()` to skip record 0201. Therefore, when `Seek(0102)` is
called again, `NeedToSeekImmutable()` will return true.

This fix relies on `prefix_extractor_` to detect prefix changes. `prev_key_` is
only set to `current_->key()` as long as they have the same prefix.

I also made a small change to `NeedToSeekImmutable()` so it no longer returns
true when the db is empty (i.e. there's nothing but a memtable).

Test Plan:
   $ TEST_TMPDIR=/dev/shm/rocksdbtest ROCKSDB_TESTS=TailingIterator ./db_test

Reviewers: sdong, igor, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D23823
2014-10-01 17:10:48 -07:00
Stanislau Hlebik
45a5e3ede0 Remove path with arena==nullptr from NewInternalIterator
Summary:
Simply code by removing code path which does not use Arena
from NewInternalIterator

Test Plan:
make all check
make valgrind_check

Reviewers: sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D22395
2014-09-04 17:40:41 -07:00
Tomislav Novak
0f9c43ea36 ForwardIterator: reset incomplete iterators on Seek()
Summary:
When reading from kBlockCacheTier, ForwardIterator's internal child iterators
may end up in the incomplete state (read was unable to complete without doing
disk I/O). `ForwardIterator::status()` will correctly report that; however, the
iterator may be stuck in that state until all sub-iterators are rebuilt:

  * `NeedToSeekImmutable()` may return false even if some sub-iterators are
    incomplete
  * one of the child iterators may be an empty iterator without any state other
    that the kIncomplete status (created using `NewErrorIterator()`); seeking on
    any such iterator has no effect -- we need to construct it again

Akin to rebuilding iterators after a superversion bump, this diff makes forward
iterator reset all incomplete child iterators when `Seek()` or `Next()` are
called.

Test Plan: TEST_TMPDIR=/dev/shm/rocksdbtest ROCKSDB_TESTS=TailingIterator ./db_test

Reviewers: igor, sdong, ljin

Reviewed By: ljin

Subscribers: lovro, march, leveldb

Differential Revision: https://reviews.facebook.net/D22575
2014-08-29 16:21:29 -07:00
Igor Canadi
fd27001072 Fix compile errors on Mac
Summary: https://phabricator.fb.com/P11372644

Test Plan: compiles

Reviewers: sdong, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18873
2014-06-03 12:28:58 -07:00
Lei Jin
388d2054c7 forward iterator
Summary:
Forward iterator puts everything together in a flat structure instead of
a hierarchy of nested iterators. this should simplify the code and
provide better performance. It also enables more optimization since all
information are accessiable in one place.
Init evaluation shows about 6% improvement

Test Plan: db_test and db_bench

Reviewers: dhruba, igor, tnovak, sdong, haobo

Reviewed By: haobo

Subscribers: sdong, leveldb

Differential Revision: https://reviews.facebook.net/D18795
2014-05-30 14:31:55 -07:00