Commit Graph

5 Commits

Author SHA1 Message Date
Yanqin Jin
82b3888433 Enable backward iterator for keys with user-defined timestamp (#8035)
Summary:
This PR does the following:

- Enable backward iteration for keys with user-defined timestamp. Note that merge, single delete, range delete are not supported yet.
- Introduces a new helper API `Comparator::EqualWithoutTimestamp()`.
- Fix a typo in `SetTimestamp()`.
- Add/update unit tests

Run db_bench (built with DEBUG_LEVEL=0) to demonstrate that no overhead is introduced for CPU-intensive workloads with a lot of `Prev()`. Also provided results of iterating keys with timestamps.

1. Disable timestamp, run:
```
./db_bench -db=/dev/shm/rocksdb -disable_wal=1 -benchmarks=fillseq,seekrandom[-W1-X6] -reverse_iterator=1 -seek_nexts=5
```
Results:
> Baseline
> - seekrandom [AVG    6 runs] : 96115 ops/sec;   53.2 MB/sec
> - seekrandom [MEDIAN 6 runs] : 98075 ops/sec;   54.2 MB/sec
>
> This PR
> - seekrandom [AVG    6 runs] : 95521 ops/sec;   52.8 MB/sec
> - seekrandom [MEDIAN 6 runs] : 96338 ops/sec;   53.3 MB/sec

2. Enable timestamp, run:
```
./db_bench -user_timestamp_size=8  -db=/dev/shm/rocksdb -disable_wal=1 -benchmarks=fillseq,seekrandom[-W1-X6] -reverse_iterator=1 -seek_nexts=5
```
Result:
> Baseline: not supported
>
> This PR
> - seekrandom [AVG    6 runs] : 90514 ops/sec;   50.1 MB/sec
> - seekrandom [MEDIAN 6 runs] : 90834 ops/sec;   50.2 MB/sec

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8035

Reviewed By: ltamasi

Differential Revision: D26926668

Pulled By: riversand963

fbshipit-source-id: 95330cc2242397c03e09d29e5417dfb0adc98ef5
2021-03-10 11:15:46 -08:00
Andrew Kryczka
dd29ad4223 Separate internal and user key comparators in BlockIter (#6944)
Summary:
Replace `BlockIter::comparator_` and `IndexBlockIter::user_comparator_wrapper_` with a concrete `UserComparatorWrapper` and `InternalKeyComparator`. The motivation for this change was the inconvenience of not knowing the concrete type of `BlockIter::comparator_`, which prevented calling specialized internal key comparison functions to optimize comparison of keys with global seqno applied.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6944

Test Plan:
benchmark setup -- single file DBs, in-memory, no compression. "normal_db"
created by regular flush; "ingestion_db" created by ingesting a file. Both
DBs have same contents.

```
$ TEST_TMPDIR=/dev/shm/normal_db/ ./db_bench -benchmarks=fillrandom,compact -write_buffer_size=10485760000 -disable_auto_compactions=true -compression_type=none -num=1000000
$ ./ldb write_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ --compression_type=no --hex --create_if_missing < <(./sst_dump --command=scan --output_hex --file=/dev/shm/normal_db/dbbench/000007.sst | awk 'began {print "0x" substr($1, 2, length($1) - 2), "==>", "0x" $5} ; /^Sst file format: block-based/ {began=1}')
$ ./ldb ingest_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/
```

benchmark run command:

```
$ TEST_TMPDIR=/dev/shm/$DB/ ./db_bench -benchmarks=seekrandom -seek_nexts=$SEEK_NEXT -use_existing_db=true -cache_index_and_filter_blocks=false -num=1000000 -cache_size=0 -threads=1 -reads=200000000 -mmap_read=1 -verify_checksum=false
```

results: perf improved marginally for ingestion_db and did not change significantly for normal_db:

SEEK_NEXT | DB | code | ops/sec | % change
-- | -- | -- | -- | --
0 | normal_db | master | 350880 |  
0 | normal_db | PR6944 | 351040 | 0.0
0 | ingestion_db | master | 343255 |  
0 | ingestion_db | PR6944 | 349424 | 1.8
10 | normal_db | master | 218711 |  
10 | normal_db | PR6944 | 217892 | -0.4
10 | ingestion_db | master | 220334 |  
10 | ingestion_db | PR6944 | 226437 | 2.8

Reviewed By: pdillinger

Differential Revision: D21924676

Pulled By: ajkr

fbshipit-source-id: ea4288a2eefa8112eb6c651a671c1de18c12e538
2020-07-07 17:26:16 -07:00
Yanqin Jin
d93812c9ae Iterator with timestamp (#6255)
Summary:
Preliminary support for iterator with user timestamp. Current implementation does not consider merge operator and reverse iterator. Auto compaction is also disabled in unit tests.

Create an iterator with timestamp.
```
...
read_opts.timestamp = &ts;
auto* iter = db->NewIterator(read_opts);
// target is key without timestamp.
for (iter->Seek(target); iter->Valid(); iter->Next()) {}
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {}
delete iter;
read_opts.timestamp = &ts1;
// lower_bound and upper_bound are without timestamp.
read_opts.iterate_lower_bound = &lower_bound;
read_opts.iterate_upper_bound = &upper_bound;
auto* iter1 = db->NewIterator(read_opts);
// Do Seek or SeekToFirst()
delete iter1;
```

Test plan (dev server)
```
$make check
```

Simple benchmarking (dev server)
1. The overhead introduced by this PR even when timestamp is disabled.
key size: 16 bytes
value size: 100 bytes
Entries: 1000000
Data reside in main memory, and try to stress iterator.
Repeated three times on master and this PR.
- Seek without next
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3
```
master: 159047.0 ops/sec
this PR: 158922.3 ops/sec (2% drop in throughput)
- Seek and next 10 times
```
./db_bench -db=/dev/shm/rocksdbtest-1000 -benchmarks=fillseq,seekrandom -enable_pipelined_write=false -disable_wal=true -format_version=3 -seek_nexts=10
```
master: 109539.3 ops/sec
this PR: 107519.7 ops/sec (2% drop in throughput)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6255

Differential Revision: D19438227

Pulled By: riversand963

fbshipit-source-id: b66b4979486f8474619f4aa6bdd88598870b0746
2020-03-06 16:24:27 -08:00
sdong
fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00
Yi Wu
d69241586e Fix perf_context.user_key_comparison_count for range scan (#5098)
Summary:
Currently `perf_context.user_key_comparison_count` is bump only in `InternalKeyComparator`. For places user comparator is used directly the counter is not bump. Fixing the majority of it.

Index iterator and filter code also use user comparator directly and don't bump the counter. It is not fixed in this patch.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5098

Differential Revision: D14603753

Pulled By: siying

fbshipit-source-id: 1cd41035644ca9e49b97a51030a5d1e15f5f3cae
2019-03-27 10:34:27 -07:00