Summary:
Added rate limiter and read rate-limiting support to SequentialFileReader. I've updated call sites to SequentialFileReader::Read with appropriate IO priority (or left a TODO and specified IO_TOTAL for now).
The PR is separated into four commits: the first one added the rate-limiting support, but with some fixes in the unit test since the number of request bytes from rate limiter in SequentialFileReader are not accurate (there is overcharge at EOF). The second commit fixed this by allowing SequentialFileReader to check file size and determine how many bytes are left in the file to read. The third commit added benchmark related code. The fourth commit moved the logic of using file size to avoid overcharging the rate limiter into backup engine (the main user of SequentialFileReader).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9973
Test Plan:
- `make check`, backup_engine_test covers usage of SequentialFileReader with rate limiter.
- Run db_bench to check if rate limiting is throttling as expected: Verified that reads and writes are together throttled at 2MB/s, and at 0.2MB chunks that are 100ms apart.
- Set up: `./db_bench --benchmarks=fillrandom -db=/dev/shm/test_rocksdb`
- Benchmark:
```
strace -ttfe read,write ./db_bench --benchmarks=backup -db=/dev/shm/test_rocksdb --backup_rate_limit=2097152 --use_existing_db
strace -ttfe read,write ./db_bench --benchmarks=restore -db=/dev/shm/test_rocksdb --restore_rate_limit=2097152 --use_existing_db
```
- db bench on backup and restore to ensure no performance regression.
- backup (avg over 50 runs): pre-change: 1.90443e+06 micros/op; post-change: 1.8993e+06 micros/op (improve by 0.2%)
- restore (avg over 50 runs): pre-change: 1.79105e+06 micros/op; post-change: 1.78192e+06 micros/op (improve by 0.5%)
```
# Set up
./db_bench --benchmarks=fillrandom -db=/tmp/test_rocksdb -num=10000000
# benchmark
TEST_TMPDIR=/tmp/test_rocksdb
NUM_RUN=50
for ((j=0;j<$NUM_RUN;j++))
do
./db_bench -db=$TEST_TMPDIR -num=10000000 -benchmarks=backup -use_existing_db | egrep 'backup'
# Restore
#./db_bench -db=$TEST_TMPDIR -num=10000000 -benchmarks=restore -use_existing_db
done > rate_limit.txt && awk -v NUM_RUN=$NUM_RUN '{sum+=$3;sum_sqrt+=$3^2}END{print sum/NUM_RUN, sqrt(sum_sqrt/NUM_RUN-(sum/NUM_RUN)^2)}' rate_limit.txt >> rate_limit_2.txt
```
Reviewed By: hx235
Differential Revision: D36327418
Pulled By: cbi42
fbshipit-source-id: e75d4307cff815945482df5ba630c1e88d064691
Summary:
**Context/Summary:**
The logic related to PositionedRead in SequentialFileReader::Read confused me a bit as discussed here https://github.com/facebook/rocksdb/pull/9973#discussion_r872869256. Therefore I added a drawing with help from cbi42.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10002
Test Plan: - no code change
Reviewed By: anand1976, cbi42
Differential Revision: D36422632
Pulled By: hx235
fbshipit-source-id: 9a8311d2365564f90d216c430f542fc11b2d9cde
Summary:
This change adds File IO Notifications to the SequentialFileReader The SequentialFileReader is extended
with a listener parameter.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8982
Test Plan:
A new test EventListenerTest::OnWALOperationTest has been added. The
test verifies that during restore the sequential file reader is called
and the notifications are fired.
Reviewed By: riversand963
Differential Revision: D31320844
Pulled By: shrfb
fbshipit-source-id: 040b24da7c010d7c14ebb5c6460fae9a19b8c168
Summary:
Add a paranoid check where in case FileSystem layer doesn't fill the buffer but returns succeed, checksum is unlikely to match even if buffer contains a previous block. The byte modified is not useful anyway, so it isn't expect to change any behavior.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8955
Test Plan: See existing CI to pass.
Reviewed By: pdillinger
Differential Revision: D31183966
fbshipit-source-id: dcc4de429e18131873f783b90d3be55d7eb44a1f
Summary:
In order to populate the IOStatus up to the higher level, replace some of the Status to IOStatus.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8820
Test Plan: make check
Reviewed By: pdillinger
Differential Revision: D30967215
Pulled By: zhichao-cao
fbshipit-source-id: ccf9d5cfbd9d3de047c464aaa85f9fa43b474903
Summary:
Removed the uses of the Legacy FileWrapper classes from the source code. The wrappers were creating an additional layer of indirection/wrapping, as the Env already has a FileSystem.
Moved the Custom FileWrapper classes into the CustomEnv, as these classes are really for the private use the the CustomEnv class.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7851
Reviewed By: anand1976
Differential Revision: D26114816
Pulled By: mrambacher
fbshipit-source-id: db32840e58d969d3a0fa6c25aaf13d6dcdc74150
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
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.
This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.
The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.
This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.
The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761
Differential Revision: D18868376
Pulled By: anand1976
fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
Summary:
Unity build fails because of name conflict of IsFileSectorAligned() after recent refactoring. Consolidate the function.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5812
Test Plan: make unity. At least the failure goes away. Also "make all", "make release" and see no regression in normal cases.
Differential Revision: D17411403
fbshipit-source-id: 09d5653471ae2c3a4d898e120a024f7dd08d9c9d
Summary:
file_reader_writer.h and .cc contain several files and helper function, and it's hard to navigate. Separate it to multiple files and put them under file/
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5803
Test Plan: Build whole project using make and cmake.
Differential Revision: D17374550
fbshipit-source-id: 10efca907721e7a78ed25bbf74dc5410dea05987
Changyu Bi