Summary:
Right, when reading from option files, no readahead is used and 8KB buffer is used. It might introduce high latency if the file system provide high latency and doesn't do readahead. Instead, introduce a readahead to the file. When calling inside DB, infer the value from options.log_readahead. Otherwise, a default 512KB readahead size is used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6372
Test Plan: Add --log_readahead_size in db_bench. Run it with several options and observe read size from option files using strace.
Differential Revision: D19727739
fbshipit-source-id: e6d8053b0a64259abc087f1f388b9cd66fa8a583
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:
util/ means for lower level libraries, so it's a good idea to move the files which requires knowledge to DB out. Create a file/ and move some files there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5375
Differential Revision: D15550935
Pulled By: siying
fbshipit-source-id: 61a9715dcde5386eebfb43e93f847bba1ae0d3f2
Summary:
[RocksDB] Make it easier for users to load options from option file and set shared block cache.
Right now, it requires several dynamic casting for users to set the shared block cache to their option struct cast from the option file.
If people don't do that, every CF of every DB will generate its own 8MB block cache. It's not a usable setting. So we are dragging every user who loads options from the file into such a mess.
Instead, we should allow them to pass their cache object to LoadLatestOptions() and LoadOptionsFromFile(), so that those loaded option structs will have the shared block cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5063
Differential Revision: D14518584
Pulled By: rashmishrm
fbshipit-source-id: c91430ff9425a0e67d76fc67931d755f491ca5aa
Summary:
Added a flag, `ignore_unknown_options`, to skip unknown options when loading an options file (using `LoadLatestOptions`/`LoadOptionsFromFile`) or while verifying options (using `CheckOptionsCompatibility`). This will help in downgrading the db to an older version.
Also added `--ignore_unknown_options` flag to ldb
**Example Use case:**
In MyRocks, if copying from newer version to older version, it is often impossible to start because of new RocksDB options that don't exist in older version, even though data format is compatible.
MyRocks uses these load and verify functions in [ha_rocksdb.cc::check_rocksdb_options_compatibility](e004fd9f41/storage/rocksdb/ha_rocksdb.cc (L3348-L3401)).
**Test Plan:**
Updated the unit tests.
`make check`
ldb:
$ ./ldb --db=/tmp/test_db --create_if_missing put a1 b1
OK
Now edit /tmp/test_db/<OPTIONS-file> and add an unknown option.
Try loading the options now, and it fails:
$ ./ldb --db=/tmp/test_db --try_load_options get a1
Failed: Invalid argument: Unrecognized option DBOptions:: abcd
Passes with the new --ignore_unknown_options flag
$ ./ldb --db=/tmp/test_db --try_load_options --ignore_unknown_options get a1
b1
Closes https://github.com/facebook/rocksdb/pull/2423
Differential Revision: D5212091
Pulled By: sagar0
fbshipit-source-id: 2ec17636feb47dc0351b53a77e5f15ef7cbf2ca7
Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090
Differential Revision: D4833681
Pulled By: siying
fbshipit-source-id: 2fd8bef
Summary:
It is confusing to have auto_roll_logger to stay under db/, which has nothing to do with database. Move filename together as it is a dependency.
Closes https://github.com/facebook/rocksdb/pull/2080
Differential Revision: D4821141
Pulled By: siying
fbshipit-source-id: ca7d768
Summary:
Add CheckOptionsCompatibility() API to options_util that returns
Status::OK if the input DBOptions and ColumnFamilyDescriptors
are compatible with the latest options stored in the specified DB path.
Test Plan: Added tests in options_util_test
Reviewers: igor, anthony, IslamAbdelRahman, rven, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D50649
Summary:
This patch adds OptionsUtil::LoadOptionsFromFile() and
OptionsUtil::LoadLatestOptionsFromDB(), which allow developers
to construct DBOptions and ColumnFamilyOptions from a RocksDB
options file. Note that most pointer-typed options such as
merge_operator will not be constructed.
With this API, developers no longer need to remember all the
options in order to reopen an existing rocksdb instance like
the following:
DBOptions db_options;
std::vector<std::string> cf_names;
std::vector<ColumnFamilyOptions> cf_opts;
// Load primitive-typed options from an existing DB
OptionsUtil::LoadLatestOptionsFromDB(
dbname, &db_options, &cf_names, &cf_opts);
// Initialize necessary pointer-typed options
cf_opts[0].merge_operator.reset(new MyMergeOperator());
...
// Construct the vector of ColumnFamilyDescriptor
std::vector<ColumnFamilyDescriptor> cf_descs;
for (size_t i = 0; i < cf_opts.size(); ++i) {
cf_descs.emplace_back(cf_names[i], cf_opts[i]);
}
// Open the DB
DB* db = nullptr;
std::vector<ColumnFamilyHandle*> cf_handles;
auto s = DB::Open(db_options, dbname, cf_descs,
&handles, &db);
Test Plan:
Augment existing tests in column_family_test
options_test
db_test
Reviewers: igor, IslamAbdelRahman, sdong, anthony
Reviewed By: anthony
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D49095
sdong