Summary:
The new `MultiGetEntity` API can be used to get a consistent view of
a batch of keys, with the results presented as wide-column entities.
Similarly to `GetEntity` and the iterator's `columns` API, if the entry
corresponding to the key is a wide-column entity to start with, it is
returned as-is, and if it is a plain key-value, it is wrapped into an entity
with a single default column.
Implementation-wise, the new API shares the logic of the batched `MultiGet`
API (via the `MultiGetCommon` methods). Both single-CF and multi-CF
`MultiGetEntity` APIs are provided, and blobs are also supported.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11222
Test Plan: `make check`
Reviewed By: akankshamahajan15
Differential Revision: D43256950
Pulled By: ltamasi
fbshipit-source-id: 47fb2cb7e2d0470e3580f43fdb2fe9e51f0e7005
Summary:
The patch fixes a feature interaction bug between BlobDB and the `GetEntity` API:
without the patch, `GetEntity` would return the blob reference (wrapped into a
single-column entity) instead of the actual blob value.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11162
Test Plan: `make check`
Reviewed By: akankshamahajan15
Differential Revision: D42854092
Pulled By: ltamasi
fbshipit-source-id: f750d0ff57def107da16f545077ddce9860ff21a
Summary:
Use the user key on sst file for blob verification for `Get` and `MultiGet` instead of the user key passed from caller.
Add tests for `Get` and `MultiGet` operations when user defined timestamp feature is enabled in a BlobDB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11105
Test Plan:
make V=1 db_blob_basic_test
./db_blob_basic_test --gtest_filter="DBBlobTestWithTimestamp.*"
Reviewed By: ltamasi
Differential Revision: D42716487
Pulled By: jowlyzhang
fbshipit-source-id: 5987ecbb7e56ddf46d2467a3649369390789506a
Summary:
We haven't been actively mantaining RocksDB LITE recently and the size must have been gone up significantly. We are removing the support.
Most of changes were done through following comments:
unifdef -m -UROCKSDB_LITE `git grep -l ROCKSDB_LITE | egrep '[.](cc|h)'`
by Peter Dillinger. Others changes were manually applied to build scripts, CircleCI manifests, ROCKSDB_LITE is used in an expression and file db_stress_test_base.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11147
Test Plan: See CI
Reviewed By: pdillinger
Differential Revision: D42796341
fbshipit-source-id: 4920e15fc2060c2cd2221330a6d0e5e65d4b7fe2
Summary:
Apply the formatting changes suggested by `clang-format`, except
where they would ruin the ASCII art in `blob_log_format.h`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10856
Test Plan: `make check`
Reviewed By: siying
Differential Revision: D40652224
Pulled By: ltamasi
fbshipit-source-id: 8c1f5757b758474ea3e8102a7c5a1cf9e6dc1402
Summary:
**Summary:**
When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache.
When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache.
**Implementation Details**
Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true)
The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache:
1. If a handle is found in primary cache:
1.1. If the handle's value is not nullptr, it is returned immediately.
1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache.
- 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
- 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache.
2. If a handle is not found in primary cache:
2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle.
The behaviors of `LRUCacheShard::Promote()` are updated as follows:
1. If `e->sec_handle` has value, one of the following steps can happen:
1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle.
1.2. Insert the item into the primary cache and return the handle to caller.
1.3. Exception handling.
3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released.
The behavior of `CompressedSecondaryCache::Insert()` is updated:
1. If a block is evicted from the primary cache for the first time, a dummy item is inserted.
4. If a dummy item is found for a block, the block is inserted into the secondary cache.
The behavior of `CompressedSecondaryCache:::Lookup()` is updated:
1. If a handle is not found or it is a dummy item, a nullptr is returned.
2. If `erase_handle` is true, the handle is erased.
The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527
Test Plan:
1. stress tests.
5. unit tests.
6. CPU profiling for db_bench.
Reviewed By: siying
Differential Revision: D38747613
Pulled By: gitbw95
fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
Summary:
Example failure:
```
db/blob/db_blob_basic_test.cc:226: Failure
Expected equality of these values:
i
Which is: 1
num_blobs
Which is: 5
```
I can't repro locally, but it looks like the 2KB cache is too small to guarantee no eviction happens between loading all the data into cache and reading from `kBlockCacheTier`. This 2KB setting appears to have come from a test where the cached entries are pinned, where it makes sense to have a small setting. However, such a small setting makes less sense when the blocks are evictable but must remain cached per the test's expectation. This PR increases the capacity setting to 2MB for those cases.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10636
Reviewed By: cbi42
Differential Revision: D39250976
Pulled By: ajkr
fbshipit-source-id: 769309f9a19cfac20b67b927805c8df5c1d2d1f5
Summary:
We have recently added caching support to BlobDB, and separately,
implemented an optimization where reading blobs from the cache
results in the cache handle being transferred to the target `PinnableSlice`
(as opposed to the contents getting copied). With these changes,
it makes sense to reset the `PinnableSlice` storing the blob value in
`DBIter` as soon as we move to a different iterator position to prevent
us from holding on to the cache handle any longer than necessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10490
Test Plan: `make check`
Reviewed By: akankshamahajan15
Differential Revision: D38473630
Pulled By: ltamasi
fbshipit-source-id: 84c045ffac76436c6152fd0f5775b007f4051386
Summary:
Similarly to https://github.com/facebook/rocksdb/pull/10457, we now have
to explicitly set the `fill_cache` read option when reading blobs in
`DBIter` to prevent the cache from getting polluted by queries with
`fill_cache` set to false. (Before we added support for a blob cache,
the setting had not made any difference either way.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10492
Test Plan: `make check`
Reviewed By: akankshamahajan15
Differential Revision: D38476121
Pulled By: ltamasi
fbshipit-source-id: ea5c5e252f83e4a4e2c74156b37d40308d7e0c80
Summary:
Many workloads have temporal locality, where recently written items are read back in a short period of time. When using remote file systems, this is inefficient since it involves network traffic and higher latencies. Because of this, we would like to support prepopulating the blob cache during flush.
This task is a part of https://github.com/facebook/rocksdb/issues/10156
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10298
Reviewed By: ltamasi
Differential Revision: D37908743
Pulled By: gangliao
fbshipit-source-id: 9feaed234bc719d38f0c02975c1ad19fa4bb37d1
Summary:
- [x] Enabled blob caching for MultiGetBlob in RocksDB
- [x] Refactored MultiGetBlob logic and interface in RocksDB
- [x] Cleaned up Version::MultiGetBlob() and moved 'blob'-related code snippets into BlobSource
- [x] Add End-to-end test cases in db_blob_basic_test and also add unit tests in blob_source_test
This task is a part of https://github.com/facebook/rocksdb/issues/10156
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10272
Reviewed By: ltamasi
Differential Revision: D37558112
Pulled By: gangliao
fbshipit-source-id: a73a6a94ffdee0024d5b2a39e6d1c1a7d38664db
Summary:
There is currently no caching mechanism for blobs, which is not ideal especially when the database resides on remote storage (where we cannot rely on the OS page cache). As part of this task, we would like to make it possible for the application to configure a blob cache.
In this task, we formally introduced the blob source to RocksDB. BlobSource is a new abstraction layer that provides universal access to blobs, regardless of whether they are in the blob cache, secondary cache, or (remote) storage. Depending on user settings, it always fetch blobs from multi-tier cache and storage with minimal cost.
Note: The new `MultiGetBlob()` implementation is not included in the current PR. To go faster, we aim to create a separate PR for it in parallel!
This PR is a part of https://github.com/facebook/rocksdb/issues/10156
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10198
Reviewed By: ltamasi
Differential Revision: D37294735
Pulled By: gangliao
fbshipit-source-id: 9cb50422d9dd1bc03798501c2778b6c7520c7a1e
Summary:
In `FileMetaData`, we keep track of the lowest-numbered blob file
referenced by the SST file in question for the purposes of BlobDB's
garbage collection in the `oldest_blob_file_number` field, which is
updated in `UpdateBoundaries`. However, with the current code,
`BlobIndex` decoding errors (or invalid blob file numbers) are swallowed
in this method. The patch changes this by propagating these errors
and failing the corresponding flush/compaction. (Note that since blob
references are generated by the BlobDB code and also parsed by
`CompactionIterator`, in reality this can only happen in the case of
memory corruption.)
This change necessitated updating some unit tests that involved
fake/corrupt `BlobIndex` objects. Some of these just used a dummy string like
`"blob_index"` as a placeholder; these were replaced with real `BlobIndex`es.
Some were relying on the earlier behavior to simulate corruption; these
were replaced with `SyncPoint`-based test code that corrupts a valid
blob reference at read time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9851
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D35683671
Pulled By: ltamasi
fbshipit-source-id: f7387af9945c48e4d5c4cd864f1ba425c7ad51f6
Summary:
This information has been already available as part of the `rocksdb.blob-stats`
string property. The patch adds a dedicated integer property to make it easier
to surface this information in monitoring systems.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9835
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D35619495
Pulled By: ltamasi
fbshipit-source-id: 03fb0b228aa27d3859a1e3783bcb7eca095607f8
Summary:
Extend the periodic statistics in the info log with the total amount of garbage
in blob files and the space amplification pertaining to blob files, where the
latter is defined as `total_blob_file_size / (total_blob_file_size - total_blob_garbage_size)`.
Also expose the space amp via the `rocksdb.blob-stats` DB property.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9538
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D34126855
Pulled By: ltamasi
fbshipit-source-id: 3153e7a0fe0eca440322db273f4deaabaccc51b2
Summary:
Allow compaction_job_test, db_io_failure_test, dbformat_test, deletefile_test, and fault_injection_test to use a custom Env object. Also move ```RegisterCustomObjects``` declaration to a header file to simplify things.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9087
Test Plan: Run manually using "buck test rocksdb/src:compaction_job_test_fbcode" etc.
Reviewed By: riversand963
Differential Revision: D32007222
Pulled By: anand1976
fbshipit-source-id: 99af58559e25bf61563dfa95dc46e31fa7375792
Summary:
`RandomAccessFileReader::MultiRead()` tries to merge requests in direct IO, assuming input IO requests are
sorted by offsets.
Add a test in direct IO mode.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8953
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D31183546
Pulled By: riversand963
fbshipit-source-id: 5d043ec68e2daa47a3149066150afd41ee3d73e6
Summary:
The patch adjusts the definition of BlobDB's DB properties a bit by
switching to `GetBlobFileSize` from `GetTotalBlobBytes`. The
difference is that the value returned by `GetBlobFileSize` includes
the blob file header and footer as well, and thus matches the on-disk
size of blob files. In addition, the patch removes the `Version` number
from the `blob_stats` property, and updates/extends the unit tests a little.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8902
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D30859542
Pulled By: ltamasi
fbshipit-source-id: e3426d2d567bd1bd8c8636abdafaafa0743c854c
Summary:
RocksDB exposes certain internal statistics via the DB property interface.
However, there are currently no properties related to BlobDB.
For starters, we would like to add the following BlobDB properties:
`rocksdb.num-blob-files`: number of blob files in the current Version (kind of like `num-files-at-level` but note this is not per level, since blob files are not part of the LSM tree).
`rocksdb.blob-stats`: this could return the total number and size of all blob files, and potentially also the total amount of garbage (in bytes) in the blob files in the current Version.
`rocksdb.total-blob-file-size`: the total size of all blob files (as a blob counterpart for `total-sst-file-size`) of all Versions.
`rocksdb.live-blob-file-size`: the total size of all blob files in the current Version.
`rocksdb.estimate-live-data-size`: this is actually an existing property that we can extend so it considers blob files as well. When it comes to blobs, we actually have an exact value for live bytes. Namely, live bytes can be computed simply as total bytes minus garbage bytes, summed over the entire set of blob files in the Version.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8734
Test Plan:
```
➜ rocksdb git:(new_feature_blobDB_properties) ./db_blob_basic_test
[==========] Running 16 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 10 tests from DBBlobBasicTest
[ RUN ] DBBlobBasicTest.GetBlob
[ OK ] DBBlobBasicTest.GetBlob (12 ms)
[ RUN ] DBBlobBasicTest.MultiGetBlobs
[ OK ] DBBlobBasicTest.MultiGetBlobs (11 ms)
[ RUN ] DBBlobBasicTest.GetBlob_CorruptIndex
[ OK ] DBBlobBasicTest.GetBlob_CorruptIndex (10 ms)
[ RUN ] DBBlobBasicTest.GetBlob_InlinedTTLIndex
[ OK ] DBBlobBasicTest.GetBlob_InlinedTTLIndex (12 ms)
[ RUN ] DBBlobBasicTest.GetBlob_IndexWithInvalidFileNumber
[ OK ] DBBlobBasicTest.GetBlob_IndexWithInvalidFileNumber (9 ms)
[ RUN ] DBBlobBasicTest.GenerateIOTracing
[ OK ] DBBlobBasicTest.GenerateIOTracing (11 ms)
[ RUN ] DBBlobBasicTest.BestEffortsRecovery_MissingNewestBlobFile
[ OK ] DBBlobBasicTest.BestEffortsRecovery_MissingNewestBlobFile (13 ms)
[ RUN ] DBBlobBasicTest.GetMergeBlobWithPut
[ OK ] DBBlobBasicTest.GetMergeBlobWithPut (11 ms)
[ RUN ] DBBlobBasicTest.MultiGetMergeBlobWithPut
[ OK ] DBBlobBasicTest.MultiGetMergeBlobWithPut (14 ms)
[ RUN ] DBBlobBasicTest.BlobDBProperties
[ OK ] DBBlobBasicTest.BlobDBProperties (21 ms)
[----------] 10 tests from DBBlobBasicTest (124 ms total)
[----------] 6 tests from DBBlobBasicTest/DBBlobBasicIOErrorTest
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/0
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/0 (12 ms)
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/1
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/1 (10 ms)
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/0
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/0 (10 ms)
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/1
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/1 (10 ms)
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/0
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/0 (1011 ms)
[ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/1
[ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/1 (1013 ms)
[----------] 6 tests from DBBlobBasicTest/DBBlobBasicIOErrorTest (2066 ms total)
[----------] Global test environment tear-down
[==========] 16 tests from 2 test cases ran. (2190 ms total)
[ PASSED ] 16 tests.
```
Reviewed By: ltamasi
Differential Revision: D30690849
Pulled By: Zhiyi-Zhang
fbshipit-source-id: a7567319487ad76bd1a2e24bf143afdbbd9e4346
Summary:
The PerThreadDBPath has already specified a slash. It does not need to be specified when initializing the test path.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8555
Reviewed By: ajkr
Differential Revision: D29758399
Pulled By: jay-zhuang
fbshipit-source-id: 6d2b878523e3e8580536e2829cb25489844d9011
Summary:
This PR add support for Merge operation in Integrated BlobDB with base values(i.e DB::Put). Merged values can be retrieved through DB::Get, DB::MultiGet, DB::GetMergeOperands and Iterator operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8292
Test Plan: Add new unit tests
Reviewed By: ltamasi
Differential Revision: D28415896
Pulled By: akankshamahajan15
fbshipit-source-id: e9b3478bef51d2f214fb88c31ed3c8d2f4a531ff
Summary:
If `options.best_efforts_recovery == true`, RocksDB currently tolerates missing table files and recovers to the latest version without missing table files (not considering WAL). It is necessary to handle blob files as well to make the feature more complete.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8180
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D27840556
Pulled By: riversand963
fbshipit-source-id: 041685d0dc2e7779ac4f0374c07a8a327704aa5e
Summary:
Add request_id in IODebugContext which will be populated by
underlying FileSystem for IOTracing purposes. Update IOTracer to trace
request_id in the tracing records. Provided API
IODebugContext::SetRequestId which will set the request_id and enable
tracing for request_id. The API hides the implementation and underlying
file system needs to call this API directly.
Update DB::StartIOTrace API and remove redundant Env* from the
argument as its not used and DB already has Env that is passed down to
IOTracer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8045
Test Plan: Update unit test.
Differential Revision: D26899871
Pulled By: akankshamahajan15
fbshipit-source-id: 56adef52ee5af0fb3060b607c3af1ec01635fa2b
Summary:
Allow applications to implement a custom compaction filter and pass it to BlobDB.
The compaction filter's custom logic can operate on blobs.
To do so, application needs to subclass `CompactionFilter` abstract class and implement `FilterV2()` method.
Optionally, a method called `ShouldFilterBlobByKey()` can be implemented if application's custom logic rely solely
on the key to make a decision without reading the blob, thus saving extra IO. Examples can be found in
db/blob/db_blob_compaction_test.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7974
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D26509280
Pulled By: riversand963
fbshipit-source-id: 59f9ae5614c4359de32f4f2b16684193cc537b39
Summary:
Add support for IOTracing in blob files
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7958
Test Plan:
Add a new test and checked manually the trace_file for blob
files being recorded during read and write.
Reviewed By: ltamasi
Differential Revision: D26415950
Pulled By: akankshamahajan15
fbshipit-source-id: 49c2859b3a4f8307e7cb69a92704403a4da46d44
Summary:
The patch adds initial support for reading blobs to the batched `MultiGet` API.
The current implementation simply retrieves the blob values as the blob indexes
are encountered; that is, reads from blob files are currently not batched. (This
will be optimized in a separate phase.) In addition, the patch removes some dead
code related to BlobDB from the batched `MultiGet` implementation, namely the
`is_blob` / `is_blob_index` flags that are passed around in `DBImpl` and `MemTable` /
`MemTableListVersion`. These were never hooked up to anything and wouldn't
work anyways, since a single flag is not sufficient to communicate the "blobness"
of multiple key-values.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7766
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D25479290
Pulled By: ltamasi
fbshipit-source-id: 7aba2d290e31876ee592bcf1adfd1018713a8000
Summary:
This PR does a few things:
1. The MockFileSystem class was split out from the MockEnv. This change would theoretically allow a MockFileSystem to be used by other Environments as well (if we created a means of constructing one). The MockFileSystem implements a FileSystem in its entirety and does not rely on any Wrapper implementation.
2. Make the RocksDB test suite work when MOCK_ENV=1 and ENCRYPTED_ENV=1 are set. To accomplish this, a few things were needed:
- The tests that tried to use the "wrong" environment (Env::Default() instead of env_) were updated
- The MockFileSystem was changed to support the features it was missing or mishandled (such as recursively deleting files in a directory or supporting renaming of a directory).
3. Updated the test framework to have a ROCKSDB_GTEST_SKIP macro. This can be used to flag tests that are skipped. Currently, this defaults to doing nothing (marks the test as SUCCESS) but will mark the tests as SKIPPED when RocksDB is upgraded to a version of gtest that supports this (gtest-1.10).
I have run a full "make check" with MEM_ENV, ENCRYPTED_ENV, both, and neither under both MacOS and RedHat. A few tests were disabled/skipped for the MEM/ENCRYPTED cases. The error_handler_fs_test fails/hangs for MEM_ENV (presumably a timing problem) and I will introduce another PR/issue to track that problem. (I will also push a change to disable those tests soon). There is one more test in DBTest2 that also fails which I need to investigate or skip before this PR is merged.
Theoretically, this PR should also allow the test suite to run against an Env loaded from the registry, though I do not have one to try it with currently.
Finally, once this is accepted, it would be nice if there was a CircleCI job to run these tests on a checkin so this effort does not become stale. I do not know how to do that, so if someone could write that job, it would be appreciated :)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7566
Reviewed By: zhichao-cao
Differential Revision: D24408980
Pulled By: jay-zhuang
fbshipit-source-id: 911b1554a4d0da06fd51feca0c090a4abdcb4a5f
Summary:
The patch adds blob file support to the `Get` API by extending `Version` so that
whenever a blob reference is read from a file, the blob is retrieved from the corresponding
blob file and passed back to the caller. (This is assuming the blob reference is valid
and the blob file is actually part of the given `Version`.) It also introduces a cache
of `BlobFileReader`s called `BlobFileCache` that enables sharing `BlobFileReader`s
between callers. `BlobFileCache` uses the same backing cache as `TableCache`, so
`max_open_files` (if specified) limits the total number of open (table + blob) files.
TODO: proactively open/cache blob files and pin the cache handles of the readers in the
metadata objects similarly to what `VersionBuilder::LoadTableHandlers` does for
table files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7540
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D24260219
Pulled By: ltamasi
fbshipit-source-id: a8a2a4f11d3d04d6082201b52184bc4d7b0857ba
Levi Tamasi