Summary:
Add API to allow fetching expiration of a key with `Get()`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4227

Differential Revision: D9169897

Pulled By: yiwu-arbug

fbshipit-source-id: 2a6f216c493dc75731ddcef1daa689b517fab31b

Summary:
There are two issues with `VisibleToActiveSnapshot`:
1. If there are no snapshots, `oldest_snapshot` will be 0 and `VisibleToActiveSnapshot` will always return true. Since the method is used to decide whether it is safe to delete obsolete files, obsolete file won't be able to delete in this case.
2. The `auto` keyword of `auto snapshots = db_impl_->snapshots()` translate to a copy of `const SnapshotList` instead of a reference. Since copy constructor of `SnapshotList` is not defined, using the copy may yield unexpected result.

Issue 2 actually hide issue 1 from being catch by tests. During test `snapshots.empty()` can return false while it should actually be empty, and `snapshots.oldest()` return an invalid address, making `oldest_snapshot` being some random large number.

The issue was originally reported by BlobDB early adopter at Kuaishou.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4236

Differential Revision: D9188706

Pulled By: yiwu-arbug

fbshipit-source-id: a0f2624b927cf9bf28c1bb534784fee5d106f5ea

Summary:
- Add `--compression_max_dict_bytes` and `--compression_zstd_max_train_bytes` flags to stress test
- Randomly enable/disable the above flags in crash test
- Set `--compression_type=zstd` in FB-specific crash test runs
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4234

Differential Revision: D9187207

Pulled By: ajkr

fbshipit-source-id: 8d78cf8d8e1165f2cd1c32e069b73726b5bc1fd2

Summary:
Cleanup TTLExtractor interface. The original purpose of it is to allow our users keep using existing `Write()` interface but allow it to accept TTL via `TTLExtractor`. However the interface is confusing. Will replace it with something like `WriteWithTTL(batch, ttl)` in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4229

Differential Revision: D9174390

Pulled By: yiwu-arbug

fbshipit-source-id: 68201703d784408b851336ab4dd9b84188245b2d

Summary:
HashMayMatch is related to AddKey() instead of CreateFilter().
Also applies some minor Fixes #4191 #4200 #3910
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4202

Differential Revision: D9180945

Pulled By: maysamyabandeh

fbshipit-source-id: 6f07b81c5bb9bda5c0273475b486ba8a030471e6

Summary:
Hi, it would be great if we could expose this API, so that LogDevice can use it to track the total size of trash files and alarm if it grows too large in relation to disk size. There's probably other customers that would be interested in this as well. :)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4206

Differential Revision: D9115516

Pulled By: gdavidsson

fbshipit-source-id: f34993a940e39cb0a0b544ae8298546499b7e047

Summary:
In the past, we assume that a job modifies a single column family. Therefore, a job can create at most one superversion since each superversion corresponds to one column family. This assumption leads to the fact that a `JobContext` has only one member variable called `superversion_context`.
Now we want to support group flush of column families, indicating that each job can create multiple superversions. Therefore, we need to make the following change to accommodate this new feature.

Add a vector of `SuperVersionContext` to `JobContext` to support installing
superversions for multiple column families in one job context.

This PR is a subset of [PR 3752](https://github.com/facebook/rocksdb/pull/3752).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3949

Differential Revision: D8864895

Pulled By: riversand963

fbshipit-source-id: 5937a48817276370d3c8172db9c8aafc826d97ca

Summary:
The current verification logic does not consider the case in which multiple
threads (foreground and background) may execute `PurgeObsoleteFiles` function
simultaneously. Each invocation will trigger the callback adding elements to
a vector. Then we verify the elements in the vector, which can fail sometimes.

The solution is to give up checking the elements. Instead, we check the number
of OPTIONS file in the database dir.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4218

Differential Revision: D9128727

Pulled By: riversand963

fbshipit-source-id: 2b13b705fb21bc0ddd41940c4ec9b6b0c8d88224

Summary:
Fix lite build failure in db_bench due to trace/replay feature.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4225

Differential Revision: D9153303

Pulled By: sagar0

fbshipit-source-id: 9f7a8035429d0dcdbe99616d11389ed7bccf44be

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4219

Differential Revision: D9144294

Pulled By: riversand963

fbshipit-source-id: e46b72e5f8a149dc7a0512e38edcd0ddb0150f30

Summary:
This PR includes fixes for some bugs that I encountered while testing the Optimizer with ODS stats support.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4223

Differential Revision: D9140786

Pulled By: poojam23

fbshipit-source-id: 045cb3f27d075c2042040ac2d561938349419516

Summary:
This pull request adds a README file and a blog post for the Advisor tool. It also adds the missing tests for some Optimizer modules. Some comments are added to the classes being tested for improved readability.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4201

Reviewed By: maysamyabandeh

Differential Revision: D9125311

Pulled By: poojam23

fbshipit-source-id: aefcf2f06eaa05490cc2834ef5aa6e21f0d1dc55

Summary:
`CollapsedRangeDelMap` internally uses seqno zero as a sentinel value to
denote a gap between range tombstones or the end of range tombstones. It
therefore expects to never have consecutive sentinel tombstones.

However, since `DeleteRange` is now supported in `SstFileWriter`, an
ingested file may contain range tombstones, and that ingested file may
be assigned global seqno zero. When such tombstones are added to the
collapsed map, they resemble sentinel tombstones due to having seqno
zero. Then, the invariant mentioned above about never having consecutive
sentinel tombstones can be violated.

The symptom of this violation was dereferencing the `end()` iterator
(#4204). The fix in this PR is to not add range tombstones with seqno
zero to the collapsed map. They're not needed anyways since they can't
possibly cover anything (in case of a key and a range tombstone with the
same seqno, the key is visible).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4216

Differential Revision: D9121716

Pulled By: ajkr

fbshipit-source-id: f5b78a70bea9527354603ea7ac8542a7e2b6a210

Summary:
A framework for tracing and replaying RocksDB operations.

A binary trace file is created by capturing the DB operations, and it can be replayed back at the same rate using db_bench.

- Column-families are supported
- Multi-threaded tracing is supported.
- TraceReader and TraceWriter are exposed to the user, so that tracing to various destinations can be enabled (say, to other messaging/logging services). By default, a FileTraceReader and FileTraceWriter are implemented to capture to a file and replay from it.
- This is not yet ideal to be enabled in production due to large performance overhead, but it can be safely tried out in a shadow setup, say, for analyzing RocksDB operations.

Currently supported DB operations:
- Writes:
-- Put
-- Merge
-- Delete
-- SingleDelete
-- DeleteRange
-- Write
- Reads:
-- Get (point lookups)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3837

Differential Revision: D7974837

Pulled By: sagar0

fbshipit-source-id: 8ec65aaf336504bc1f6ed0feae67f6ed5ef97a72

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4203

Differential Revision: D9090912

Pulled By: fgwu

fbshipit-source-id: 6a68be83693ddf2a5c060290382141f0d2fb400b

Summary:
The cache line size was computed dynamically based on the length of the filter bits, and the number of cache-lines encoded in the footer. This calculation had to be dynamic in case users migrate their data between platforms with different cache line sizes. The downside, though, was bloom filter probing became expensive as it did integer mod and division.

However, since we know all possible cache line sizes are powers of two, we should be able to use bit shift to find the cache line, and bitwise-and to find the bit within the cache line. To do this, we compute the log-base-two of cache line size in the constructor, and use that in bitwise operations to replace division/mod.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4071

Differential Revision: D8684067

Pulled By: ajkr

fbshipit-source-id: 50298872fba5acd01e8269cd7abcc51a095e0f61

Summary:
Making generation of column families and keys virtual function so that
subclasses of StressTest can override them to provide custom parameter
generation for more flexibility. This will be useful for future tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4046

Differential Revision: D9073382

Pulled By: riversand963

fbshipit-source-id: 2754f0fdfa5c24d95c1f92d4944bc479552fb665

Summary:
RocksDB used to store global_seqno in external SST files written by
SstFileWriter. During file ingestion, RocksDB uses `pwrite` to update the
`global_seqno`. Since random write is not supported in some non-POSIX compliant
file systems, external SST file ingestion is not supported on these file
systems. To address this limitation, we no longer update `global_seqno` during
file ingestion. Later RocksDB uses the MANIFEST and other information in table
properties to deduce global seqno for externally-ingested SST files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4172

Differential Revision: D8961465

Pulled By: riversand963

fbshipit-source-id: 4382ec85270a96be5bc0cf33758ca2b167b05071

Summary:
Added DataBlockIndexType option in BlockBasedTableOptions.
```
enum DataBlockIndexType : char {
    kDataBlockBinarySearch = 0, // traditional block type
    kDataBlockHashIndex = 1, // additional hash index appended to the end.
};
```
The default type is the traditional binary seek option: `kDataBlockBinarySearch`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4150

Differential Revision: D8895958

Pulled By: fgwu

fbshipit-source-id: 480adef48104cf11d30db3bad9a73f98b4a80c10

Summary:
If crash happen after a hard link established, Recover function may reuse the file number that has already assigned to the internal file, and this will overwrite the external file. To protect the external file, we have to make sure the file number will never being reused.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/4099

Differential Revision: D9034092

Pulled By: riversand963

fbshipit-source-id: 3f1a737440b86aa2ef01673e5013aacbb7c33e28

Summary:
The inline doc was incorrectly mentioned a return status while the function does not return a value.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4196

Differential Revision: D9030927

Pulled By: maysamyabandeh

fbshipit-source-id: 07c34dc6bf521021bf790ac1bfedb676171129ec

Summary:
max_total_wal_size takes effect only when there are more than one column families. The patch clarify that in the inline docs

Closes https://github.com/facebook/rocksdb/issues/4180
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4194

Differential Revision: D9028767

Pulled By: maysamyabandeh

fbshipit-source-id: 8d730ca7f15e76e7ee9ff88b2b48030b2d1b7078

Summary:
In https://github.com/facebook/rocksdb/pull/3934 we introduced advisor scripts that make suggestions in the config options based on the log file and stats from a run of rocksdb. The optimizer runs the advisor on a benchmark application in a loop and automatically applies the suggested changes until the config options are optimized. This is a work in progress and the patch is the initial skeleton for the optimizer. The sample application that is run in the loop is currently dbbench.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4169

Reviewed By: maysamyabandeh

Differential Revision: D9023671

Pulled By: poojam23

fbshipit-source-id: a6192d475c462cf6eb2b316716f97cb400fcb64d

Summary:
Usually when using cscope, the query results contain a lot of function calls in test, making it hard to browse. So this PR aims to provide an option to exclude test source files.

Add a new PHONY target, tags0, to exclude test source files while using cscope.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4190

Differential Revision: D9015901

Pulled By: riversand963

fbshipit-source-id: ea9a45756ccff5b26344d37e9ff1c02c5d9736d6

Summary:
995fcf75 has a bug: ReleaseFileNumberFromPendingOutputs() added is not protected by the DB mutex. Fix it by grabbing the lock for this operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4189

Differential Revision: D9015447

Pulled By: siying

fbshipit-source-id: b8506e09a96c3f95a6fe32b5ca5fcdb9bee88937

Summary:
92ee3350 introduces an out-of-bound check in BlockBasedTableIterator::Valid(). However, this flag is not reset when re-seeking in backward direction. This caused the iterator to be invalide by mistake. Fix it by always resetting the out-of-bound flag in every seek.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4187

Differential Revision: D8996600

Pulled By: siying

fbshipit-source-id: b6235ea614f71381e50e7904c4fb036300604ac1

Summary:
Given that we have cut 5.15, we should bump the version number to the next
version, i.e. 5.16.
Also update HISTORY.md
cc sagar0
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4176

Differential Revision: D8977965

Pulled By: riversand963

fbshipit-source-id: 481d75d2f446946f0eb2afb7e94ef894c8c87e1e

Summary:
The first step of the `DataBlockHashIndex` implementation. A string based hash table is implemented and unit-tested.

`DataBlockHashIndexBuilder`: `Add()` takes pairs of `<key, restart_index>`, and formats it into a string when `Finish()` is called.
`DataBlockHashIndex`: initialized by the formatted string, and can interpret it as a hash table. Lookup for a key is supported by iterator operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4139

Reviewed By: sagar0

Differential Revision: D8866764

Pulled By: fgwu

fbshipit-source-id: 7f015f0098632c65979a22898a50424384730b10

Summary:
This adds support for writing unprepared batches based on size defined in `TransactionOptions::max_write_batch_size`. This is done by overriding methods that modify data (Put/Delete/SingleDelete/Merge) and checking first if write batch size has exceeded threshold. If so, the write batch is written to DB as an unprepared batch.

Support for Commit/Rollback for unprepared batch is added as well. This has been done by simply extending the WritePrepared Commit/Rollback logic to take care of all unprep_seq numbers either when updating prepare heap, or adding to commit map. For updating the commit map, this logic exists inside `WriteUnpreparedCommitEntryPreReleaseCallback`.

A test change was also made to have transactions unregister themselves when committing without prepare. This is because with write unprepared, there may be unprepared entries (which act similarly to prepared entries) already when a commit is done without prepare.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4104

Differential Revision: D8785717

Pulled By: lth

fbshipit-source-id: c02006e281ec1ce00f628e2a7beec0ee73096a91

Summary:
The member msgs of class Status contains all types of status messages.
When users dump a Status object, msgs will confuse users. So move it out
of class Status by making it as file-local static variable.

Closes #3831 .
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4144

Differential Revision: D8941419

Pulled By: sagar0

fbshipit-source-id: 56b0510258465ff26db15aa6b04e01532e053e3d

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4165

Differential Revision: D8955531

Pulled By: sagar0

fbshipit-source-id: 97d5a1375e200bde3c6414f94703504a4ed7536a

Summary:
db_stress doesn't cover upper or lower bound in iterators. Try to cover it by randomly assigning a random one. Also in prefix scan tests, with 50% of the chance, set next prefix as the upper bound.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4162

Differential Revision: D8953507

Pulled By: siying

fbshipit-source-id: f0f04e9cb6c07cbebbb82b892ca23e0daeea708b

Summary:
Currently in `Version::Get` when reporting ticker stats stored in `GetContext`, there is a big for-loop through all `Ticker` which adds unnecessary cost to overall CPU usage. We can optimize by storing only ticker values that are used in `Get()` calls in a new struct `GetContextStats` since only a small fraction of all tickers are used in `Get()` calls. For comparison, with the new approach we only need to visit 17 values while old approach will require visiting 100+ `Ticker`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3490

Differential Revision: D6969154

Pulled By: miasantreble

fbshipit-source-id: fc27072965a3a94125a3e6883d20dafcf5b84029

Summary:
When running the tracing and analyzing, I found that MergeRandom benchmark in db_bench only access the default column family even the -num_column_families is specified > 1.

changes: Using the db_with_cfh as DB to randomly select the column family to execute the Merge operation if -num_column_families is specified > 1.

Tested with make asan_check and verified in tracing
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4155

Differential Revision: D8907888

Pulled By: zhichao-cao

fbshipit-source-id: 2b4bc8fe0e99c8f262f5be6b986c7025d62cf850

Summary:
Lint is not happy with some new code recently committed. Format them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4161

Differential Revision: D8940582

Pulled By: siying

fbshipit-source-id: c9b43b1ef8c88b5e923911058b44eb77234b36b7

Summary:
Right now we use one hard-coded prefetch size to prefetch data from the tail of the SST files. However, this may introduce a waste for some use cases, while not efficient for others.
Introduce a way to adjust this prefetch size by tracking 32 recent times, and pick a value with which the wasted read is less than 10%
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4156

Differential Revision: D8916847

Pulled By: siying

fbshipit-source-id: 8413f9eb3987e0033ed0bd910f83fc2eeaaf5758

Summary:
The properties meta-block should come at the end since we always need to
read it when opening a file, unlike index/filter/other meta-blocks, which
are sometimes read depending on the user's configuration. This ordering
will allow us to (in a future PR) do a small readahead on the end of the file
to read properties and meta-index blocks with one I/O.

The bulk of this PR is a refactoring of the `BlockBasedTableBuilder::Finish`
function. It was previously too large with inconsistent error handling, which
made it difficult to change. So I broke it up into one function per meta-block
write, and tried to make error handling consistent within those functions.
Then reordering the metablocks was trivial -- just reorder the calls to these
helper functions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4158

Differential Revision: D8921705

Pulled By: ajkr

fbshipit-source-id: 96c9cc3182eb1adf11af46adab79dbeba7b12fcc

Summary:
PR #3944 introduces group commit of `VersionEdit` in MANIFEST. The
implementation has a bug. When updating the log file number of each column
family, we must consider only `VersionEdit`s that operate on the same column
family. Otherwise, a column family may accidentally set its log file number
higher than actual value, indicating that log files with smaller file number
will be ignored, thus causing some updates to be lost.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4157

Differential Revision: D8916650

Pulled By: riversand963

fbshipit-source-id: 8f456cf688f17bf35ad87b38e30e899aa162f201

Summary:
In all cases during `BlockBasedTable::Open`, we issue at least three read requests to the file's tail: (1) footer, (2) metaindex block, and (3) properties block. Depending on the config, we may also read other metablocks like filter and index.

This PR issues smaller readahead when we expect to do only the three necessary reads mentioned above. Then, 4KB should be enough (ignoring the case where there are lots of user-defined properties). We can keep doing 512KB readahead when additional reads are expected.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4159

Differential Revision: D8924002

Pulled By: ajkr

fbshipit-source-id: cfc713275de4d05ce11f18571f1d72e27ccd3356

Summary: Windows requires new/delete for memory allocations to be overriden. Refactor to be less intrusive.

Differential Revision: D8878047

Pulled By: siying

fbshipit-source-id: 35f2b5fec2f88ea48c9be926539c6469060aab36