Summary:
PR https://github.com/facebook/rocksdb/issues/9888 started to enforce the contract of single delete described in https://github.com/facebook/rocksdb/wiki/Single-Delete.
For some of existing use cases, it is desirable to have a transition during which compaction will not fail
if the contract is violated. Therefore, we add a temporary option `enforce_single_del_contracts` to allow
application to opt out from this new strict behavior. Once transition completes, the flag can be set to `true` again.
In a future release, the option will be removed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9983
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D36333672
Pulled By: riversand963
fbshipit-source-id: dcb703ea0ed08076a1422f1bfb9914afe3c2caa2
Summary:
ToString() is created as some platform doesn't support std::to_string(). However, we've already used std::to_string() by mistake for 16 months (in db/db_info_dumper.cc). This commit just remove ToString().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9955
Test Plan: Watch CI tests
Reviewed By: riversand963
Differential Revision: D36176799
fbshipit-source-id: bdb6dcd0e3a3ab96a1ac810f5d0188f684064471
Summary:
**This PR does not affect the functionality of `DB` and write-committed transactions.**
`CompactionIterator` uses `KeyCommitted(seq)` to determine if a key in the database is committed.
As the name 'write-committed' implies, if write-committed policy is used, a key exists in the database only if
it is committed. In fact, the implementation of `KeyCommitted()` is as follows:
```
inline bool KeyCommitted(SequenceNumber seq) {
// For non-txn-db and write-committed, snapshot_checker_ is always nullptr.
return snapshot_checker_ == nullptr ||
snapshot_checker_->CheckInSnapshot(seq, kMaxSequence) == SnapshotCheckerResult::kInSnapshot;
}
```
With that being said, we focus on write-prepared/write-unprepared transactions.
A few notes:
- A key can exist in the db even if it's uncommitted. Therefore, we rely on `snapshot_checker_` to determine data visibility. We also require that all writes go through transaction API instead of the raw `WriteBatch` + `Write`, thus at most one uncommitted version of one user key can exist in the database.
- `CompactionIterator` outputs a key as long as the key is uncommitted.
Due to the above reasons, it is possible that `CompactionIterator` decides to output an uncommitted key without
doing further checks on the key (`NextFromInput()`). By the time the key is being prepared for output, the key becomes
committed because the `snapshot_checker_(seq, kMaxSequence)` becomes true in the implementation of `KeyCommitted()`.
Then `CompactionIterator` will try to zero its sequence number and hit assertion error if the key is a tombstone.
To fix this issue, we should make the `CompactionIterator` see a consistent view of the input keys. Note that
for write-prepared/write-unprepared, the background flush/compaction jobs already take a "job snapshot" before starting
processing keys. The job snapshot is released only after the entire flush/compaction finishes. We can use this snapshot
to determine whether a key is committed or not with minor change to `KeyCommitted()`.
```
inline bool KeyCommitted(SequenceNumber sequence) {
// For non-txn-db and write-committed, snapshot_checker_ is always nullptr.
return snapshot_checker_ == nullptr ||
snapshot_checker_->CheckInSnapshot(sequence, job_snapshot_) ==
SnapshotCheckerResult::kInSnapshot;
}
```
As a result, whether a key is committed or not will remain a constant throughout compaction, causing no trouble
for `CompactionIterator`s assertions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9830
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D35561162
Pulled By: riversand963
fbshipit-source-id: 0e00d200c195240341cfe6d34cbc86798b315b9f
Summary:
Options `preserve_deletes` and `iter_start_seqnum` have been removed since 7.0.
This PR removes dead code related to these two removed options.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9825
Test Plan: make check
Reviewed By: akankshamahajan15
Differential Revision: D35517950
Pulled By: riversand963
fbshipit-source-id: 86282ce5ec4087acb94a06a42a1b6d55b1715482
Summary:
The patch adds a new BlobDB configuration option `blob_compaction_readahead_size`
that can be used to enable prefetching data from blob files during compaction.
This is important when using storage with higher latencies like HDDs or remote filesystems.
If enabled, prefetching is used for all cases when blobs are read during compaction,
namely garbage collection, compaction filters (when the existing value has to be read from
a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187
Test Plan: Ran `make check` and the stress/crash test.
Reviewed By: riversand963
Differential Revision: D32565512
Pulled By: ltamasi
fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d
Summary:
For multiple versions (ts + seq) of the same user key, if they cross the boundary of `full_history_ts_low_`,
we should retain the version that is visible to the `full_history_ts_low_`. Namely, we keep the internal key
with the largest timestamp smaller than `full_history_ts_low`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9116
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D32261514
Pulled By: riversand963
fbshipit-source-id: e10f47c254c04c05261440051e4f50cb7d95474e
Summary:
There were three implementations of VectorIterator (util/vector_iterator, test_util/testutil.h and LoggingForwardVectorIterator). Merged them into one class to increase code coverage/testing and reduce duplication.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8901
Reviewed By: pdillinger
Differential Revision: D31022673
Pulled By: mrambacher
fbshipit-source-id: 8e3acbd2dfd60b4df609d02cc72846de2389d531
Summary:
Added support for SingleDelete for user-defined timestamps. Users can now Get and Iterate over keys deleted with SingleDelete. It also includes changes in CompactionIterator which preserves the same user key with different timestamps, unless the timestamp is below a certain threshold full_history_ts_low.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8921
Test Plan: Added new unit tests
Reviewed By: riversand963
Differential Revision: D31098191
Pulled By: akankshamahajan15
fbshipit-source-id: 78a59ef4b4884ae324fcd10f56e62a27d5ee2f49
Summary:
In debug mode, we are seeing assertion failure as follows
```
db/compaction/compaction_iterator.cc:980: void rocksdb::CompactionIterator::PrepareOutput(): \
Assertion `ikey_.type != kTypeDeletion && ikey_.type != kTypeSingleDeletion' failed.
```
It is caused by releasing earliest snapshot during compaction between the execution of
`NextFromInput()` and `PrepareOutput()`.
In one case, as demonstrated in unit test `WritePreparedTransaction.ReleaseEarliestSnapshotDuringCompaction_WithSD2`,
incorrect result may be returned by a following range scan if we disable assertion, as in opt compilation
level: the SingleDelete marker's sequence number is zeroed out, but the preceding PUT is also
outputted to the SST file after compaction. Due to the logic of DBIter, the PUT will not be
skipped and will be returned by iterator in range scan. https://github.com/facebook/rocksdb/issues/8661 illustrates what happened.
Fix by taking a more conservative approach: make compaction zero out sequence number only
if key is in the earliest snapshot when the compaction starts.
Another assertion failure is
```
Assertion `current_user_key_snapshot_ == last_snapshot' failed.
```
It's caused by releasing the snapshot between the PUT and SingleDelete during compaction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8608
Test Plan: make check
Reviewed By: jay-zhuang
Differential Revision: D30145645
Pulled By: riversand963
fbshipit-source-id: 699f58e66faf70732ad53810ccef43935d3bbe81
Summary:
The patch builds on `BlobGarbageMeter` and `BlobCountingIterator`
(introduced in https://github.com/facebook/rocksdb/issues/8426 and
https://github.com/facebook/rocksdb/issues/8443 respectively)
and ties it all together. It measures the amount of garbage
generated by a compaction and logs the corresponding `BlobFileGarbage`
records as part of the compaction job's `VersionEdit`. Note: in order
to have accurate results, `kRemoveAndSkipUntil` for compaction filters
is implemented using iteration.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8450
Test Plan: Ran `make check` and the crash test script.
Reviewed By: jay-zhuang
Differential Revision: D29338207
Pulled By: ltamasi
fbshipit-source-id: 4381c432ac215139439f6d6fb801a6c0e4d8c128
Summary:
Added the ability to cancel an in-progress range compaction by storing to an atomic "canceled" variable pointed to within the CompactRangeOptions structure.
Tested via two tests added to db_tests2.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8351
Reviewed By: ajkr
Differential Revision: D28808894
Pulled By: ddevec
fbshipit-source-id: cb321361c9e23b084b188bb203f11c375a22c2dd
Summary:
There is a small `SingleDelete` related optimization in the
`CompactionIterator` code: when a `SingleDelete`-`Put` pair is preserved
solely for the purposes of transaction conflict checking, the value
itself gets cleared. (This is referred to as "optimization 3" in the
`CompactionIterator` code.) Though the rest of the code got updated to
support `SingleDelete`'ing blob indexes, this chunk was apparently
missed, resulting in an assertion failure (or `ROCKS_LOG_FATAL` in release
builds) when triggered. Note: in addition to clearing the value, we also
need to update the type of the KV to regular value when dealing with
blob indexes here.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7904
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D26118009
Pulled By: ltamasi
fbshipit-source-id: 6bf78043d20265e2b15c2e1ab8865025040c42ae
Summary:
The patch adds basic garbage collection support to the integrated BlobDB
implementation. Valid blobs residing in the oldest blob files are relocated
as they are encountered during compaction. The threshold that determines
which blob files qualify is computed based on the configuration option
`blob_garbage_collection_age_cutoff`, which was introduced in https://github.com/facebook/rocksdb/issues/7661 .
Once a blob is retrieved for the purposes of relocation, it passes through the
same logic that extracts large values to blob files in general. This means that
if, for instance, the size threshold for key-value separation (`min_blob_size`)
got changed or writing blob files got disabled altogether, it is possible for the
value to be moved back into the LSM tree. In particular, one way to re-inline
all blob values if needed would be to perform a full manual compaction with
`enable_blob_files` set to `false`, `enable_blob_garbage_collection` set to
`true`, and `blob_file_garbage_collection_age_cutoff` set to `1.0`.
Some TODOs that I plan to address in separate PRs:
1) We'll have to measure the amount of new garbage in each blob file and log
`BlobFileGarbage` entries as part of the compaction job's `VersionEdit`.
(For the time being, blob files are cleaned up solely based on the
`oldest_blob_file_number` relationships.)
2) When compression is used for blobs, the compression type hasn't changed,
and the blob still qualifies for being written to a blob file, we can simply copy
the compressed blob to the new file instead of going through decompression
and compression.
3) We need to update the formula for computing write amplification to account
for the amount of data read from blob files as part of GC.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7694
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D25069663
Pulled By: ltamasi
fbshipit-source-id: bdfa8feb09afcf5bca3b4eba2ba72ce2f15cd06a
Summary:
`CompactionProxy` is currently both a concrete class used for actual `Compaction`s
and a base class that `FakeCompaction` (which is used in `compaction_iterator_test`)
is derived from. This is bad from an OO design standpoint, and also results in
`FakeCompaction` containing an (uninitialized and unused) `Compaction*` member.
The patch fixes this by making `CompactionProxy` a pure interface and introducing
a separate concrete class `RealCompaction` for non-test/non-fake compactions. It
also removes an unused parameter from the virtual method `level`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7662
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D24907680
Pulled By: ltamasi
fbshipit-source-id: c100ecb1beef4b0ada35e799116c5bda71719ee7
Summary:
https://github.com/facebook/rocksdb/issues/7556 introduced support for compaction iterator to perform timestamp-aware garbage collection.
However, there was a bug. The comparison between `ikey_.user_key` and `current_user_key_` should happen
before `key_ = current_key_.SetInternalKey(key_, &ikey_);` (line 336 of compaction_iterator.cc).
Otherwise, after this line, `current_key_` is always the same as `ikey_.user_key`.
This PR also re-arranged the order of some data members because some of them are state variables of `CompactionIterator` while others are inputs from callers.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7645
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D24845028
Pulled By: riversand963
fbshipit-source-id: c7e79914832701462b86867e8463cd463b6c0c25
Summary:
Fixes Issue https://github.com/facebook/rocksdb/issues/7497
When allow_data_in_errors db_options is set, log error key details in `ParseInternalKey()`
Have fixed most of the calls. Have few TODOs still pending - because have to make more deeper changes to pass in the allow_data_in_errors flag. Will do those in a separate PR later.
Tests:
- make check
- some of the existing tests that exercise the "internal key too small" condition are: dbformat_test, cuckoo_table_builder_test
- some of the existing tests that exercise the corrupted key path are: corruption_test, merge_helper_test, compaction_iterator_test
Example of new status returns:
- Key too small - `Corrupted Key: Internal Key too small. Size=5`
- Corrupt key with allow_data_in_errors option set to false: `Corrupted Key: '<redacted>' seq:3, type:3`
- Corrupt key with allow_data_in_errors option set to true: `Corrupted Key: '61' seq:3, type:3`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7515
Reviewed By: ajkr
Differential Revision: D24240264
Pulled By: ramvadiv
fbshipit-source-id: bc48f5d4475ac19d7713e16df37505b31aac42e7
Summary:
Add a threshold timestamp, full_history_ts_low_ of type `std::string*` to
`CompactionIterator`, so that RocksDB can also perform garbage collection during
compaction.
* If full_history_ts_low_ is nullptr, then compaction iterator does not perform
GC, preserving all timestamp history for all keys. Compaction iterator will
treat user key with different timestamps as different user keys.
* If full_history_ts_low_ is not nullptr, then compaction iterator performs
GC. GC will look at keys older than `*full_history_ts_low_` and determine their
eligibility based on factors including snapshots.
Current rules of GC:
* If an internal key is in the same snapshot as a previous counterpart
with the same user key, and this key is eligible for GC, and the key is
not single-delete or merge operand, then this key can be dropped. Note
that the previous internal key cannot be a merge operand either.
* If a tombstone is the most recent one in the earliest snapshot and it
is eligible for GC, and keyNotExistsBeyondLevel() is true, then this
tombstone can be dropped.
* If a tombstone is the most recent one in a snapshot and it is eligible
for GC, and the compaction is at bottommost level, then all other older
internal keys of the same user key must also be eligible for GC, thus
can be dropped
* Single-delete, delete-range and merge are not currently supported.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7556
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D24507728
Pulled By: riversand963
fbshipit-source-id: 3c09c7301f41eed76dfcf4d1527e68cf6e0a8bb3
Summary:
Add a new Option "allow_data_in_errors". When it's set by users, it allows them to opt-in to get error messages containing corrupted keys/values. Corrupt keys, values will be logged in the messages, logs, status etc. that will help users with the useful information regarding affected data.
By default value is set false to prevent users data to be exposed in the messages.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7420
Test Plan:
1. make check -j64
2. Add a new test case
Reviewed By: ajkr
Differential Revision: D23835028
Pulled By: akankshamahajan15
fbshipit-source-id: 8d2eba8fb898e79fcf1fccc07295065a75eb59b1
Summary:
Fix few test cases and add them in ASSERT_STATUS_CHECKED build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7427
Test Plan:
1. ASSERT_STATUS_CHECKED=1 make -j48 check,
2. travis build for ASSERT_STATUS_CHECKED,
3. Without ASSERT_STATUS_CHECKED: make check -j64, CircleCI build and travis build
Reviewed By: pdillinger
Differential Revision: D23909983
Pulled By: akankshamahajan15
fbshipit-source-id: 42d7e4aea972acb9fcddb7ca73fcb82f93272434
Summary:
The patch adds support for writing blob files during flush by integrating
`BlobFileBuilder` with the flush logic, most importantly, `BuildTable` and
`CompactionIterator`. If `enable_blob_files` is set, large values are extracted
to blob files and replaced with references. The resulting blob files are then
logged to the MANIFEST as part of the flush job's `VersionEdit` and
added to the `Version`, similarly to table files. Errors related to writing
blob files fail the flush, and any blob files written by such jobs are immediately
deleted (again, similarly to how SST files are handled). In addition, the patch
extends the logging and statistics around flushes to account for the presence
of blob files (e.g. `InternalStats::CompactionStats::bytes_written`, which is
used for calculating write amplification, now considers the blob files as well).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7345
Test Plan: Tested using `make check` and `db_bench`.
Reviewed By: riversand963
Differential Revision: D23506369
Pulled By: ltamasi
fbshipit-source-id: 646885f22dfbe063f650d38a1fedc132f499a159
Summary:
- Closes https://github.com/facebook/rocksdb/issues/6490
- Currently MERGEs are converted to PUTs at bottom or compaction has reached the beginning of the key, this can wrongly cover a PUT future base case.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7166
Test Plan:
- Automated: `make all check`
- Manual: With `allow_ingest_behind = true`, add Merge operations to a key then run compaction. Then run ingesting external files to make sure the base case is probably compacted with existing Merges.
Reviewed By: cheng-chang
Differential Revision: D23325425
Pulled By: ajkr
fbshipit-source-id: 3eb415eb7b381b5453e45245393566153b1abb68
Summary:
This reverts commit 8d87e9cea1.
Based on offline discussions, it's too early to upgrade to gtest 1.10, as it prevents some developers from using an older version of gtest to integrate to some other systems. Revert it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6923
Reviewed By: pdillinger
Differential Revision: D21864799
fbshipit-source-id: d0726b1ff649fc911b9378f1763316200bd363fc
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:
There are too many types of files under util/. Some test related files don't belong to there or just are just loosely related. Mo
ve them to a new directory test_util/, so that util/ is cleaner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5377
Differential Revision: D15551366
Pulled By: siying
fbshipit-source-id: 0f5c8653832354ef8caa31749c0143815d719e2c
Summary:
Compaction iterator keep a copy of list of live snapshots at the beginning of compaction, and then query snapshot checker to verify if values of a sequence number is visible to these snapshots. However when the snapshot is released in the middle of compaction, the snapshot checker implementation (i.e. WritePreparedSnapshotChecker) may remove info with the snapshot and may report incorrect result, which lead to values being compacted out when it shouldn't. This patch conservatively keep the values if snapshot checker determines that the snapshots is released.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4858
Differential Revision: D13617146
Pulled By: maysamyabandeh
fbshipit-source-id: cf18a94f6f61a94bcff73c280f117b224af5fbc3
Summary:
Now that v2 is fully functional, the v1 aggregator is removed.
The v2 aggregator has been renamed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4778
Differential Revision: D13495930
Pulled By: abhimadan
fbshipit-source-id: 9d69500a60a283e79b6c4fa938fc68a8aa4d40d6
Summary:
RangeDelAggregatorV2 now supports ShouldDelete calls on
snapshot stripes and creation of range tombstone compaction iterators.
RangeDelAggregator is no longer used on any non-test code path, and will
be removed in a future commit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4758
Differential Revision: D13439254
Pulled By: abhimadan
fbshipit-source-id: fe105bcf8e3d4a2df37a622d5510843cd71b0401
Summary:
This PR fixes issue 3842. We drop deletion markers iff
1. We are the bottom most level AND
2. All other occurrences of the key are in the same snapshot range as the delete
I've also enhanced db_stress_test to add an option that does a full compare of the keys. This is done by a single thread (thread # 0). For tests I've run (so far)
make check -j64
db_stress
db_stress --acquire_snapshot_one_in=1000 --ops_per_thread=100000 /* to verify that new code doesnt break existing tests */
./db_stress --compare_full_db_state_snapshot=true --acquire_snapshot_one_in=1000 --ops_per_thread=100000 /* to verify new test code */
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4289
Differential Revision: D9491165
Pulled By: shrikanthshankar
fbshipit-source-id: ce144834f31736c189aaca81bed356ba990331e2
Summary:
We want to sample the file I/O issued by RocksDB and report the function calls. This requires us to include the file paths otherwise it's hard to tell what has been going on.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4039
Differential Revision: D8670178
Pulled By: riversand963
fbshipit-source-id: 97ee806d1c583a2983e28e213ee764dc6ac28f7a
Summary:
For example calling CompactionFilter is always timed and gives the user no way to disable.
This PR will disable the timer if `Statistics::stats_level_` (which is part of DBOptions) is `kExceptDetailedTimers`
Closes https://github.com/facebook/rocksdb/pull/4029
Differential Revision: D8583670
Pulled By: miasantreble
fbshipit-source-id: 913be9fe433ae0c06e88193b59d41920a532307f
Summary:
Red diff to remove existing implementation of garbage collection. The current approach is reference counting kind of approach and require a lot of effort to get the size counter right on compaction and deletion. I'm going to go with a simple mark-sweep kind of approach and will send another PR for that.
CompactionEventListener was added solely for blob db and it adds complexity and overhead to compaction iterator. Removing it as well.
Closes https://github.com/facebook/rocksdb/pull/3551
Differential Revision: D7130190
Pulled By: yiwu-arbug
fbshipit-source-id: c3a375ad2639a3f6ed179df6eda602372cc5b8df
Summary:
CompactionIterator invoke MergeHelper::MergeUntil() to do partial merge between snapshot boundaries. Previously it only depend on sequence number to tell snapshot boundary, but we also need to make use of snapshot_checker to verify visibility of the merge operands to the snapshots. For example, say there is a snapshot with seq = 2 but only can see data with seq <= 1. There are three merges, each with seq = 1, 2, 3. A correct compaction output would be (1),(2+3). Without taking snapshot_checker into account when generating merge result, compaction will generate output (1+2),(3).
By filtering uncommitted keys with read callback, the read path already take care of merges well and don't need additional updates.
Closes https://github.com/facebook/rocksdb/pull/3475
Differential Revision: D6926087
Pulled By: yiwu-arbug
fbshipit-source-id: 8f539d6f897cfe29b6dc27a8992f68c2a629d40a
Summary:
Update compaction_iterator_test with write-prepared transaction DB related tests. Transaction related tests are group in CompactionIteratorWithSnapshotCheckerTest. The existing test are duplicated to make them also test with dummy SnapshotChecker that will say every key is visible to every snapshot (this is okay, we still compare sequence number to verify visibility). Merge related tests are disabled and will be revisit in another PR.
Existing db_iterator_tests are also duplicated to test with dummy read_callback that will say every key is committed.
Closes https://github.com/facebook/rocksdb/pull/3466
Differential Revision: D6909253
Pulled By: yiwu-arbug
fbshipit-source-id: 2ae4656b843a55e2e9ff8beecf21f2832f96cd25
Summary:
The motivation for this PR is to add to RocksDB support for differential (incremental) snapshots, as snapshot of the DB changes between two points in time (one can think of it as diff between to sequence numbers, or the diff D which can be thought of as an SST file or just set of KVs that can be applied to sequence number S1 to get the database to the state at sequence number S2).
This feature would be useful for various distributed storages layers built on top of RocksDB, as it should help reduce resources (time and network bandwidth) needed to recover and rebuilt DB instances as replicas in the context of distributed storages.
From the API standpoint that would like client app requesting iterator between (start seqnum) and current DB state, and reading the "diff".
This is a very draft PR for initial review in the discussion on the approach, i'm going to rework some parts and keep updating the PR.
For now, what's done here according to initial discussions:
Preserving deletes:
- We want to be able to optionally preserve recent deletes for some defined period of time, so that if a delete came in recently and might need to be included in the next incremental snapshot it would't get dropped by a compaction. This is done by adding new param to Options (preserve deletes flag) and new variable to DB Impl where we keep track of the sequence number after which we don't want to drop tombstones, even if they are otherwise eligible for deletion.
- I also added a new API call for clients to be able to advance this cutoff seqnum after which we drop deletes; i assume it's more flexible to let clients control this, since otherwise we'd need to keep some kind of timestamp < -- > seqnum mapping inside the DB, which sounds messy and painful to support. Clients could make use of it by periodically calling GetLatestSequenceNumber(), noting the timestamp, doing some calculation and figuring out by how much we need to advance the cutoff seqnum.
- Compaction codepath in compaction_iterator.cc has been modified to avoid dropping tombstones with seqnum > cutoff seqnum.
Iterator changes:
- couple params added to ReadOptions, to optionally allow client to request internal keys instead of user keys (so that client can get the latest value of a key, be it delete marker or a put), as well as min timestamp and min seqnum.
TableCache changes:
- I modified table_cache code to be able to quickly exclude SST files from iterators heep if creation_time on the file is less then iter_start_ts as passed in ReadOptions. That would help a lot in some DB settings (like reading very recent data only or using FIFO compactions), but not so much for universal compaction with more or less long iterator time span.
What's left:
- Still looking at how to best plug that inside DBIter codepath. So far it seems that FindNextUserKeyInternal only parses values as UserKeys, and iter->key() call generally returns user key. Can we add new API to DBIter as internal_key(), and modify this internal method to optionally set saved_key_ to point to the full internal key? I don't need to store actual seqnum there, but I do need to store type.
Closes https://github.com/facebook/rocksdb/pull/2999
Differential Revision: D6175602
Pulled By: mikhail-antonov
fbshipit-source-id: c779a6696ee2d574d86c69cec866a3ae095aa900
Summary:
Update Compaction/Flush to support WritePreparedTxnDB: Add SnapshotChecker which is a proxy to query WritePreparedTxnDB::IsInSnapshot. Pass SnapshotChecker to DBImpl on WritePreparedTxnDB open. CompactionIterator use it to check if a key has been committed and if it is visible to a snapshot. In CompactionIterator:
* check if key has been committed. If not, output uncommitted keys AS-IS.
* use SnapshotChecker to check if key is visible to a snapshot when in need.
* do not output key with seq = 0 if the key is not committed.
Closes https://github.com/facebook/rocksdb/pull/2926
Differential Revision: D5902907
Pulled By: yiwu-arbug
fbshipit-source-id: 945e037fdf0aa652dc5ba0ad879461040baa0320
Summary:
Added a function `MergeOperator::DoesAllowSingleMergeOperand()` to allow invoking a merge operator even with a single merge operand, if overriden.
This is needed for Cassandra-on-RocksDB work. All Cassandra writes are through merges and this will allow a single merge-value to be updated in the merge-operator invoked via a compaction, if needed, due to an expired TTL.
Closes https://github.com/facebook/rocksdb/pull/2721
Differential Revision: D5608706
Pulled By: sagar0
fbshipit-source-id: f299f9f91c4d1ac26e48bd5906e122c1c5e5f3fc
Summary:
This reverts the previous commit 1d7048c598, which broke the build.
Did a `git revert 1d7048c`.
Closes https://github.com/facebook/rocksdb/pull/2627
Differential Revision: D5476473
Pulled By: sagar0
fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06
Summary: This uses `clang-tidy` to comment out unused parameters (in functions, methods and lambdas) in fbcode. Cases that the tool failed to handle are fixed manually.
Reviewed By: igorsugak
Differential Revision: D5454343
fbshipit-source-id: 5dee339b4334e25e963891b519a5aa81fbf627b2
Summary:
First cut for early review; there are few conceptual points to answer and some code structure issues.
For conceptual points -
- restriction-wise, we're going to disallow ingest_behind if (use_seqno_zero_out=true || disable_auto_compaction=false), the user is responsible to properly open and close DB with required params
- we wanted to ingest into reserved bottom most level. Should we fail fast if bottom level isn't empty, or should we attempt to ingest if file fits there key-ranges-wise?
- Modifying AssignLevelForIngestedFile seems the place we we'd handle that.
On code structure - going to refactor GenerateAndAddExternalFile call in the test class to allow passing instance of IngestionOptions, that's just going to incur lots of changes at callsites.
Closes https://github.com/facebook/rocksdb/pull/2144
Differential Revision: D4873732
Pulled By: lightmark
fbshipit-source-id: 81cb698106b68ef8797f564453651d50900e153a
Yanqin Jin
