Summary:
Leveldb has an api OpenForReadOnly() that opens the database
in readonly mode. This call had an option to not process the
transaction log. This patch removes this option and always
processes all transactions that had been committed. It has
been done in such a way that it does not create/write to
any new files in the process. The invariant of "no-writes"
to the leveldb data directory is still true.
This enhancement allows multiple threads to open the same database
in readonly mode and access all trancations that were committed right
upto the OpenForReadOnly call.
I changed the public API to match the new semantics because
there are no users who are currently using this api.
Test Plan: make clean check
Reviewers: sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7479
Summary: This command accepts key-value pairs from stdin with the same format of "ldb dump" command. This allows us to try out different compression algorithms/block sizes easily.
Test Plan: dump, load, dump, verify the data is the same.
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7443
Summary:
1. The OpenForReadOnly() call should not lock the db. This is useful
so that multiple processes can open the same database concurrently
for reading.
2. GetUpdatesSince should not error out if the archive directory
does not exist.
3. A new constructor for WriteBatch that can takes a serialized
string as a parameter of the constructor.
Test Plan: make clean check
Reviewers: sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7449
Summary:
Added kMetaDatabase for meta-databases in db/filename.h along with supporting
fuctions.
Fixed switch in DBImpl so that it also handles kMetaDatabase.
Fixed DestroyDB() that it can handle destroying meta-databases.
Test Plan: make check
Reviewers: sheki, emayanke, vamsi, dhruba
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D7245
Summary:
C tests would fail sometimes as DestroyDB would return a Failure Status
message when deleting an archival directory which was not created
(WAL_ttl_seconds = 0).
Fix: Ignore the Status returned on Deleting Archival Directory.
Test Plan: * make check
Reviewers: dhruba, emayanke
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7395
Summary: The old code was omitting the 0 if the char is less than 16.
Test Plan:
Tried the following program:
int main() {
unsigned char c = 1;
printf("%X\n", c);
printf("%02X\n", c);
return 0;
}
The output is:
1
01
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7437
Summary: This allows us to use ldb to do more experiments like block_size changes.
Test Plan: run it by hand.
Reviewers: dhruba, sheki, emayanke
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7431
Summary:
WriteBatch is now used by the GetUpdatesSinceAPI. This API is external
and will be used by the rocks server. Rocks Server and others will need
to know about the Sequence Number in the WriteBatch. This public method
will allow for that.
Test Plan: make all check.
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7293
Summary:
Expose the serialized string that represents a WriteBatch. This
is helpful to replicate a writebatch operation from one machine
to another.
Test Plan: make clean check
Reviewers: sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7317
Summary:
Debug and ported changes from the Open Source Github repo to our repo.
Wrote a script to easy build the java Library. future compiling java lib should just be running this script.
Test Plan: it compiles.
Reviewers: dhruba, leveldb
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D7323
Summary:
* Fixed implementation bug in Binary_Searvch introduced in https://reviews.facebook.net/D7119
* Binary search is also overflow safe.
* Delete archive log files and archive dir during DestroyDB
Test Plan: make check
Reviewers: dhruba
CC: kosievdmerwe, emayanke
Differential Revision: https://reviews.facebook.net/D7263
Summary:
Implement a interface to retrieve the most current transaction
id from the database.
Test Plan: Added unit test.
Reviewers: sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7269
Summary:
Porting various options, mostly related to Multi-threaded compaction to
Java.
Test Plan:
mvn test.
No clear plan on how else test.
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb, emayanke
Differential Revision: https://reviews.facebook.net/D7221
Summary:
filename.h has functions to do similar things.
Moving code away from db_impl.cc
Test Plan: make check
Reviewers: dhruba
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D7251
Summary:
Suppose you submit 100 background tasks one after another. The first
enqueu task finds that the queue is empty and wakes up one worker thread.
Now suppose that all remaining 99 work items are enqueued, they do not
wake up any worker threads because the queue is already non-empty.
This causes a situation when there are 99 tasks in the task queue but
only one worker thread is processing a task while the remaining
worker threads are waiting.
The fix is to always wakeup one worker thread while enqueuing a task.
I also added a check to count the number of elements in the queue
to help in debugging.
Test Plan: make clean check.
Reviewers: chip
Reviewed By: chip
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7203
Summary:
Added the following two options:
[--bloom_bits=<int,e.g.:14>]
[--compression_type=<no|snappy|zlib|bzip2>]
These options will be used when ldb opens the leveldb database.
Test Plan: Tried by hand for both success and failure cases. We do need a test framework.
Reviewers: dhruba, emayanke, sheki
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7197
Summary:
How it works:
* GetUpdatesSince takes a SequenceNumber.
* A LogFile with the first SequenceNumber nearest and lesser than the requested Sequence Number is found.
* Seek in the logFile till the requested SeqNumber is found.
* Return an iterator which contains logic to return record's one by one.
Test Plan:
* Test case included to check the good code path.
* Will update with more test-cases.
* Feedback required on test-cases.
Reviewers: dhruba, emayanke
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7119
Summary: Added 1 to indices where I shouldn't have so overrun array.
Test Plan: make check
Reviewers: sheki, emayanke, vamsi, dhruba
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D7227
Summary: Added BitStreamPutInt() and BitStreamGetInt() which take a stream of chars and can write integers of arbitrary bit sizes to that stream at arbitrary positions. There are also convenience versions of these functions that take std::strings and leveldb::Slices.
Test Plan: make check
Reviewers: sheki, vamsi, dhruba, emayanke
Reviewed By: vamsi
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7071
Summary:
A compaction is picked based on its score. It is useful to
print the compaction score in the LOG because it aids in
debugging. If one looks at the logs, one can find out why
a compaction was preferred over another.
Test Plan: make clean check
Differential Revision: https://reviews.facebook.net/D7137
Summary:
Create a directory "archive" in the DB directory.
During DeleteObsolteFiles move the WAL files (*.log) to the Archive directory,
instead of deleting.
Test Plan: Created a DB using DB_Bench. Reopened it. Checked if files move.
Reviewers: dhruba
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D6975
Summary:
Scripted and removed all trailing spaces and converted all tabs to
spaces.
Also fixed other lint errors.
All lint errors from this point of time should be taken seriously.
Test Plan: make all check
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D7059
Summary:
LevelDB should delete almost-new keys when a long-open snapshot exists.
The previous behavior is to keep all versions that were created after the
oldest open snapshot. This can lead to database size bloat for
high-update workloads when there are long-open snapshots and long-open
snapshot will be used for logical backup. By "almost new" I mean that the
key was updated more than once after the oldest snapshot.
If there were two snapshots with seq numbers s1 and s2 (s1 < s2), and if
we find two instances of the same key k1 that lie entirely within s1 and
s2 (i.e. s1 < k1 < s2), then the earlier version
of k1 can be safely deleted because that version is not visible in any snapshot.
Test Plan:
unit test attached
make clean check
Differential Revision: https://reviews.facebook.net/D6999
Summary:
Print out status at the end of a compaction run. This helps in
debugging.
Test Plan: make clean check
Reviewers: sheki
Reviewed By: sheki
Differential Revision: https://reviews.facebook.net/D7035
Summary:
When we expand the range of keys for a level 0 compaction, we
need to invoke ParentFilesInCompaction() only once for the
entire range of keys that is being compacted. We were invoking
it for each file that was being compacted, but this triggers
an assertion because each file's range were contiguous but
non-overlapping.
I renamed ParentFilesInCompaction to ParentRangeInCompaction
to adequately represent that it is the range-of-keys and
not individual files that we compact in a single compaction run.
Here is the assertion that is fixed by this patch.
db_test: db/version_set.cc:585: void leveldb::Version::ExtendOverlappingInputs(int, const leveldb::Slice&, const leveldb::Slice&, std::vector<leveldb::FileMetaData*, std::allocator<leveldb::FileMetaData*> >*, int): Assertion `user_cmp->Compare(flimit, user_begin) >= 0' failed.
Test Plan: make clean check OPT=-g
Reviewers: sheki
Reviewed By: sheki
CC: MarkCallaghan, emayanke, leveldb
Differential Revision: https://reviews.facebook.net/D6963
Summary:
On fast filesystems (e.g. /dev/shm and ext4), the flushing
of memstore to disk was fast and quick, and the background compaction
thread was not getting scheduled fast enough to delete obsolete
files before the db was closed. This caused the repair method
to pick up those files that were not part of the db and the unit
test was failing.
The fix is to enhance the unti test to run a compaction before
closing the database so that all files that are not part of the
database are truly deleted from the filesystem.
Test Plan: make c_test; ./c_test
Reviewers: chip, emayanke, sheki
Reviewed By: chip
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6915
Summary:
It would appear our unit tests make use of code from ldb_cmd,
and don't always require a valid database handle. D6855 was not aware
db_ could sometimes be NULL for such commands, and so it broke
reduce_levels_test.
This moves the check elsewhere to (at least) fix the 'ldb dump' case of
segfaulting when it couldn't open a database.
Test Plan: make check
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6903
Summary:
Link statically against snappy, using the gvfs one for facebook
environments, and the bundled one otherwise.
In addition, fix a few minor segfaults in ldb when it couldn't open the
database, and update .gitignore to include a few other build artifacts.
Test Plan: make check
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6855
Summary:
The compaction process takes some files from LevelK and
merges it into LevelK+1. The number of files it picks from
LevelK was capped such a way that the total amount of
data picked does not exceed the maxfilesize of that level.
This essentially meant that only one file from LevelK
is picked for a single compaction.
For bulkloads, we would like to take many many file from
LevelK and compact them using a single compaction run.
This patch introduces a option called the 'source_compaction_factor'
(similar to expanded_compaction_factor). It is a multiplier
that is multiplied by the maxfilesize of that level to arrive
at the limit that is used to throttle the number of source
files from LevelK. For bulk loads, set source_compaction_factor
to a very high number so that multiple files from the same
level are picked for compaction in a single compaction.
The default value of source_compaction_factor is 1, so that
we can keep backward compatibilty with existing compaction semantics.
Test Plan: make clean check
Reviewers: emayanke, sheki
Reviewed By: emayanke
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6867
Summary:
This option is needed for fast bulk uploads. The goal is to load
all the data into files in L0 without any interference from
background compactions.
Test Plan: make clean check
Reviewers: sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6849
Summary:
The method Finalize() recomputes the compaction score of each
level and then sorts these score from largest to smallest. The
idea is that the level with the largest compaction score will
be a better candidate for compaction. There are usually very
few levels, and a bubble sort code was used to sort these
compaction scores. There existed a bug in the sorting code that
skipped looking at the score for the n-1 level. This meant that
even if the compaction score of the n-1 level is large, it will
not be picked for compaction.
This patch fixes the bug and also introduces "asserts" in the
code to detect any possible inconsistencies caused by future bugs.
This bug existed in the very first code change that introduced
multi-threaded compaction to the leveldb code. That version of
code was committed on Oct 19th via
1ca0584345
Test Plan: make clean check OPT=-g
Reviewers: emayanke, sheki, MarkCallaghan
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6837
Summary:
The manifest file contains a series of edits. If the verbose
option is switched on, then print each individual edit in the
manifest file. This helps in debugging.
Test Plan: make clean manifest_dump
Reviewers: emayanke, sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6807
Summary:
StringStream.clear() does not clear the stream. It sets some flags.
Who knew? Fixing that is not printing the stuff again and again.
Test Plan: ran it on a local db
Reviewers: dhruba, emayanke
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D6795
Summary: The new function MinLevelToCompress in db_test.cc was incomplete. It needs to tell the calling function-TEST whether the test has to be skipped or not
Test Plan: make all;./db_test
Reviewers: dhruba, heyongqiang
Reviewed By: dhruba
CC: sheki
Differential Revision: https://reviews.facebook.net/D6771
Summary:
The manifest file contains a series of edits. If the verbose
option is switched on, then print each individual edit in the
manifest file. This helps in debugging.
Test Plan: make clean manifest_dump
Reviewers: emayanke, sheki
Reviewed By: sheki
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6807
Summary:
StringStream.clear() does not clear the stream. It sets some flags.
Who knew? Fixing that is not printing the stuff again and again.
Test Plan: ran it on a local db
Reviewers: dhruba, emayanke
Reviewed By: dhruba
Differential Revision: https://reviews.facebook.net/D6795
Summary:
dbstress has an option to reopen the database. Make it such that the
previous handle is not closed before we reopen, this simulates a
situation similar to a process crash.
Added new api to DMImpl to remove the lock file.
Test Plan: run db_stress
Reviewers: emayanke
Reviewed By: emayanke
CC: leveldb
Differential Revision: https://reviews.facebook.net/D6777
