Summary:
Currently, the in-memory hash index of blockbased table uses a precise hash map to track the prefix to block range mapping. In some use cases, especially when prefix itself is big, the memory overhead becomes a problem. This diff introduces a fixed hash bucket array that does not store the prefix and allows prefix collision, which is similar to the plaintable hash index, in order to reduce the memory consumption.
Just a quick draft, still testing and refining.
Test Plan: unit test and shadow testing
Reviewers: dhruba, kailiu, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19047
Summary: This is a temporary solution to a issue that we have with compression libraries. See task #4453446.
Test Plan: make check doesn't complain :)
Reviewers: haobo, ljin, yhchiang, dhruba, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18975
Summary:
Materialize the hash index to avoid the soaring cpu/flash usage
when initializing the database.
Test Plan: existing unit tests passed
Reviewers: sdong, haobo
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18339
Summary:
This diff addresses task #4296714 and rethinks how users provide us with TablePropertiesCollectors as part of Options.
Here's description of task #4296714:
I'm debugging #4295529 and noticed that our count of user properties kDeletedKeys is wrong. We're sharing one single InternalKeyPropertiesCollector with all Table Builders. In LOG Files, we're outputting number of kDeletedKeys as connected with a single table, while it's actually the total count of deleted keys since creation of the DB.
For example, this table has 3155 entries and 1391828 deleted keys.
The problem with current approach that we call methods on a single TablePropertiesCollector for all the tables we create. Even worse, we could do it from multiple threads at the same time and TablePropertiesCollector has no way of knowing which table we're calling it for.
Good part: Looks like nobody inside Facebook is using Options::table_properties_collectors. This means we should be able to painfully change the API.
In this change, I introduce TablePropertiesCollectorFactory. For every table we create, we call `CreateTablePropertiesCollector`, which creates a TablePropertiesCollector for a single table. We then use it sequentially from a single thread, which means it doesn't have to be thread-safe.
Test Plan:
Added a test in table_properties_collector_test that fails on master (build two tables, assert that kDeletedKeys count is correct for the second one).
Also, all other tests
Reviewers: sdong, dhruba, haobo, kailiu
Reviewed By: kailiu
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18579
Summary:
A recent commit e37dd216f9 makes sure hash index can be used when reading existing files. This patch uses another way to achieve the approach:
(1) Currently, always writing kBinarySearch to files, despite of BlockBasedTableOptions.IndexType setting.
(2) When reading a file, read out the field, and make sure it is kBinarySearch, while always use index type by users.
The reason for doing it is, to reserve kHashSearch property on disk to future. If now we write out binary index for both of kHashSearch and kBinarySearch. We have to use a new flag in the future for hash index on disk, otherwise compatibility would break. Also, we want the real index type and type shown in properties block to be consistent.
Test Plan: make all check
Reviewers: haobo, kailiu
Reviewed By: kailiu
CC: igor, ljin, yhchiang, xjin, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D18009
Summary:
I was wrong about the "index builder", right now since we create index
by scanning both whole table and index, there is not need to preserve
the whole key as the index key.
I switch back to original way index which is both space efficient and
able to supprot in-fly construction of hash index.
IN this patch, I made minimal change since I'm not sure if we still need
the "pluggable index builder", under current circumstance it is of no use
and kind of over-engineered. But I'm not sure if we can still exploit its
usefulness in the future; otherwise I think I can just burn them with great
vengeance.
Test Plan: unit tests
Reviewers: sdong, haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17745
Summary: Based on previous patches, this diff eventually provides the end-to-end mechanism for users to specify the hash-index.
Test Plan: Wrote several new unit tests.
Reviewers: sdong, haobo, dhruba
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D16539
Summary:
This patch introduced a new table options that allows us to make
block-based table's index pluggable.
To support that new features:
* Code has been refacotred to be more flexible and supports this option well.
* More documentation is added for the existing obsecure functionalities.
* Big surgeon on DataBlockReader(), where the logic was really convoluted.
* Other small code cleanups.
The pluggablility will mostly affect development of internal modules
and won't change frequently, as a result I intentionally avoid
heavy-weight patterns (like factory) and try to make it simple.
Test Plan: make all check
Reviewers: haobo, sdong
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D16395
Summary:
Previous code is too convoluted and I must be drunk for letting
such code to be written without a second thought.
Thanks to the discussion with @sdong, I added the `Options` when
generating the flusher, thus avoiding the tricks.
Just FYI: I resisted to add Options in flush_block_policy.h since I
wanted to avoid cyclic dependencies: FlushBlockPolicy dpends on Options
and Options also depends FlushBlockPolicy... While I appreciate my
effort to prevent it, the old design turns out creating more troubles than
it tried to avoid.
Test Plan: ran ./table_test
Reviewers: sdong
Reviewed By: sdong
CC: sdong, leveldb
Differential Revision: https://reviews.facebook.net/D16503
Summary: In PlainTable, use one single byte to represent 8 bytes of internal bytes, if seqID = 0 and it is value type (which should be common for bottom most files). It is to save 7 bytes for uncompressed cases.
Test Plan: make all check
Reviewers: haobo, dhruba, kailiu
Reviewed By: haobo
CC: igor, leveldb
Differential Revision: https://reviews.facebook.net/D15489
Summary:
This is the last diff that adds the property block to plain table.
The format resembles that of the block-based table: https://github.com/facebook/rocksdb/wiki/Rocksdb-table-format
[data block]
[meta block 1: stats block]
[meta block 2: future extended block]
...
[meta block K: future extended block] (we may add more meta blocks in the future)
[metaindex block]
[index block: we only have the placeholder here, we can add persistent index block in the future]
[Footer: contains magic number, handle to metaindex block and index block]
<end_of_file>
Test Plan: extended existing property block test.
Reviewers: haobo, sdong, dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14523
Summary: This change will allow other table to reuse the code for meta blocks.
Test Plan: all existing unit tests passed
Reviewers: dhruba, haobo, sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14475
Summary:
As we are having different types of tables and they all might share the same structure in block-based table:
[metaindex block]
[index block]
[Footer]
To be able to identify differnt types of tables, we need to parameterize the "magic number" in the `Footer`.
Test Plan:
make check
Summary:
I went through all remaining shared_ptrs and removed the ones that I found not-necessary. Only GenerateCachePrefix() is called fairly often, so don't expect much perf wins.
The ones that are left are accessed infrequently and I think we're fine with keeping them.
Test Plan: make asan_check
Reviewers: dhruba, haobo
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14427
Summary: liveness of the statistics object is already ensured by the shared pointer in DB options. There's no reason to pass again shared pointer among internal functions. Raw pointer is sufficient and efficient.
Test Plan: make check
Reviewers: dhruba, MarkCallaghan, igor
Reviewed By: dhruba
CC: leveldb, reconnect.grayhat
Differential Revision: https://reviews.facebook.net/D14289
Summary:
Previously we introduce a `flush_block_policy_factory` in Options, however, that options is strongly releated to Table based tables.
It will make more sense to move it to block based table's own factory class.
Test Plan: make check to pass existing tests
Reviewers: dhruba, haobo
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14211
Summary:
The primary motivation of the changes is to make it easier to figure out the inside of the tables.
* rename "table stats" to "table properties" since now we have more than "integers" to store in the property block.
* Add filter block size to the basic table properties.
* Whenever a table is built, we'll log the table properties (the sample output is in Test Plan).
* Make an api to expose deleted keys.
Test Plan:
Passed all existing test. and the sample output of table stats:
==================================================================
Basic Properties
------------------------------------------------------------------
# data blocks: 1
# entries: 1
raw key size: 9
raw average key size: 9
raw value size: 9
raw average value size: 0
data block size: 25
index block size: 27
filter block size: 18
(estimated) table size: 70
filter policy: rocksdb.BuiltinBloomFilter
==================================================================
User collected properties: InternalKeyPropertiesCollector
------------------------------------------------------------------
kDeletedKeys: 1
==================================================================
Reviewers: dhruba, haobo
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14187
Summary:
By original design, the regular `block options` and index `block options` in table_builder is mutable. We can use ChangeOptions to change the options directly.
However, with my last change, `BlockBuilder` no longer hold the reference to the index_block_options -- as a result, any changes made after the creation of index block builder will be of no effect.
But still the code is very error-prone and developers can easily fall into the trap without aware of it. To avoid this problem from happening in the future, I deleted the `ChangeOptions` and the `index_block_options`, as well as many other changes to make it less misleading.
Test Plan:
make
make check
make release
Reviewers: dhruba, haobo
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13707
Summary: The work to make sure mac os compiles rocksdb is not completed yet. But at least we can start cleaning some warnings captured only by g++ from mac os..
Test Plan: ran make in mac os
Reviewers: dhruba
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14049
Summary: Allow block based table to configure the way flushing the blocks. This feature will allow us to add support for prefix-aligned block.
Test Plan: make check
Reviewers: dhruba, haobo, sdong, igor
Reviewed By: sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13875
Summary:
Rocksdb can now support a uncompressed block cache, or a compressed
block cache or both. Lookups first look for a block in the
uncompressed cache, if it is not found only then it is looked up
in the compressed cache. If it is found in the compressed cache,
then it is uncompressed and inserted into the uncompressed cache.
It is possible that the same block resides in the compressed cache
as well as the uncompressed cache at the same time. Both caches
have their own individual LRU policy.
Test Plan: Unit test case attached.
Reviewers: kailiu, sdong, haobo, leveldb
Reviewed By: haobo
CC: xjin, haobo
Differential Revision: https://reviews.facebook.net/D12675
Summary:
This patch is to address @haobo's comments on D13521:
1. rename Table to be TableReader and make its factory function to be GetTableReader
2. move the compression type selection logic out of TableBuilder but to compaction logic
3. more accurate comments
4. Move stat name constants into BlockBasedTable implementation.
5. remove some uncleaned codes in simple_table_db_test
Test Plan: pass test suites.
Reviewers: haobo, dhruba, kailiu
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13785
Summary: This patch makes Table and TableBuilder a abstract class and make all the implementation of the current table into BlockedBasedTable and BlockedBasedTable Builder.
Test Plan: Make db_test.cc to work with block based table. Add a new test simple_table_db_test.cc where a different simple table format is implemented.
Reviewers: dhruba, haobo, kailiu, emayanke, vamsi
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13521
