Summary:
Add `num_levels`, `is_bottommost`, and table file creation
`reason` to `FilterBuildingContext`, in anticipation of more powerful
Bloom-like filter support.
To support this, added `is_bottommost` and `reason` to
`TableBuilderOptions`, which allowed removing `reason` parameter from
`rocksdb::BuildTable`.
I attempted to remove `skip_filters` from `TableBuilderOptions`, because
filter construction decisions should arise from options, not one-off
parameters. I could not completely remove it because the public API for
SstFileWriter takes a `skip_filters` parameter, and translating this
into an option change would mean awkwardly replacing the table_factory
if it is BlockBasedTableFactory with new filter_policy=nullptr option.
I marked this public skip_filters option as deprecated because of this
oddity. (skip_filters on the read side probably makes sense.)
At least `skip_filters` is now largely hidden for users of
`TableBuilderOptions` and is no longer used for implementing the
optimize_filters_for_hits option. Bringing the logic for that option
closer to handling of FilterBuildingContext makes it more obvious that
hese two are using the same notion of "bottommost." (Planned:
configuration options for Bloom-like filters that generalize
`optimize_filters_for_hits`)
Recommended follow-up: Try to get away from "bottommost level" naming of
things, which is inaccurate (see
VersionStorageInfo::RangeMightExistAfterSortedRun), and move to
"bottommost run" or just "bottommost."
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8246
Test Plan:
extended an existing unit test to exercise and check various
filter building contexts. Also, existing tests for
optimize_filters_for_hits validate some of the "bottommost" handling,
which is now closely connected to FilterBuildingContext::is_bottommost
through TableBuilderOptions::is_bottommost
Reviewed By: mrambacher
Differential Revision: D28099346
Pulled By: pdillinger
fbshipit-source-id: 2c1072e29c24d4ac404c761a7b7663292372600a
main
Peter Dillinger4 years agocommitted byFacebook GitHub Bot
* Add new option allow_stall passed during instance creation of WriteBufferManager. When allow_stall is set, WriteBufferManager will stall all writers shared across multiple DBs and columns if memory usage goes beyond specified WriteBufferManager::buffer_size (soft limit). Stall will be cleared when memory is freed after flush and memory usage goes down below buffer_size.
* Add new option allow_stall passed during instance creation of WriteBufferManager. When allow_stall is set, WriteBufferManager will stall all writers shared across multiple DBs and columns if memory usage goes beyond specified WriteBufferManager::buffer_size (soft limit). Stall will be cleared when memory is freed after flush and memory usage goes down below buffer_size.
* Added more fields to FilterBuildingContext with LSM details, for custom filter policies that vary behavior based on where they are in the LSM-tree.
### Performace Improvements
### Performace Improvements
* BlockPrefetcher is used by iterators to prefetch data if they anticipate more data to be used in future. It is enabled implicitly by rocksdb. Added change to take in account read pattern if reads are sequential. This would disable prefetching for random reads in MultiGet and iterators as readahead_size is increased exponential doing large prefetches.
* BlockPrefetcher is used by iterators to prefetch data if they anticipate more data to be used in future. It is enabled implicitly by rocksdb. Added change to take in account read pattern if reads are sequential. This would disable prefetching for random reads in MultiGet and iterators as readahead_size is increased exponential doing large prefetches.
### Public API change
### Public API change
* Removed a parameter from TableFactory::NewTableBuilder, which should not be called by user code because TableBuilder is not a public API.
* Removed a parameter from TableFactory::NewTableBuilder, which should not be called by user code because TableBuilder is not a public API.
* The `skip_filters` parameter to SstFileWriter is now considered deprecated. Use `BlockBasedTableOptions::filter_policy` to control generation of filters.