Summary:
We have several different types of data structures for file information.
FileLevel is kinda of confusing since it only contains file range and
fd. Rename it to LevelFilesBrief to make it clear.
Unfriend CompactedDBImpl as a by product
Test Plan:
make release / make all
will run full test with all stacked diffs
Reviewers: sdong, yhchiang, rven, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D27585
Summary:
Intead of passing callback function pointer and its arg on Table::Get()
interface, passing GetContext. This makes the interface cleaner and
possible better perf. Also adding a fast pass for SaveValue()
Test Plan: make all check
Reviewers: igor, yhchiang, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D24057
Summary:
Add the MultiGet API to allow prefetching.
With file size of 1.5G, I configured it to have 0.9 hash ratio that can
fill With 115M keys and result in 2 hash functions, the lookup QPS is
~4.9M/s vs. 3M/s for Get().
It is tricky to set the parameters right. Since files size is determined
by power-of-two factor, that means # of keys is fixed in each file. With
big file size (thus smaller # of files), we will have more chance to
waste lot of space in the last file - lower space utilization as a
result. Using smaller file size can improve the situation, but that
harms lookup speed.
Test Plan: db_bench
Reviewers: yhchiang, sdong, igor
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D23673
Summary:
Add a CompactedDBImpl that will enabled when calling OpenForReadOnly()
and the DB only has one level (>0) of files. As a performan comparison,
CuckooTable performs 2.1M/s with CompactedDBImpl vs. 1.78M/s with
ReadOnlyDBImpl.
Test Plan: db_bench
Reviewers: yhchiang, igor, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D23553
