Summary:
Fixed the following compile error by replacing pow by shift, as it computes
power of 2.
util/options_builder.cc:133:14: error: no member named 'pow' in namespace 'std'
std::pow(2, std::max(0, std::min(3, level0_stop_writes_trigger -
~~~~~^
1 error generated.
make: *** [util/options_builder.o] Error 1
Test Plan: make success in mac and linux
Reviewers: ljin, igor, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D20475
Summary:
Add a function GetOptions(), where based on four parameters users give: read/write amplification threshold, memory budget for mem tables and target DB size, it picks up a compaction style and parameters for them. Background threads are not touched yet.
One limit of this algorithm: since compression rate and key/value size are hard to predict, it's hard to predict level 0 file size from write buffer size. Simply make 1:1 ratio here.
Sample results: https://reviews.facebook.net/P477
Test Plan: Will add some a unit test where some sample scenarios are given and see they pick the results that make sense
Reviewers: yhchiang, dhruba, haobo, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18741
Yueh-Hsuan Chiang