sdong c7742452eb Add Statistics.getHistogramString() to print more detailed outputs of a histogram
Summary:
Provide a way for users to know more detailed ditribution of a histogram metrics. Example outputs:

Manually add statement
  fprintf(stdout, "%s\n", dbstats->getHistogramString(SST_READ_MICROS).c_str());
Will print out something like:

Count: 989151  Average: 1.7659  StdDev: 1.52
Min: 0.0000  Median: 1.2071  Max: 860.0000
Percentiles: P50: 1.21 P75: 1.70 P99: 5.12 P99.9: 13.67 P99.99: 21.70
------------------------------------------------------
[       0,       1 )   390839  39.513%  39.513% ########
[       1,       2 )   500918  50.641%  90.154% ##########
[       2,       3 )    79358   8.023%  98.177% ##
[       3,       4 )     6297   0.637%  98.813%
[       4,       5 )     1712   0.173%  98.986%
[       5,       6 )     1134   0.115%  99.101%
[       6,       7 )     1222   0.124%  99.224%
[       7,       8 )     1529   0.155%  99.379%
[       8,       9 )     1264   0.128%  99.507%
[       9,      10 )      988   0.100%  99.607%
[      10,      12 )     1378   0.139%  99.746%
[      12,      14 )     1828   0.185%  99.931%
[      14,      16 )      410   0.041%  99.972%
[      16,      18 )       72   0.007%  99.980%
[      18,      20 )       67   0.007%  99.986%
[      20,      25 )      106   0.011%  99.997%
[      25,      30 )       24   0.002%  99.999%
[      30,      35 )        1   0.000% 100.000%
[     250,     300 )        2   0.000% 100.000%
[     300,     350 )        1   0.000% 100.000%
[     800,     900 )        1   0.000% 100.000%

Test Plan: Manually add a print in db_bench and make sure it prints out as expected. Will add some codes to cover the function

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43611
2015-08-05 20:05:56 -07:00
2014-11-03 14:53:00 -08:00
2014-06-20 10:23:02 +02:00
2015-07-20 17:20:40 -07:00
2015-08-04 18:12:58 -07:00
2015-07-22 14:36:43 -07:00
2015-08-05 07:33:27 -07:00
2015-08-05 16:16:46 -07:00
2015-04-07 11:56:29 -07:00
2015-07-01 16:13:56 -07:00
2014-09-29 10:52:18 -07:00
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2015-04-13 10:33:43 +01:00
2015-05-29 14:36:35 -07:00
2015-08-05 16:16:46 -07:00
2015-02-26 15:19:17 -08:00

RocksDB: A Persistent Key-Value Store for Flash and RAM Storage

Build Status

RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)

This code is a library that forms the core building block for a fast key value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it specially suitable for storing multiple terabytes of data in a single database.

Start with example usage here: https://github.com/facebook/rocksdb/tree/master/examples

See the github wiki for more explanation.

The public interface is in include/. Callers should not include or rely on the details of any other header files in this package. Those internal APIs may be changed without warning.

Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/

Description
A library that provides an embeddable, persistent key-value store for fast storage.
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