andreacavalli/rocksdb
0
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Merge branch 'master' into columnfamilies

Browse Source
This commit is contained in:
Igor Canadi 2014-02-07 14:40:35 -08:00
commit 9ff9abeb83
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
doc/index.html
View File

@ -609,13 +609,13 @@ key-value during background compaction.
</ul>
<p>
Other options impacting performance of compactions and when they get triggered
are:
are:
<ul>
<p>
<li> <code>Options::access_hint_on_compaction_start</code> - Specify the file access
<li> <code>Options::access_hint_on_compaction_start</code> - Specify the file access
pattern once a compaction is started. It will be applied to all input files of a compaction. Default: NORMAL
<p>
<li> <code>Options::level0_file_num_compaction_trigger</code> - Number of files to trigger level-0 compaction.
<li> <code>Options::level0_file_num_compaction_trigger</code> - Number of files to trigger level-0 compaction.
A negative value means that level-0 compaction will not be triggered by number of files at all.
<p>
<li> <code>Options::max_mem_compaction_level</code> - Maximum level to which a new compacted memtable is pushed if it
@ -623,7 +623,7 @@ does not create overlap. We try to push to level 2 to avoid the relatively expe
expensive manifest file operations. We do not push all the way to the largest level since that can generate a lot of wasted disk
space if the same key space is being repeatedly overwritten.
<p>
<li> <code>Options::target_file_size_base</code> and <code>Options::target_file_size_multiplier</code> -
<li> <code>Options::target_file_size_base</code> and <code>Options::target_file_size_multiplier</code> -
Target file size for compaction. target_file_size_base is per-file size for level-1.
Target file size for level L can be calculated by target_file_size_base * (target_file_size_multiplier ^ (L-1))
For example, if target_file_size_base is 2MB and target_file_size_multiplier is 10, then each file on level-1 will
@ -698,7 +698,7 @@ Default: kCompactionStopStyleTotalSize
A thread pool is associated with Env environment object. The client has to create a thread pool by setting the number of background
threads using method <code>Env::SetBackgroundThreads()</code> defined in <code>rocksdb/env.h</code>.
We use the thread pool for compactions and memtable flushes.
Since memtable flushes are in critical code path (stalling memtable flush can stall writes, increasing p99), we suggest
Since memtable flushes are in critical code path (stalling memtable flush can stall writes, increasing p99), we suggest
having two thread pools - with priorities HIGH and LOW. Memtable flushes can be set up to be scheduled on HIGH thread pool.
There are two options available for configuration of background compactions and flushes:
<ul>
@ -779,9 +779,9 @@ implementation. See <code>rocksdb/util/env_posix.h</code> for an example.
<p>
To be able to efficiently tune your application, it is always helpful if you
have access to usage statistics. You can collect those statistics by setting
<code>Options::table_stats_collectors</code> or
<code>Options::table_properties_collectors</code> or
<code>Options::statistics</code>. For more information, refer to
<code>rocksdb/table_stats.h</code> and <code>rocksdb/statistics.h</code>.
<code>rocksdb/table_properties.h</code> and <code>rocksdb/statistics.h</code>.
These should not add significant overhead to your application and we
recommend exporting them to other monitoring tools.