HBase：配置MOB緩存

配置MOB緩存

因?yàn)榭梢噪S時(shí)存在大量MOB文件，與HFiles的數(shù)量相比，MOB文件并不總是保持打開狀態(tài)。MOB文件讀取器緩存是一個(gè)LRU緩存，它保持最近使用的MOB文件打開。要在每個(gè)RegionServer上配置MOB文件讀取器的緩存，請將以下屬性添加到R??egionServer的hbase-site.xml中，根據(jù)您的環(huán)境自定義配置，然后重新啟動(dòng)或滾動(dòng)重新啟動(dòng)RegionServer。

MOB緩存配置示例：

<property>
    <name>hbase.mob.file.cache.size</name>
    <value>1000</value>
    <description>
      Number of opened file handlers to cache.
      A larger value will benefit reads by providing more file handlers per mob
      file cache and would reduce frequent file opening and closing.
      However, if this is set too high, this could lead to a "too many opened file handers"
      The default value is 1000.
    </description>
</property>
<property>
    <name>hbase.mob.cache.evict.period</name>
    <value>3600</value>
    <description>
      The amount of time in seconds after which an unused file is evicted from the
      MOB cache. The default value is 3600 seconds.
    </description>
</property>
<property>
    <name>hbase.mob.cache.evict.remain.ratio</name>
    <value>0.5f</value>
    <description>
      A multiplier (between 0.0 and 1.0), which determines how many files remain cached
      after the threshold of files that remains cached after a cache eviction occurs
      which is triggered by reaching the `hbase.mob.file.cache.size` threshold.
      The default value is 0.5f, which means that half the files (the least-recently-used
      ones) are evicted.
    </description>
</property>