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From 谢良 <xieli...@xiaomi.com>
Subject 答复: one table flushes at much smaller sizes than other?
Date Fri, 27 Dec 2013 03:51:01 GMT
Do you observe some log like "Too many hlogs" before flushing a few
dozen KB log ?  Just want to double-check it's weather a forcing flush issue
or not:)

Thanks,
Liang
________________________________________
发件人: Norbert Burger [norbert.burger@gmail.com]
发送时间: 2013年12月27日 5:52
收件人: user@hbase.apache.org
主题: one table flushes at much smaller sizes than other?

Hi folks, we're currently running CDH4.1.2 (HBase 0.92 + patches).

Looking through the logs, I'm seeing that some tables are flushing at much
lower size than others (a few dozen KB as opposed to the expected 128 MB).

Looking through some of great case studies like [1], [2], and [3], it's not
clear to me why this is happening.  We're using the defaults for upper,
lower limits (0.35 and 0.40, respectively), and the RS status pages show
that we're only using 25% of our memstore allocation.

Our regions/RS ratio is currently at 60-70.  We do have some other tables
online where column families are skewed heavily sizewise -- could this be
causing other tables in our cluster to flush more frequently than others?

Norbert

[1] http://blog.sematext.com/2012/07/16/hbase-memstore-what-you-should-know/
[2] http://www.ngdata.com/visualizing-hbase-flushes-and-compactions/
[3] http://gbif.blogspot.com/2012/07/optimizing-writes-in-hbase.html
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