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https://issues.apache.org/jira/browse/HBASE-5778?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13532772#comment-13532772
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Ted Yu commented on HBASE-5778:
-------------------------------
Thanks for the reminder, J-D.
My question becomes: shall we introduce TestWALReplayUncompressed ?
Running the patch on Linux I got:
{code}
testSimplePutDelete(org.apache.hadoop.hbase.replication.TestMasterReplication)
Time elapsed: 0.12 sec <<< FAILURE!
java.lang.AssertionError: Waited too much time for put replication
at org.junit.Assert.fail(Assert.java:93)
at
org.apache.hadoop.hbase.replication.TestMasterReplication.putAndWait(TestMasterReplication.java:276)
at
org.apache.hadoop.hbase.replication.TestMasterReplication.testSimplePutDelete(TestMasterReplication.java:213)
queueFailover(org.apache.hadoop.hbase.replication.TestReplication) Time
elapsed: 0.119 sec <<< FAILURE!
java.lang.AssertionError: Waited too much time for queueFailover replication.
Waited 17533ms.
at org.junit.Assert.fail(Assert.java:93)
at
org.apache.hadoop.hbase.replication.TestReplication.queueFailover(TestReplication.java:765)
{code}
For ReplicationHLogReaderManager.java:
{code}
+public class ReplicationHLogReaderManager {
{code}
Please add annotation for audience and stability.
For readNextAndSetPosition():
{code}
+ * Get the next entry, returned and also added in the array
{code}
Please phase the above line so that it is easier to understand.
> Turn on WAL compression by default
> ----------------------------------
>
> Key: HBASE-5778
> URL: https://issues.apache.org/jira/browse/HBASE-5778
> Project: HBase
> Issue Type: Improvement
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.96.0
>
> Attachments: 5778.addendum, 5778-addendum.txt, HBASE-5778-0.94.patch,
> HBASE-5778-0.94-v2.patch, HBASE-5778-0.94-v3.patch, HBASE-5778-0.94-v4.patch,
> HBASE-5778-0.94-v5.patch, HBASE-5778-0.94-v6.patch, HBASE-5778.patch,
> HBASE-5778-trunk-v6.patch
>
>
> I ran some tests to verify if WAL compression should be turned on by default.
> For a use case where it's not very useful (values two order of magnitude
> bigger than the keys), the insert time wasn't different and the CPU usage 15%
> higher (150% CPU usage VS 130% when not compressing the WAL).
> When values are smaller than the keys, I saw a 38% improvement for the insert
> run time and CPU usage was 33% higher (600% CPU usage VS 450%). I'm not sure
> WAL compression accounts for all the additional CPU usage, it might just be
> that we're able to insert faster and we spend more time in the MemStore per
> second (because our MemStores are bad when they contain tens of thousands of
> values).
> Those are two extremes, but it shows that for the price of some CPU we can
> save a lot. My machines have 2 quads with HT, so I still had a lot of idle
> CPUs.
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