[jira] [Created] (HBASE-21065) Try ROW_INDEX_V1 encoding on meta table (fix bloomfilters on meta while we are at it)

["stack (JIRA)" <ji...@apache.org>]

stack created HBASE-21065:
-----------------------------

             Summary: Try ROW_INDEX_V1 encoding on meta table (fix bloomfilters on meta while we are at it)
                 Key: HBASE-21065
                 URL: https://issues.apache.org/jira/browse/HBASE-21065
             Project: HBase
          Issue Type: Improvement
          Components: meta, Performance
            Reporter: stack
            Assignee: stack


Some users end up hitting meta hard. Bulk is probably because our client goes to meta too often, and the real 'fix' for a saturated meta is splitting it, but the encoding that came in with HBASE-16213, ROW_INDEX_V1, could help in the near term. It adds an index on hfile blocks and helped improve random reads against user-space tables (less compares as we used index to go direct to requested Cells rather than look at each Cell in turn until we found what we wanted -- see RN on HBASE-16213 for citation).

I also noticed code-reading that we don't enable blooms on hbase:meta tables; that could save some CPU and speed things up a bit too:

{code}
        // Disable blooms for meta.  Needs work.  Seems to mess w/ getClosestOrBefore.
        .setBloomFilterType(BloomType.NONE)
{code}

This issue is about doing a bit of perf compare of encoding *on* vs current default (and will check diff in size of indexed blocks).

Meta access is mostly random-read I believe (A review of a user's access showed this so at least for their workload). The nice addition, HBASE-19722 Meta query statistics metrics source, would help verify if it saw some usage on a prod cluster.

If all is good, I'd like to make a small patch, one that could be easily backported, with minimal changes in it.

As is, its all a little awkward as the meta table schema is hard-coded and meta is immutable -- stuff we'll have to fix if we want to split meta -- so in the meantime it requires a code change to enable (and a backport of HBASE-16213 -- this patch is in 1.4.0 only currently, perhaps that is enough). Code change to enable is small:

{code}
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/util/FSTableDescriptors.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/util/FSTableDescriptors.java
index 28c7ec3c2f..8f08f94dc1 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/util/FSTableDescriptors.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/util/FSTableDescriptors.java
@@ -160,6 +160,7 @@ public class FSTableDescriptors implements TableDescriptors {
         .setScope(HConstants.REPLICATION_SCOPE_LOCAL)
         // Disable blooms for meta.  Needs work.  Seems to mess w/ getClosestOrBefore.
         .setBloomFilterType(BloomType.NONE)
+        .setDataBlockEncoding(org.apache.hadoop.hbase.io.encoding.DataBlockEncoding.ROW_INDEX_V1)
         .build())
       .setColumnFamily(ColumnFamilyDescriptorBuilder.newBuilder(HConstants.TABLE_FAMILY)
         .setMaxVersions(conf.getInt(HConstants.HBASE_META_VERSIONS,
{code}





--
This message was sent by Atlassian JIRA
(v7.6.3#76005)