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

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.5.0
• Component/s: meta, Performance
• Hadoop Flags: Reviewed

Release Note

Enables ROW_INDEX_V1 encoding on hbase:meta by default. Also enables blooms.

Will NOT enable encoding and blooms on upgrade. Operator will need to do this manually by editing hbase:meta schema (Or we provide a migration script to enable these configs -- out-of-scope for this JIRA).

• Assignee: Andrew Kyle Purtell
• Reporter: Michael Stack
• Created: 16/Aug/18 09:49
• Updated: 01/Sep/22 10:57
• Resolved: 23/Mar/22 23:30

Description

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:

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

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:

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,

Issue Links

• is related to: HBASE-23705 Add CellComparator to HFileContext
• is related to: HBASE-23279 Switch default block encoding to ROW_INDEX_V1
• is related to: HBASE-23055 Alter hbase:meta
• links to: GitHub Pull Request #1012
• links to: GitHub Pull Request #4268

Sub-Tasks

• Add CellComparator to HFileContext: Resolved