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https://issues.apache.org/jira/browse/HBASE-2055?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12794366#action_12794366
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Andrew Purtell commented on HBASE-2055:
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Sorry, above I meant SYNC_INTERVAL, not SYNC_SIZE. Also it looks like the
DataFileWriter as implemented for AVRO-160 will hold up to SYNC_INTERVAL bytes
in a buffer before writing out the block. We want to hsync after a group of
related commits in the WAL whether SYNC_INTERVAL is reached or not, but also
have the stream marked with a sync marker at each SYNC_INTERVAL. This is
basically what my v3 or v4 patch does. It also writes a copy of the schema just
after the sync marker so we have an opportunity to resynchronize a reader on
each block regardless of how many previous blocks are corrupt (perhaps all).
> Serialize WAL as Avro records
> -----------------------------
>
> Key: HBASE-2055
> URL: https://issues.apache.org/jira/browse/HBASE-2055
> Project: Hadoop HBase
> Issue Type: Improvement
> Reporter: Andrew Purtell
> Priority: Minor
> Attachments: HBASE-2055-v2.patch, HBASE-2055-v3.patch,
> HBASE-2055-v4.patch, HBASE-2055.patch, jackson-core-asl-1.0.1.jar,
> jackson-mapper-asl-1.0.1.jar, paranamer-1.5.jar,
> TEST-org.apache.hadoop.hbase.regionserver.wal.TestHLog.txt.gz,
> TEST-org.apache.hadoop.hbase.regionserver.wal.TestLogRolling.txt.gz,
> TEST-org.apache.hadoop.hbase.TestFullLogReconstruction.txt.gz, test-site.patch
>
>
> There was some advocacy of using Avro for serialization of HBase WAL records
> up on hbase-...@. Idea is Hadoop core is getting away from Writables and Avro
> is the blessed replacement.
> I think we have this criteria for its use:
> 1) Performance of writing Avro records is no worse than that for writing
> Writables into a SequenceFile.
> 2) Space consumed by Avro serialization is no worse than that of Writables
> 3) File format is amenable to appends (cannot require valid trailers, etc.)
> I'll put up a patch so we can try it out.
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