[
https://issues.apache.org/jira/browse/HBASE-15477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15202361#comment-15202361
]
stack commented on HBASE-15477:
-------------------------------
RB won't let me update. The difference from RB is adding to FileContextBuilder
a constructor that takes a FileContext so I can make new context based off a
previous changing just the few items I want to change rather than have to copy
all. This fixed unit tests (was using the checksum type from default
filecontext rather than the one gotten from the block read from hdfs/cache).
> Do not save 'next block header' when we cache hfileblocks
> ---------------------------------------------------------
>
> Key: HBASE-15477
> URL: https://issues.apache.org/jira/browse/HBASE-15477
> Project: HBase
> Issue Type: Sub-task
> Components: BlockCache, Performance
> Reporter: stack
> Assignee: stack
> Attachments: 15366v4.patch, 15477.patch, 15477v2.patch, 15477v3.patch
>
>
> When we read from HDFS, we overread to pick up the next blocks header.
> Doing this saves a seek as we move through the hfile; we save having to
> do an explicit seek just to read the block header every time we need to
> read the body. We used to read in the next header as part of the
> current blocks buffer. This buffer was then what got persisted to
> blockcache; so we were over-persisting wrtiting out our block plus the
> next blocks' header (overpersisting 33 bytes). Parse of HFileBlock
> complicated by this extra tail. Fix.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
