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https://issues.apache.org/jira/browse/HADOOP-3315?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Owen O'Malley updated HADOOP-3315:
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Description: SequenceFile's block compression format is too complex and
requires 4 codecs to compress or decompress. It would be good to have a file
format that only needs (was: SequenceFile's block compression format is too
complex and requires 4 codecs to compress or decompress. I would propose that
we move to:
{code}
block 1
block 2
...
index
tail
{code}
where block is compressed, and contain:
{code}
key/value1: key len (vint), key, value len (vint), value
key/value 2
...
{code}
The index would be compressed and contain:
{code}
block 1: offset, first record idx
block 2: offset, first record idx
block 3: offset, first record idx:
...
{code}
and the tail would look like:
{code}
key class name
value class name
index kind (none, keys, keys+bloom filter)
format version
offset of tail
offset of index
{code}
Then extensions of this format would put more indexes between the last block
and the start of the index. So for example, the first key of each block:
{code}
first key of block 1: key len (vint), key
first key of block 2
...
offset of start key index
{code}
Another reasonable extension of the key index would be a bloom filter of the
keys:
{code}
bloom filter serialization
offset of bloom filter index start
{code}
)
I would propose that we move to:
{code}
block 1
block 2
...
index
tail
{code}
where block is compressed, and contain:
{code}
key/value1: key len (vint), key, value len (vint), value
key/value 2
...
{code}
The index would be compressed and contain:
{code}
block 1: offset, first record idx
block 2: offset, first record idx
block 3: offset, first record idx:
...
{code}
and the tail would look like:
{code}
key class name
value class name
index kind (none, keys, keys+bloom filter)
format version
offset of tail
offset of index
{code}
Then extensions of this format would put more indexes between the last block
and the start of the index. So for example, the first key of each block:
{code}
first key of block 1: key len (vint), key
first key of block 2
...
offset of start key index
{code}
Another reasonable extension of the key index would be a bloom filter of the
keys:
{code}
bloom filter serialization
offset of bloom filter index start
{code}
> New binary file format
> ----------------------
>
> Key: HADOOP-3315
> URL: https://issues.apache.org/jira/browse/HADOOP-3315
> Project: Hadoop Core
> Issue Type: New Feature
> Components: io
> Reporter: Owen O'Malley
>
> SequenceFile's block compression format is too complex and requires 4 codecs
> to compress or decompress. It would be good to have a file format that only
> needs
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