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https://issues.apache.org/jira/browse/HBASE-8496?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13694923#comment-13694923
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stack commented on HBASE-8496:
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Add author, date, and JIRA you are referring to.
Tags are going to be handled by cps and not be native? Or is thought that we
do them as CP first and then pull them native?
Why does hfile care about tags? It is not doing interpretation of the Cells it
has?
You don't want to add addTags to Mutation so you can do Put#addTags? We can do
this later I suppose.
If tags as attribute, maybe have a special key, something like,
tags.visibility... so know which attributes are for inclusion in tags.
Should you make a TaggedKeyValueCodec or you think it fine just making
KeyValueCodec handle tags if present?
So, pass a cellblock to hfile and then add codec metadata to hfile metadata?
Hmm... I suppose using a codec breaks when you get to hfile because you have to
do a kv at a time, unless you can do append(Codec). Besides, hfile is broke at
the moment in that it only knows one kind of kv serialization and it is baked
in everwhere. How you propose we fix this? Can we move hfile to be Cell based?
Is it good adding tags at end of kv? I suppose it is fine for now getting them
in. We can do an alternate serialization later, one that keeps tags close so
we can spin through them fast w/o having to read value data.
"With KeyValuecodecs in place now we would issue two reads to read the total KV
size and then read the entire byte array and then form the KVs." -- it has to
be two reads? COuld we not write the block as a KeyValueCodec? And then in
hfile metadata say what Codec class writing blocks was?
We need to change hfile so it does Cells. HFileBlockEncoders also are broke in
that they presume the KV serialization format. HFileBlockEncoders should be
like the new Cell Codecs.
You say "All the encoders will need to understand the tags." Would be best for
all if hfiles understood Cells. When you say additional 'read', do you mean a
new seek?
"...but we would not be able to use the KeyValueCodec.decoder() on the
HFileBlocks." can we not make this happen? HFileBlockEncoders are broke.
"This would involve changes to the HFileBlockHeader." Could hfile blocks be
cellblocks? And in meta data for hfile say what decoder to use?
Thanks Ram.
> Implement tags and the internals of how a tag should look like
> --------------------------------------------------------------
>
> Key: HBASE-8496
> URL: https://issues.apache.org/jira/browse/HBASE-8496
> Project: HBase
> Issue Type: New Feature
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Fix For: 0.98.0
>
> Attachments: Tag design.pdf
>
>
> The intent of this JIRA comes from HBASE-7897.
> This would help us to decide on the structure and format of how the tags
> should look like.
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