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https://issues.apache.org/jira/browse/HIVE-11500?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sergey Shelukhin updated HIVE-11500:
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Description:
We need to cache file metadata (e.g. ORC file footers) for split generation
(which, on FSes that support fileId, will be valid permanently and only needs
to be removed lazily when ORC file is erased or compacted), and potentially
even some information about splits (e.g. grouping based on location that would
be good for some short time), in HBase metastore.
-It should be queryable by table. Partition predicate pushdown should be
supported. If bucket pruning is added, that too.- Given that we cannot cache
file lists (we have to check FS for new/changed files anyway), and the
difficulty of passing of data about partitions/etc. to split generation
compared to paths, we will probably just filter by paths and fileIds. It might
be different for splits
In later phases, it would be nice to save the (first category above) results of
expensive work done by jobs, e.g. data size after decompression/decoding per
column, etc. to avoid surprises when ORC encoding is very good, or very bad.
Perhaps it can even be lazily generated. Here's a pony: 🐴
was:
We need to cache file metadata (e.g. ORC file footers) for split generation
(which, on FSes that support fileId, will be valid permanently and only needs
to be removed lazily when ORC file is erased or compacted), and potentially
even some information about splits (e.g. grouping based on location that would
be good for some short time), in HBase metastore.
-It should be queryable by table. Partition predicate pushdown should be
supported. If bucket pruning is added, that too.- Given that we cannot cache
file lists (we have to check FS for new/changed files anyway), and the
difficulty of passing of data about partitions/etc. to split generation
compared to paths, we will probably just filter by fileId
In later phases, it would be nice to save the (first category above) results of
expensive work done by jobs, e.g. data size after decompression/decoding per
column, etc. to avoid surprises when ORC encoding is very good, or very bad.
Perhaps it can even be lazily generated. Here's a pony: 🐴
> implement file footer / splits cache in HBase metastore
> -------------------------------------------------------
>
> Key: HIVE-11500
> URL: https://issues.apache.org/jira/browse/HIVE-11500
> Project: Hive
> Issue Type: Sub-task
> Components: Metastore
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
>
> We need to cache file metadata (e.g. ORC file footers) for split generation
> (which, on FSes that support fileId, will be valid permanently and only needs
> to be removed lazily when ORC file is erased or compacted), and potentially
> even some information about splits (e.g. grouping based on location that
> would be good for some short time), in HBase metastore.
> -It should be queryable by table. Partition predicate pushdown should be
> supported. If bucket pruning is added, that too.- Given that we cannot cache
> file lists (we have to check FS for new/changed files anyway), and the
> difficulty of passing of data about partitions/etc. to split generation
> compared to paths, we will probably just filter by paths and fileIds. It
> might be different for splits
> In later phases, it would be nice to save the (first category above) results
> of expensive work done by jobs, e.g. data size after decompression/decoding
> per column, etc. to avoid surprises when ORC encoding is very good, or very
> bad. Perhaps it can even be lazily generated. Here's a pony: 🐴
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