hive-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sergey Shelukhin (JIRA)" <>
Subject [jira] [Commented] (HIVE-11525) Bucket pruning
Date Fri, 14 Aug 2015 19:18:46 GMT


Sergey Shelukhin commented on HIVE-11525:

Sure! Thanks!

> Bucket pruning
> --------------
>                 Key: HIVE-11525
>                 URL:
>             Project: Hive
>          Issue Type: Improvement
>          Components: Logical Optimizer
>    Affects Versions: 0.13.0, 0.14.0, 0.13.1, 1.0.0, 1.1.0
>            Reporter: Maciek Kocon
>            Assignee: Takuya Fukudome
>              Labels: gsoc2015
> Logically and functionally bucketing and partitioning are quite similar - both provide
mechanism to segregate and separate the table's data based on its content. Thanks to that
significant further optimisations like [partition] PRUNING or [bucket] MAP JOIN are possible.
> The difference seems to be imposed by design where the PARTITIONing is open/explicit
while BUCKETing is discrete/implicit.
> Partitioning seems to be very common if not a standard feature in all current RDBMS while
BUCKETING seems to be HIVE specific only.
> In a way BUCKETING could be also called by "hashing" or simply "IMPLICIT PARTITIONING".
> Regardless of the fact that these two are recognised as two separate features available
in Hive there should be nothing to prevent leveraging same existing query/join optimisations
across the two.
> BUCKET pruning
> Enable partition PRUNING equivalent optimisation for queries on BUCKETED tables
> Simplest example is for queries like:
> "SELECT … FROM x WHERE colA=123123"
> to read only the relevant bucket file rather than all file-buckets that belong to a table.

This message was sent by Atlassian JIRA

View raw message