[
https://issues.apache.org/jira/browse/HIVE-15335?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15765383#comment-15765383
]
Matt McCline commented on HIVE-15335:
-------------------------------------
The HiveDecimal and HiveDecimalWritable support *all* the V1 public methods and
fields. V2 for both adds a bunch of new methods and a few new fields. Some V2
methods provide faster ways to do things than V1. For example,
LazySimpleSerializeWrite uses a V2 scratch byte array method toBytes to
generate the display decimal into and then writes the scratch byte array. The
V1 logic created a throw away String, called getBytes which allocated another
throw away object, and wrote the bytes.
TestHiveDecimal's primary test philosophy is too create the HiveDecimalV1 and
HiveDecimal objects with the same input (e.g. a String, BigDecimal, etc), do
the same operation on both and compare the V1 and V2 decimals.
HiveDecimalWritableV1 and HiveDecimalWritable support all V1 public methods,
too.
One of the major performance improvements was doing operations like the new
mutateAdd directly on the HiveDecimalWritable for sum instead of calling
getHiveDecimal(), doing an add which creates another object, and then setting
the HiveDecimalWritable with the result.
> Fast Decimal
> ------------
>
> Key: HIVE-15335
> URL: https://issues.apache.org/jira/browse/HIVE-15335
> Project: Hive
> Issue Type: Bug
> Components: Hive
> Reporter: Matt McCline
> Assignee: Matt McCline
> Priority: Critical
> Attachments: HIVE-15335.01.patch, HIVE-15335.02.patch,
> HIVE-15335.03.patch, HIVE-15335.04.patch, HIVE-15335.05.patch,
> HIVE-15335.06.patch, HIVE-15335.07.patch, HIVE-15335.08.patch,
> HIVE-15335.09.patch, HIVE-15335.091.patch, HIVE-15335.092.patch,
> HIVE-15335.093.patch, HIVE-15335.094.patch, HIVE-15335.095.patch,
> HIVE-15335.096.patch, HIVE-15335.097.patch, HIVE-15335.098.patch,
> HIVE-15335.099.patch
>
>
> Replace HiveDecimal implementation that currently represents the decimal
> internally as a BigDecimal with a faster version that does not allocate extra
> objects
> Replace HiveDecimalWritable implementation with a faster version that has new
> mutable* calls (e.g. mutableAdd, mutableEnforcePrecisionScale, etc) and
> stores the result as a fast decimal instead of a slow byte array containing a
> serialized BigInteger.
> Provide faster ways to serialize/deserialize decimals.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
