[jira] [Closed] (ORC-992) Reached max repeat length, we can directly decide to use DELTA encoding

["William Hyun (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ORC-992?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

William Hyun closed ORC-992.
----------------------------

> Reached max repeat length, we can directly decide to use DELTA encoding
> -----------------------------------------------------------------------
>
>                 Key: ORC-992
>                 URL: https://issues.apache.org/jira/browse/ORC-992
>             Project: ORC
>          Issue Type: Improvement
>          Components: Java
>    Affects Versions: 1.8.0
>            Reporter: Yiqun Zhang
>            Assignee: Yiqun Zhang
>            Priority: Minor
>             Fix For: 1.8.0
>
>
> Reached max repeat length, we can directly decide to use DELTA encoding.
> RunLengthIntegerWriterV2.java  756-760
> {code:java}
>           // if fixed runs reached max repeat length then write values
>           if (fixedRunLength == MAX_SCOPE) {
>             determineEncoding();
>             writeValues();
>           }
> {code}
> If fixed runs reached max repeat length. We have been able to determine the use of the DELTA code, fixedDelta is zero. 
> The computeZigZagLiterals, zzBits100p, and determine isFixedDelta within the determineEncoding method are all redundant in the current case.
> Similar practices.
> RunLengthIntegerWriterV2.java  767-775
> {code:java}
>           if (fixedRunLength >= MIN_REPEAT) {
>             if (fixedRunLength <= MAX_SHORT_REPEAT_LENGTH) {
>               encoding = EncodingType.SHORT_REPEAT;
>             } else {
>               encoding = EncodingType.DELTA;
>               isFixedDelta = true;
>             }
>             writeValues();
>           }
> {code}



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