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From "Qian Xu (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (SQOOP-1968) Optimize schema operation in getMatchingData of NameMatcher
Date Tue, 06 Jan 2015 12:37:34 GMT

     [ https://issues.apache.org/jira/browse/SQOOP-1968?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Qian Xu updated SQOOP-1968:
---------------------------
    Attachment: SQOOP-1968.2.patch

Thanks [~jarcec] (1) Removed unused imports (2) Uses proper method names (3) RB is still unable
to upload

> Optimize schema operation in getMatchingData of NameMatcher
> -----------------------------------------------------------
>
>                 Key: SQOOP-1968
>                 URL: https://issues.apache.org/jira/browse/SQOOP-1968
>             Project: Sqoop
>          Issue Type: Improvement
>          Components: connectors/generic
>    Affects Versions: 2.0.0
>            Reporter: Jerry Chen
>            Assignee: Qian Xu
>         Attachments: SQOOP-1968.2.patch, SQOOP-1968.patch
>
>
> Two performance issues found in the Matcher implementations.
> 1. In getMatchingData  of NameMatcher, the following code block of building a HashMap
will not change across different getMatchingData  calls. The HashMap can build only once in
Constructor.
> {code}
> HashMap<String,Column> colNames = new HashMap<String, Column>();
> for (Column fromCol: getFromSchema().getColumnsArray()) {
>   colNames.put(fromCol.getName(), fromCol);
> }
> {code}
> 2. In getMatchingData  of NameMatcher, indexOf of a List implementation is not efficient.
It usually involves a loop for finding the object and return the index. To improve, we can
simple store the index in the above HashMap and retrieve the index by HashMap lookup directly
> {code}
> int fromIndex = getFromSchema().getColumnsList().indexOf(fromCol);
> {code}
> These performance problems are critical because getMatchingData is repeatedly calling
for each record.



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