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From "Jerry Chen (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (SQOOP-1968) Optimize schema operation in getMatchingData of NameMatcher
Date Mon, 05 Jan 2015 08:25:35 GMT

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

Jerry Chen updated SQOOP-1968:
------------------------------
    Description: 
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.
bq.
    HashMap<String,Column> colNames = new HashMap<String, Column>();

    for (Column fromCol: getFromSchema().getColumnsArray()) {
      colNames.put(fromCol.getName(), fromCol);
    }

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

{color:red}
int fromIndex = getFromSchema().getColumnsList().indexOf(fromCol);
{color}
These performance problems are critical because getMatchingData is repeatedly calling for
each record.

  was:
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.
{color:red}
    HashMap<String,Column> colNames = new HashMap<String, Column>();

    for (Column fromCol: getFromSchema().getColumnsArray()) {
      colNames.put(fromCol.getName(), fromCol);
    }
{color}
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

{color:red}
int fromIndex = getFromSchema().getColumnsList().indexOf(fromCol);
{color}
These performance problems are critical because getMatchingData is repeatedly calling for
each record.


> 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
>
> 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.
> bq.
>     HashMap<String,Column> colNames = new HashMap<String, Column>();
>     for (Column fromCol: getFromSchema().getColumnsArray()) {
>       colNames.put(fromCol.getName(), fromCol);
>     }
> 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
> {color:red}
> int fromIndex = getFromSchema().getColumnsList().indexOf(fromCol);
> {color}
> These performance problems are critical because getMatchingData is repeatedly calling
for each record.



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