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From "Nycholas de Oliveira e Oliveira (JIRA)" <j...@apache.org>
Subject [jira] [Created] (FLINK-7556) Fix fetch size configurable in JDBCInputFormat for MySQL Driver
Date Tue, 29 Aug 2017 16:57:00 GMT
Nycholas de Oliveira e Oliveira created FLINK-7556:
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             Summary: Fix fetch size configurable in JDBCInputFormat for MySQL Driver
                 Key: FLINK-7556
                 URL: https://issues.apache.org/jira/browse/FLINK-7556
             Project: Flink
          Issue Type: Bug
          Components: Batch Connectors and Input/Output Formats
    Affects Versions: 1.3.2
            Reporter: Nycholas de Oliveira e Oliveira
            Priority: Trivial


According to the MySQL documentation[1], it follows:

* ResultSet

??By default, ResultSets are completely retrieved and stored in memory. In most cases this
is the most efficient way to operate and, due to the design of the MySQL network protocol,
is easier to implement. If you are working with ResultSets that have a large number of rows
or large values and cannot allocate heap space in your JVM for the memory required, you can
tell the driver to stream the results back one row at a time.

To enable this functionality, create a Statement instance in the following manner:??

{code:java}
stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
              java.sql.ResultSet.CONCUR_READ_ONLY);
stmt.setFetchSize(Integer.MIN_VALUE);
{code}

??The combination of a forward-only, read-only result set, with a fetch size of Integer.MIN_VALUE
serves as a signal to the driver to stream result sets row-by-row. After this, any result
sets created with the statement will be retrieved row-by-row.
??

Allow the *Integer.MIN_VALUE* to be accepted as a parameter for _setFetchSize_.


[1] - https://dev.mysql.com/doc/connector-j/5.1/en/connector-j-reference-implementation-notes.html



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