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Posted to mapreduce-issues@hadoop.apache.org by "Tomoya Tainaka (JIRA)" <ji...@apache.org> on 2011/04/26 04:07:03 UTC
[jira] [Updated] (MAPREDUCE-2453) DBinputFormat throws OutOfMemory
exceptions when importing large tables from PostgreSQL.
[ https://issues.apache.org/jira/browse/MAPREDUCE-2453?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tomoya Tainaka updated MAPREDUCE-2453:
--------------------------------------
Attachment: MAPREDUCE-2453-4.patch
MAPREDUCE-2453-3.patch
MAPREDUCE-2453-2.patch
MAPREDUCE-2453-1.patch
> DBinputFormat throws OutOfMemory exceptions when importing large tables from PostgreSQL.
> ----------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-2453
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2453
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Affects Versions: 0.21.0
> Reporter: Tomoya Tainaka
> Priority: Minor
> Attachments: MAPREDUCE-2453-1.patch, MAPREDUCE-2453-2.patch, MAPREDUCE-2453-3.patch, MAPREDUCE-2453-4.patch
>
>
> DBinputFormat throws OutOfMemory exceptions and Java heap space errors when importing large tables from PostgreSQL. This is because loading the whole resultset into memory at the same time. As a consequence, the Java heap space is exhausted.
> Also, this problem happens with DataDrivenDBInputFormat.
> I suggest utilizing "Fetch Size" parameter of JDBC within DBInputFormat.
> I made patches as follows:
> ・modifying org.apache.hadoop.mapreduce.lib.db.DBInputFormat.
> ・creating org.apache.hadoop.mapreduce.PostgreSQLDBRecordReader.java.
> ・adding JDBC options of fetch size, which are setFetchSize() and setAutoCommit().
> I also modified DataDrivenDBinputFormat in the same way as DBInputFormat.
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