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https://issues.apache.org/jira/browse/SQOOP-3022?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15553213#comment-15553213
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Ruslan Dautkhanov commented on SQOOP-3022:
------------------------------------------
I found this comment in source code
https://github.com/apache/sqoop/blob/7c1754270ff21f533088b946c873321f890da791/src/java/org/apache/sqoop/manager/oracle/OraOopOutputFormatInsert.java#L64
{quote}
// NB: "Direct inserts" cannot utilize APPEND_VALUES, otherwise Oracle
// will serialize
// the N mappers, causing a lot of lock contention.
{quote}
I don't think it's true if you don't have neither indexes nor FK constraints on
target table in Oracle.
See https://docs.oracle.com/cd/B19306_01/server.102/b14215/ldr_modes.htm :
{quote}
- Neither local or global indexes can be maintained by the load.
- Referential integrity and CHECK constraints must be disabled.
..
{quote}
If both of the above are satisfied, Oracle can do direct path insert from
multiple sessions (multiple sqoop export mappers' connections).
> sqoop export for Oracle generates tremendous amounts of redo logs
> -----------------------------------------------------------------
>
> Key: SQOOP-3022
> URL: https://issues.apache.org/jira/browse/SQOOP-3022
> Project: Sqoop
> Issue Type: Bug
> Components: codegen, connectors, connectors/oracle
> Affects Versions: 1.4.3, 1.4.4, 1.4.5, 1.4.6
> Reporter: Ruslan Dautkhanov
> Labels: export, oracle
>
> Sqoop export for Oracle generates tremendous amounts of redo logs (comparable
> to export size or more).
> We have put target tables in nologgin mode, but Oracle will still generate
> redo logs unless +APPEND Oracle insert hint is used.
> See https://oracle-base.com/articles/misc/append-hint for examples.
> Please add an option for sqoop to generate insert statements in Oracle with
> APPEND statement. Our databases are swamped with redo/archived logs whenever
> we sqoop data to them. This is easily avoidable. And from business
> prospective sqooping to staging tables in nologgin mode is totally fine.
> Thank you.
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