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Comment: Performance considerations

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Note
titleHighly Recommended to Update Database Sequences after a Large Restore

In some cases, when you restore a large amount of content to your DSpace, the internal database counts (called "sequences") may get out of sync with the Handles of the content you just restored. As a best practice, it is highly recommended to always re-run the "update-sequences.sql" script on your DSpace database after a larger scale restore. This database script should be run while DSpace is stopped (you may either stop Tomcat or just the DSpace webapps). PostgreSQL/Oracle must be running. The script can be found in the following locations for PostgreSQL and Oracle, respectively:
 [dspace]/etc/postgres/update-sequences.sql
 [dspace]/etc/oracle/update-sequences.sql

Performance considerations

When importing large structures like the whole site or a large collection/community, keep in mind that this can require a lot of memory, more than the default amount of heap allocated to the command-line launcher (256 Mb). This memory must be allocated in addition to the normal amount of memory allocated to Tomcat. For example, a site of 2500 fulltext items (2 Gb altogether) requires 5 Gb of maximum heap space and takes around 1 hour, including import and indexing.

You can raise the limit for a single run of the packager command by specifying memory options in the JAVA_OPTS environment variable, e.g.:

Code Block
JAVA_OPTS="-Xmx4096m -Dfile.encoding=UTF-8" /dspace/bin/dspace packager -u -r -a -f -t AIP -e dspace@example.com -i 123456789/0 sitewide-aip.zip

If the importer runs out of heap memory, it will crash either with "java.lang.OutOfMemoryError: GC overhead limit exceeded", which can be suppressed by adding "-XX:-UseGCOverheadLimit" to JAVA_OPTS, or with "java.lang.OutOfMemoryError: Java heap space". You can increase the allocated heap memory and try again, but keep in mind that although no changes were made in the database, the unsuccessfully imported files are still left in the assetstore (see DS-2227).

Additional Packager Options

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