Improving the Lifecycle Query Engine performance by compacting indexed data

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Each time you index the data from your lifecycle management applications, the amount of space required to store that data increases. Over time, as the index files get larger and the amount of available hard disk space decreases, you might experience server performance issues. You can take steps to prevent this situation by monitoring the hard disk usage and, when required, compacting the indexed data.

Because disk space is not reclaimed when you delete data from the index, you should consider running a compaction any time you delete or reindex the data.

If you deployed Lifecycle Query Engine (LQE) across several nodes, you can select specific nodes for data compaction.

When you start to compact indexed data, the indexing service is turned off. You can, however, run queries while the data is being compacted. When the compacting process ends, the older index is replaced with the new compacted index.

During compaction, the indexed data is exported to N-Quads format, which is a line-based, plain text format for encoding an resource description framework (RDF) data set. For more information about the N-Quads format, see RDF N-Quads on the W3C website.

You can modify the compaction heap size that can help curtail these JVM heap space issues. Compactions are run as separate JRE processes (from LQE) and require their own Java™ heap size to be set. To change the Java heap size in the LQE application, go to Administration > Advanced Properties > Show Internal > Edit . In the Compaction section, change the Maximum Heap (MB) size from 4096 to 8192 MB. Save your changes and retry the compaction.

Before you begin

Ensure that the disk space is at least two times the current size of the indexes under <JTSInstallDir>\server\conf\lqe.

Procedure

  1. On the LQE administration page, under Configuration, click Compaction.
  2. On the Compaction page, click Compact Now.
    Screen capture of the Compaction page. The Compact Now dialog box is open and the node is selected.
  3. Select the node that you want to compact, and click Compact Now.

What to do next

A compaction task is enabled to run weekly. You can modify the schedule, or configure the task to run on specific nodes. Click the Edit Schedule link, select the node, the time, and the days of the week. Select Yes to enable the schedule, then save your configuration.
Screen capture of the Compaction scheduling page.