...
Auto compaction ensures that appended import jobs always store data efficiently even if they run very frequently. Example: If an import job is run every hour, this generates 24 files every day. If you run it even more often there are more files of smaller size. This process could lead to a high fragmentation of your data into a lot of small files and Hadoop is less efficient when processing these. Auto compaction compacts those files automatically on a daily or monthly basis depending on the configured schedule of an import job. This process ensures the best system performance regardless of the import job update interval. Click Pause to stop auto compaction. To restart it, click Resume.
...