Stefan Egli created OAK-3976:
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Summary: journal should support large(r) entries
Key: OAK-3976
URL: https://issues.apache.org/jira/browse/OAK-3976
Project: Jackrabbit Oak
Issue Type: Improvement
Components: documentmk
Affects Versions: 1.3.14
Reporter: Stefan Egli
Fix For: 1.6
Journal entries are created in the background write. Normally this happens
every second. If for some reason there is a large delay between two background
writes, the number of journal entries can also accumulate. Which can result in
(arbitrary) large single journal entries (ie with large {{_c}} property).
This can cause multiple problems down the road:
* journal gc at this point loads 450 entries - and if some are large this can
result in a very large memory consumption during gc (which can cause severe
stability problems for the VM, if not OOM etc). This should be fixed with
OAK-3001 (where we only get the id, thus do not care how big {{_c}} is)
* before OAK-3001 is done (which is currently scheduled after 1.4) what we can
do is reduce the delete batch size (OAK-3975)
* background reads however also read the journal entries and even if
OAK-3001/OAK-3975 are implemented the background read can still cause large
memory consumption. So we need to improve this one way or another.
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