Github user cestella commented on a diff in the pull request:
https://github.com/apache/metron/pull/990#discussion_r181853456
--- Diff: metron-platform/Performance-tuning-guide.md ---
@@ -43,6 +43,16 @@ parallelism will leave you with idle consumers since
Kafka limits the max number
important because Kafka has certain ordering guarantees for message
delivery per partition that would not be possible if more than
one consumer in a given consumer group were able to read from that
partition.
+## Parser Tuning Suggestions
+
+If you are using stellar field transformations in your parsers, by
default, stellar expressions
+are not cached. Turning on caching via setting the `cacheConfig`
[property](metron-parsers#parser_configuration)
+in your parser configuration can have performance impact if your stellar
expressions are
+complex (e.g. `ENRICHMENT_GET` calls or other high latency calls). The
tradeoff, though, is
+that non-deterministic stellar expressions will yield cached results which
may be wrong,
+for the period of time in which the data exists in the cache (the max time
in the cache is
+configurable).
+
--- End diff --
Thanks for the feedback. I've accepted your rewordings.
---
