druid/indexing-hadoop
Gian Merlino 1c7a03a47b
Lower default maxRowsInMemory for realtime ingestion. (#13939)
* Lower default maxRowsInMemory for realtime ingestion.

The thinking here is that for best ingestion throughput, we want
intermediate persists to be as big as possible without using up all
available memory. So, we rely mainly on maxBytesInMemory. The default
maxRowsInMemory (1 million) is really just a safety: in case we have
a large number of very small rows, we don't want to get overwhelmed
by per-row overheads.

However, maximum ingestion throughput isn't necessarily the primary
goal for realtime ingestion. Query performance is also important. And
because query performance is not as good on the in-memory dataset, it's
helpful to keep it from growing too large. 150k seems like a reasonable
balance here. It means that for a typical 5 million row segment, we
won't trigger more than 33 persists due to this limit, which is a
reasonable number of persists.

* Update tests.

* Update server/src/main/java/org/apache/druid/segment/indexing/RealtimeTuningConfig.java

Co-authored-by: Kashif Faraz <kashif.faraz@gmail.com>

* Fix test.

* Fix link.

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Co-authored-by: Kashif Faraz <kashif.faraz@gmail.com>
2023-03-21 10:36:36 -07:00
..
src Lower default maxRowsInMemory for realtime ingestion. (#13939) 2023-03-21 10:36:36 -07:00
pom.xml merge druid-core, extendedset, and druid-hll into druid-processing to simplify everything (#13698) 2023-02-17 14:27:41 -08:00