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From "ilya.kasnacheev" <ilya.kasnach...@gmail.com>
Subject Re: Heap exhaustion when querying
Date Sat, 09 Jun 2018 14:37:41 GMT
Hello!

Sorry for the late reply! I think the good description of this flag is found
in JDBC driver's documentation.

https://apacheignite-sql.readme.io/docs/jdbc-driver#section-parameters

lazy

Lazy query execution.

By default, Ignite attempts to fetch the whole query result set to memory
and send it to the client. For small and medium result sets, this provides
optimal performance and minimize duration of internal database locks, thus
increasing concurrency.

However, if the result set is too big to fit in the available memory, then
it can lead to excessive GC pauses and even OutOfMemoryError. Use this flag
as a hint for Ignite to fetch the result set lazily, thus minimizing memory
consumption at the cost of moderate performance hit.

More on the concept of lazy evaluation:
https://en.wikipedia.org/wiki/Lazy_evaluation

Regards,



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