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Maksim Zhuravkov updated IGNITE-23335: -------------------------------------- Summary: Sql. Do not store aggregation state in Accumulators (was: Sql. Do not store aggregation state in Accumulator) > Sql. Do not store aggregation state in Accumulators > --------------------------------------------------- > > Key: IGNITE-23335 > URL: https://issues.apache.org/jira/browse/IGNITE-23335 > Project: Ignite > Issue Type: Improvement > Components: sql > Reporter: Maksim Zhuravkov > Priority: Major > Labels: ignite-3 > > `Accumulator` stores aggregation state, we should extract this state making > `Accumulator` pure functions. > Current accumulator (except methods that return result types). > {code:java} > public interface Accumulator { > void add(Object... args); > Object end(); > {code} > DoubleAvg example: > {code:java} > public static class DoubleAvg implements Accumulator { > public static final Supplier<Accumulator> FACTORY = DoubleAvg::new; > private double sum; > private long cnt; > /** {@inheritDoc} */ > @Override > public void add(Object... args) { > Double in = (Double) args[0]; > if (in == null) { > return; > } > sum += in; > cnt++; > } > /** {@inheritDoc} */ > @Override > public Object end() { > return cnt > 0 ? sum / cnt : null; > } > {code} > New accumulator interface: > {code:java} > public interface Accumulator { > void init(AggregateState state); > void update(AggregateState state, arguments); > void end(AggregateState state); > {code} > Aggregate should be stored in aggregate operators (HashAggregateNode, ). We > should also move DistinctAccumulator (AVG(DISTINCT x) to HashAggregateNode -- This message was sent by Atlassian Jira (v8.20.10#820010)