eventsourcing/es4j

Problem: querying for aggregates is expensive

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#177 opened on Nov 6, 2016

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enhancementhelp wantedoptimization

Description

Querying for things like:

  • latest (as in, biggest TIMESTAMP) event for a certain scope (say, reference=R1)
  • sum/avg/max/min for a certain scope (say, reference=R1)

is quite expensive as it involved a lot of scanning (as can be seen in https://github.com/eventsourcing/es4j/blob/master/eventsourcing-queries/src/main/java/com/eventsourcing/queries/IsLatestEntity.java and https://github.com/eventsourcing/es4j/blob/master/eventsourcing-queries/src/main/java/com/eventsourcing/queries/LatestAssociatedEntryQuery.java)

Proposed solution: designate and formalize an aggregate indexing system.

Contributor guide

Tech stack
java
Domain
backenddatabaseperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Javaevent sourcingdatabase indexing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Explore the provided files IsLatestEntity.java and LatestAssociatedEntryQuery.java to understand current query implementation. Investigate indexing techniques like maintaining separate aggregate tables or using materialized views. Assess performance impact and design a formal aggregate indexing system that reduces full scan operations. Engage with maintainers for acceptance criteria.