[9.0] New threadpool-based merge scheduler which is disk space aware#129134

Merged

albertzaharovits merged 14 commits intoelastic:9.0from

albertzaharovits:backport-90-disk-space-aware-threadpool-merge-scheduler

Jun 9, 2025

Commits on Jun 9, 2025

Threadpool merge scheduler (#120869)
albertzaharovits
committed
Start indexing throttling only after disk IO unthrottling does not keep up with the merge load (#125654)
albertzaharovits
committed
Slack merge throttling params for fewer merge tasks (#126016)
albertzaharovits
committed
Fix failure in ScalingThreadPoolTests after addition of merge scheduler (#125245)

mark-vieira
authored and
albertzaharovits
committed
Fix ThreadPoolMergeSchedulerStressTestIT testMergingFallsBehindAndThenCatchesUp (#125956)
albertzaharovits
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Fix testMergeSourceWithFollowUpMergesRunSequentially (#126050)
albertzaharovits
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Fix ThreadPoolMergeSchedulerTests testSchedulerCloseWaitsForRunningMerge (#126110)
albertzaharovits
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Fix IndexStatsIT (#126113)
albertzaharovits
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Threadpool merge executor is aware of available disk space (#127613)
albertzaharovits
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Expose merge events and their memory usage estimate (#126667)

pxsalehi
authored and
albertzaharovits
committed
Bring over merge scheduler features from stateless (#128155)

authored and
albertzaharovits
committed
Move MergeMemoryEstimator (#125686)

pxsalehi
authored and
albertzaharovits
committed
Remove unused project resolver reference
albertzaharovits
committed
Compilation fix
albertzaharovits
committed