github.com/m3db/m3@v1.5.0/src/dbnode/storage/index/results_utilization_stats.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
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     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
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    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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    19  // THE SOFTWARE.
    20  
    21  package index
    22  
    23  // resultsUtilizationStats tracks utilization of results object in order to detect and prevent
    24  // unbounded growth of reusable object which may otherwise stay in the object pool indefinitely.
    25  type resultsUtilizationStats struct {
    26  	resultsMapCapacity            int
    27  	consecutiveTimesUnderCapacity int
    28  }
    29  
    30  const (
    31  	consecutiveTimesUnderCapacityThreshold = 10
    32  )
    33  
    34  // updateAndCheck returns true iff the underlying object is supposed to be returned
    35  // to the appropriate object pool for reuse.
    36  func (r *resultsUtilizationStats) updateAndCheck(totalDocsCount int) bool {
    37  	if totalDocsCount < r.resultsMapCapacity {
    38  		r.consecutiveTimesUnderCapacity++
    39  	} else {
    40  		r.resultsMapCapacity = totalDocsCount
    41  		r.consecutiveTimesUnderCapacity = 0
    42  	}
    43  
    44  	// If the size of reusable result object is not fully utilized for a long enough time,
    45  	// we want to drop it from the pool and prevent holding on to excessive memory indefinitely.
    46  	return r.consecutiveTimesUnderCapacity < consecutiveTimesUnderCapacityThreshold
    47  }