github.com/m3db/m3@v1.5.1-0.20231129193456-75a402aa583b/src/dbnode/storage/index/results_utilization_stats.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    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  }