github.com/weaviate/weaviate@v1.24.6/adapters/repos/db/lsmkv/memtable_size_advisor.go (about)

     1  //                           _       _
     2  // __      _____  __ ___   ___  __ _| |_ ___
     3  // \ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \
     4  //  \ V  V /  __/ (_| |\ V /| | (_| | ||  __/
     5  //   \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___|
     6  //
     7  //  Copyright © 2016 - 2024 Weaviate B.V. All rights reserved.
     8  //
     9  //  CONTACT: hello@weaviate.io
    10  //
    11  
    12  package lsmkv
    13  
    14  import "time"
    15  
    16  // if not enough config is provided we can fall back to this reasonable default
    17  // value
    18  const reasonableMemtableDefault = 10 * 1024 * 1024
    19  
    20  type memtableSizeAdvisorCfg struct {
    21  	initial     int
    22  	stepSize    int
    23  	maxSize     int
    24  	minDuration time.Duration
    25  	maxDuration time.Duration
    26  }
    27  
    28  type memtableSizeAdvisor struct {
    29  	cfg    memtableSizeAdvisorCfg
    30  	active bool
    31  }
    32  
    33  func newMemtableSizeAdvisor(cfg memtableSizeAdvisorCfg) *memtableSizeAdvisor {
    34  	a := &memtableSizeAdvisor{
    35  		cfg: cfg,
    36  	}
    37  
    38  	// only activate if initial size, step size, max size, and max duration are
    39  	// given
    40  	if a.cfg.maxSize > 0 && a.cfg.initial > 0 && a.cfg.stepSize > 0 && a.cfg.maxDuration > 0 {
    41  		a.active = true
    42  	}
    43  
    44  	return a
    45  }
    46  
    47  func (m memtableSizeAdvisor) Initial() int {
    48  	if m.active {
    49  		return m.cfg.initial
    50  	} else {
    51  		return reasonableMemtableDefault
    52  	}
    53  }
    54  
    55  func (m memtableSizeAdvisor) NextTarget(previousTarget int,
    56  	timeSinceFlush time.Duration,
    57  ) (int, bool) {
    58  	if !m.active {
    59  		return reasonableMemtableDefault, false
    60  	}
    61  
    62  	if timeSinceFlush < m.cfg.minDuration {
    63  		next := min(previousTarget+m.cfg.stepSize, m.cfg.maxSize)
    64  		return next, next != previousTarget
    65  	}
    66  	if timeSinceFlush > m.cfg.maxDuration {
    67  		next := max(previousTarget-m.cfg.stepSize, m.cfg.initial)
    68  		return next, next != previousTarget
    69  	}
    70  	return previousTarget, false
    71  }
    72  
    73  func min(a, b int) int {
    74  	if a <= b {
    75  		return a
    76  	}
    77  
    78  	return b
    79  }
    80  
    81  func max(a, b int) int {
    82  	if a >= b {
    83  		return a
    84  	}
    85  
    86  	return b
    87  }