-
Notifications
You must be signed in to change notification settings - Fork 2.3k
/
NonUniqueIndexSampler.java
106 lines (88 loc) · 2.86 KB
/
NonUniqueIndexSampler.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel.impl.api.index.sampling;
import org.neo4j.helpers.collection.MultiSet;
import org.neo4j.storageengine.api.schema.IndexSample;
public class NonUniqueIndexSampler
{
private static final int INITIAL_SIZE = 1 << 16;
private final int bufferSizeLimit;
private final MultiSet<String> values;
private int sampledSteps = 0;
// kept as longs to side step overflow issues
private long accumulatedUniqueValues = 0;
private long accumulatedSampledSize = 0;
private long bufferSize = 0;
public NonUniqueIndexSampler( int bufferSizeLimit )
{
this.bufferSizeLimit = bufferSizeLimit;
this.values = new MultiSet<>( INITIAL_SIZE );
}
public void include( String value )
{
include( value, 1 );
}
public void include( String value, long increment )
{
assert increment > 0;
if ( bufferSize >= bufferSizeLimit )
{
nextStep();
}
if ( values.increment( value, increment ) == increment )
{
bufferSize += value.length();
}
}
public void exclude( String value )
{
exclude( value, 1 );
}
public void exclude( String value, long decrement )
{
assert decrement > 0;
if ( values.increment( value, -decrement ) == 0 )
{
bufferSize -= value.length();
}
}
public IndexSample result()
{
return result( -1 );
}
public IndexSample result( int numDocs )
{
if ( !values.isEmpty() )
{
nextStep();
}
long uniqueValues = sampledSteps != 0 ? accumulatedUniqueValues / sampledSteps : 0;
long sampledSize = sampledSteps != 0 ? accumulatedSampledSize / sampledSteps : 0;
return new IndexSample( numDocs < 0 ? accumulatedSampledSize : numDocs, uniqueValues, sampledSize );
}
private void nextStep()
{
accumulatedUniqueValues += values.uniqueSize();
accumulatedSampledSize += values.size();
bufferSize = 0;
sampledSteps++;
values.clear();
}
}