Raintung Li created SOLR-3684:
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Summary: Frequently full gc while do pressure index
Key: SOLR-3684
URL: https://issues.apache.org/jira/browse/SOLR-3684
Project: Solr
Issue Type: Improvement
Components: multicore
Affects Versions: 4.0-ALPHA
Environment: System: Linux
Java process: 4G memory
Jetty: 1000 threads
Index: 20 field
Core: 5
Reporter: Raintung Li
Priority: Critical
Recently we test the Solr index throughput and performance, configure the 20
fields do test, the field type is normal text_general, start 1000 threads for
Jetty, and define 5 cores.
After test continued for some time, the solr process throughput is down very
quickly. After check the root cause, find the java process always do the full
GC.
Check the heap dump, the main object is StandardTokenizer, it is be saved in
the CloseableThreadLocal by IndexSchema.SolrIndexAnalyzer.
In the Solr, will use the PerFieldReuseStrategy for the default reuse component
strategy, that means one field has one own StandardTokenizer if it use standard
analyzer, and standardtokenizer will occur 32KB memory because of zzBuffer
char array.
The worst case: Total memory = live threads*cores*fields*32KB
In the test case, the memory is 1000*5*20*32KB= 3.2G for StandardTokenizer, and
those object only thread die can be released.
Suggestion:
Every request only handles by one thread that means one document only analyses
by one thread. For one thread will parse the document’s field step by step, so
the same field type can use the same reused component. While thread switches
the same type’s field analyzes only reset the same component input stream, it
can save a lot of memory for same type’s field.
Total memory will be = live threads*cores*(different fields types)*32KB
The source code modifies that it is simple; I can provide the modification
patch for IndexSchema.java:
private class SolrIndexAnalyzer extends AnalyzerWrapper {
private class SolrFieldReuseStrategy extends ReuseStrategy {
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
public TokenStreamComponents getReusableComponents(String
fieldName) {
Map<Analyzer, TokenStreamComponents> componentsPerField =
(Map<Analyzer, TokenStreamComponents>) getStoredValue();
return componentsPerField != null ?
componentsPerField.get(analyzers.get(fieldName)) : null;
}
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
public void setReusableComponents(String fieldName,
TokenStreamComponents components) {
Map<Analyzer, TokenStreamComponents> componentsPerField =
(Map<Analyzer, TokenStreamComponents>) getStoredValue();
if (componentsPerField == null) {
componentsPerField = new HashMap<Analyzer,
TokenStreamComponents>();
setStoredValue(componentsPerField);
}
componentsPerField.put(analyzers.get(fieldName), components);
}
}
protected final static HashMap<String, Analyzer> analyzers;
/**
* Implementation of {@link ReuseStrategy} that reuses components per-field
by
* maintaining a Map of TokenStreamComponent per field name.
*/
SolrIndexAnalyzer() {
super(new solrFieldReuseStrategy());
analyzers = analyzerCache();
}
protected HashMap<String, Analyzer> analyzerCache() {
HashMap<String, Analyzer> cache = new HashMap<String, Analyzer>();
for (SchemaField f : getFields().values()) {
Analyzer analyzer = f.getType().getAnalyzer();
cache.put(f.getName(), analyzer);
}
return cache;
}
@Override
protected Analyzer getWrappedAnalyzer(String fieldName) {
Analyzer analyzer = analyzers.get(fieldName);
return analyzer != null ? analyzer :
getDynamicFieldType(fieldName).getAnalyzer();
}
@Override
protected TokenStreamComponents wrapComponents(String fieldName,
TokenStreamComponents components) {
return components;
}
}
private class SolrQueryAnalyzer extends SolrIndexAnalyzer {
@Override
protected HashMap<String, Analyzer> analyzerCache() {
HashMap<String, Analyzer> cache = new HashMap<String, Analyzer>();
for (SchemaField f : getFields().values()) {
Analyzer analyzer = f.getType().getQueryAnalyzer();
cache.put(f.getName(), analyzer);
}
return cache;
}
@Override
protected Analyzer getWrappedAnalyzer(String fieldName) {
Analyzer analyzer = analyzers.get(fieldName);
return analyzer != null ? analyzer :
getDynamicFieldType(fieldName).getQueryAnalyzer();
}
}
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