Solr4.7 Cache Technology

Disk IO is often a prominent bottleneck in computer system response speed, search engine query is very ordinary, reduce the search process of disk IO to enhance the search response speed is undoubtedly a great help, in SOLR, provide a self-contained cache mechanism. We just need to add a few configuration items to the Solrconfig.xml.

Let's take a look at SOLR's 3 caches.

Filter cache: This is the result of the cache filter (that is, query parameter FQ) and the basic enumeration type.

Document cache: This is the thing that is used to cache Lucene documents, which is the one that stores the field.

Query Result cache: This is a glance that caches the results of queries.

First, cache configuration

SOLR's cache configuration is in the query configuration section of the Solrconfig.xml file, which is between the <query> and </query> tags. SOLR implements 2 kinds of caching mechanisms, namely LRUCache, Fastlrucache;

LRUCache: Thread-safe linkedhashmap implementation.

Fastlrucache: Based on CONCURRENTHASHMAP implementation.

A single-threaded case Fastlrucache has a faster get operation and slower puts operations, so the query hit rate using it will be higher than LRUCache 75%, although the gap may be greater in multi-threaded situations.

Parameter description:

Class: Specifies which caching mechanism to use with SOLR.

Size: The amount of cache space that is allowed to allocate the number of entities (entity).

InitialSize: Allocates cache space for the initial number of entities (entity).

Autowarmcount: The number of entities that are automatically preloaded in.

1. Filter Cache

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1. <Filtercache
2. class="SOLR. Fastlrucache "
3. size="
4. initialsize="
5. autowarmcount="/> "

2, Documentcache

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1. <Queryresultcache
2. class="SOLR. Fastlrucache "
3. size="
4. initialsize="
5. autowarmcount="/> "

3. QueryResult Cache

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1. <Documentcache
2. class="SOLR. Fastlrucache "
3. size="11000"
4. initialsize="11000" />

4. Query Result window value setting

The query Result window value is used with query result cache. What is the concept of this value is that I set the Query Results window value of 50, I query 20 to 30 of the data, the first query SOLR will be removed from the index library 0 to 49 of the data, I will not have to page the index library to query, directly from the cache to take it, Greatly improves the query response speed.

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1. <queryresultwindowsize>50</queryresultwindowsize>

Second, complete configuration

2. <!--cache configuration--
4. <query>
6. <!--filter cache-->
8. <filtercache
10. class="SOLR. Fastlrucache "
12. size="
14. initialsize="
16. autowarmcount="/> "
20. <!--query results cache-->
22. <queryresultcache
24. class="SOLR. Fastlrucache "
26. size="
28. initialsize="
30. autowarmcount="/> "
34. <!--document Cache-->
36. <documentcache
38. class="SOLR. Fastlrucache "
40. size="11000"
42. initialsize="11000" />
46. <queryresultwindowsize>200</queryresultwindowsize>
48. </Query>
    

Solr4.7 Cache Technology