performance.pot

hibernate-distribution-3.3.1.GA-dist.zip源码

#, no-c-format
msgid "SwarmCache"
msgstr ""

#. Tag: literal
#: performance.xml:656
#, no-c-format
msgid "org.hibernate.cache.SwarmCacheProvider"
msgstr ""

#. Tag: entry
#: performance.xml:657
#, no-c-format
msgid "clustered (ip multicast)"
msgstr ""

#. Tag: entry
#: performance.xml:658
#, no-c-format
msgid "yes (clustered invalidation)"
msgstr ""

#. Tag: entry
#: performance.xml:662 performance.xml:850
#, no-c-format
msgid "JBoss Cache 1.x"
msgstr ""

#. Tag: literal
#: performance.xml:663
#, no-c-format
msgid "org.hibernate.cache.TreeCacheProvider"
msgstr ""

#. Tag: entry
#: performance.xml:664 performance.xml:671
#, no-c-format
msgid "clustered (ip multicast), transactional"
msgstr ""

#. Tag: entry
#: performance.xml:665
#, no-c-format
msgid "yes (replication)"
msgstr ""

#. Tag: entry
#: performance.xml:666 performance.xml:673
#, no-c-format
msgid "yes (clock sync req.)"
msgstr ""

#. Tag: entry
#: performance.xml:669 performance.xml:857
#, no-c-format
msgid "JBoss Cache 2"
msgstr ""

#. Tag: literal
#: performance.xml:670
#, no-c-format
msgid "org.hibernate.cache.jbc2.JBossCacheRegionFactory"
msgstr ""

#. Tag: entry
#: performance.xml:672
#, no-c-format
msgid "yes (replication or invalidation)"
msgstr ""

#. Tag: title
#: performance.xml:680
#, no-c-format
msgid "Cache mappings"
msgstr ""

#. Tag: para
#: performance.xml:682
#, no-c-format
msgid "The <literal>&lt;cache&gt;</literal> element of a class or collection mapping has the following form:"
msgstr ""

#. Tag: programlisting
#: performance.xml:693
#, no-c-format
msgid ""
      "<![CDATA[<cache \n"
      "    usage=\"transactional|read-write|nonstrict-read-write|read-only\"\n"
      "    region=\"RegionName\"\n"
      "    include=\"all|non-lazy\"\n"
      "/>]]>"
msgstr ""

#. Tag: para
#: performance.xml:696
#, no-c-format
msgid "<literal>usage</literal> (required) specifies the caching strategy: <literal>transactional</literal>, <literal>read-write</literal>, <literal>nonstrict-read-write</literal> or <literal>read-only</literal>"
msgstr ""

#. Tag: para
#: performance.xml:705
#, no-c-format
msgid "<literal>region</literal> (optional, defaults to the class or collection role name) specifies the name of the second level cache region"
msgstr ""

#. Tag: para
#: performance.xml:712
#, no-c-format
msgid "<literal>include</literal> (optional, defaults to <literal>all</literal>) <literal>non-lazy</literal> specifies that properties of the entity mapped with <literal>lazy=\"true\"</literal> may not be cached when attribute-level lazy fetching is enabled"
msgstr ""

#. Tag: para
#: performance.xml:722
#, no-c-format
msgid "Alternatively (preferably?), you may specify <literal>&lt;class-cache&gt;</literal> and <literal>&lt;collection-cache&gt;</literal> elements in <literal>hibernate.cfg.xml</literal>."
msgstr ""

#. Tag: para
#: performance.xml:727
#, no-c-format
msgid "The <literal>usage</literal> attribute specifies a <emphasis>cache concurrency strategy</emphasis>."
msgstr ""

#. Tag: title
#: performance.xml:734
#, no-c-format
msgid "Strategy: read only"
msgstr ""

#. Tag: para
#: performance.xml:736
#, no-c-format
msgid "If your application needs to read but never modify instances of a persistent class, a <literal>read-only</literal> cache may be used. This is the simplest and best performing strategy. It's even perfectly safe for use in a cluster."
msgstr ""

#. Tag: programlisting
#: performance.xml:742
#, no-c-format
msgid ""
      "<![CDATA[<class name=\"eg.Immutable\" mutable=\"false\">\n"
      "    <cache usage=\"read-only\"/>\n"
      "    ....\n"
      "</class>]]>"
msgstr ""

#. Tag: title
#: performance.xml:748
#, no-c-format
msgid "Strategy: read/write"
msgstr ""

#. Tag: para
#: performance.xml:750
#, no-c-format
msgid "If the application needs to update data, a <literal>read-write</literal> cache might be appropriate. This cache strategy should never be used if serializable transaction isolation level is required. If the cache is used in a JTA environment, you must specify the property <literal>hibernate.transaction.manager_lookup_class</literal>, naming a strategy for obtaining the JTA <literal>TransactionManager</literal>. In other environments, you should ensure that the transaction is completed when <literal>Session.close()</literal> or <literal>Session.disconnect()</literal> is called. If you wish to use this strategy in a cluster, you should ensure that the underlying cache implementation supports locking. The built-in cache providers do <emphasis>not</emphasis>."
msgstr ""

#. Tag: programlisting
#: performance.xml:761
#, no-c-format
msgid ""
      "<![CDATA[<class name=\"eg.Cat\" .... >\n"
      "    <cache usage=\"read-write\"/>\n"
      "    ....\n"
      "    <set name=\"kittens\" ... >\n"
      "        <cache usage=\"read-write\"/>\n"
      "        ....\n"
      "    </set>\n"
      "</class>]]>"
msgstr ""

#. Tag: title
#: performance.xml:766
#, no-c-format
msgid "Strategy: nonstrict read/write"
msgstr ""

#. Tag: para
#: performance.xml:768
#, no-c-format
msgid "If the application only occasionally needs to update data (ie. if it is extremely unlikely that two transactions would try to update the same item simultaneously) and strict transaction isolation is not required, a <literal>nonstrict-read-write</literal> cache might be appropriate. If the cache is used in a JTA environment, you must specify <literal>hibernate.transaction.manager_lookup_class</literal>. In other environments, you should ensure that the transaction is completed when <literal>Session.close()</literal> or <literal>Session.disconnect()</literal> is called."
msgstr ""

#. Tag: title
#: performance.xml:780
#, no-c-format
msgid "Strategy: transactional"
msgstr ""

#. Tag: para
#: performance.xml:782
#, no-c-format
msgid "The <literal>transactional</literal> cache strategy provides support for fully transactional cache providers such as JBoss TreeCache. Such a cache may only be used in a JTA environment and you must specify <literal>hibernate.transaction.manager_lookup_class</literal>."
msgstr ""

#. Tag: title
#: performance.xml:791
#, no-c-format
msgid "Cache-provider/concurrency-strategy compatibility"
msgstr ""

#. Tag: para
#: performance.xml:794
#, no-c-format
msgid "None of the cache providers support all of the cache concurrency strategies."
msgstr ""

#. Tag: para
#: performance.xml:799
#, no-c-format
msgid "The following table shows which providers are compatible with which concurrency strategies."
msgstr ""

#. Tag: title
#: performance.xml:804
#, no-c-format
msgid "Cache Concurrency Strategy Support"
msgstr ""

#. Tag: entry
#: performance.xml:814
#, no-c-format
msgid "read-only"
msgstr ""

#. Tag: entry
#: performance.xml:815
#, no-c-format
msgid "nonstrict-read-write"
msgstr ""

#. Tag: entry
#: performance.xml:816
#, no-c-format
msgid "read-write"
msgstr ""

#. Tag: entry
#: performance.xml:817
#, no-c-format
msgid "transactional"
msgstr ""

#. Tag: title
#: performance.xml:872
#, no-c-format
msgid "Managing the caches"
msgstr ""

#. Tag: para
#: performance.xml:874
#, no-c-format
msgid "Whenever you pass an object to <literal>save()</literal>, <literal>update()</literal> or <literal>saveOrUpdate()</literal> and whenever you retrieve an object using <literal>load()</literal>, <literal>get()</literal>, <literal>list()</literal>, <literal>iterate()</literal> or <literal>scroll()</literal>, that object is added to the internal cache of the <literal>Session</literal>."
msgstr ""

#. Tag: para
#: performance.xml:881
#, no-c-format
msgid "When <literal>flush()</literal> is subsequently called, the state of that object will be synchronized with the database. If you do not want this synchronization to occur or if you are processing a huge number of objects and need to manage memory efficiently, the <literal>evict()</literal> method may be used to remove the object and its collections from the first-level cache."
msgstr ""

#. Tag: programlisting
#: performance.xml:889
#, no-c-format
msgid ""
      "<![CDATA[ScrollableResult cats = sess.createQuery(\"from Cat as cat\").scroll(); //a huge result set\n"
      "while ( cats.next() ) {\n"
      "    Cat cat = (Cat) cats.get(0);\n"
      "    doSomethingWithACat(cat);\n"
      "    sess.evict(cat);\n"
      "}]]>"
msgstr ""

#. Tag: para
#: performance.xml:891
#, no-c-format
msgid "The <literal>Session</literal> also provides a <literal>contains()</literal> method to determine if an instance belongs to the session cache."
msgstr ""

#. Tag: para
#: performance.xml:896
#, no-c-format
msgid "To completely evict all objects from the session cache, call <literal>Session.clear()</literal>"
msgstr ""

#. Tag: para
#: performance.xml:900
#, no-c-format
msgid "For the second-level cache, there are methods defined on <literal>SessionFactory</literal> for evicting the cached state of an instance, entire class, collection instance or entire collection role."
msgstr ""

#. Tag: programlisting
#: performance.xml:906
#, no-c-format
msgid ""
      "<![CDATA[sessionFactory.evict(Cat.class, catId); //evict a particular Cat\n"
      "sessionFactory.evict(Cat.class);  //evict all Cats\n"
      "sessionFactory.evictCollection(\"Cat.kittens\", catId); //evict a particular collection of kittens\n"
      "sessionFactory.evictCollection(\"Cat.kittens\"); //evict all kitten collections]]>"
msgstr ""

#. Tag: para
#: performance.xml:908
#, no-c-format
msgid "The <literal>CacheMode</literal> controls how a particular session interacts with the second-level cache."
msgstr ""

#. Tag: para
#: performance.xml:915
#, no-c-format
msgid "<literal>CacheMode.NORMAL</literal> - read items from and write items to the second-level cache"
msgstr ""

#. Tag: para
#: performance.xml:920
#, no-c-format
msgid "<literal>CacheMode.GET</literal> - read items from the second-level cache, but don't write to the second-level cache except when updating data"
msgstr ""

#. Tag: para
#: performance.xml:926
#, no-c-format
msgid "<literal>CacheMode.PUT</literal> - write items to the second-level cache, but don't read from the second-level cache"
msgstr ""

#. Tag: para
#: performance.xml:932
#, no-c-format
msgid "<literal>CacheMode.REFRESH</literal> - write items to the second-level cache, but don't read from the second-level cache, bypass the effect of <literal>hibernate.cache.use_minimal_puts</literal>, forcing a refresh of the second-level cache for all items read from the database"
msgstr ""

#. Tag: para
#: performance.xml:940
#, no-c-format
msgid "To browse the contents of a second-level or query cache region, use the <literal>Statistics</literal> API:"
msgstr ""

#. Tag: programlisting
#: performance.xml:945
#, no-c-format
msgid ""
      "<![CDATA[Map cacheEntries = sessionFactory.getStatistics()\n"
      "        .getSecondLevelCacheStatistics(regionName)\n"
      "        .getEntries();]]>"
msgstr ""

#. Tag: para
#: performance.xml:947
#, no-c-format
msgid "You'll need to enable statistics, and, optionally, force Hibernate to keep the cache entries in a more human-understandable format:"
msgstr ""

#. Tag: programlisting
#: performance.xml:952
#, no-c-format
msgid ""
      "<![CDATA[hibernate.generate_statistics true\n"
      "hibernate.cache.use_structured_entries true]]>"
msgstr ""

#. Tag: title
#: performance.xml:957
#, no-c-format
msgid "The Query Cache"
msgstr ""

#. Tag: para
#: performance.xml:959
#, no-c-format
msgid "Query result sets may also be cached. This is only useful for queries that are run frequently with the same parameters. To use the query cache you must first enable it:"
msgstr ""

#. Tag: programlisting
#: performance.xml:964
#, no-c-format
msgid "<![CDATA[hibernate.cache.use_query_cache true]]>"
msgstr ""

#. Tag: para
#: performance.xml:966
#, no-c-format
msgid "This setting causes the creation of two new cache regions - one holding cached query result sets (<literal>org.hibernate.cache.StandardQueryCache</literal>), the other holding timestamps of the most recent updates to queryable tables (<literal>org.hibernate.cache.UpdateTimestampsCache</literal>). Note that the query cache does not cache the state of the actual entities in the result set; it caches only identifier values and results of value type. So the query cache should always be used in conjunction with the second-level cache."
msgstr ""

#. Tag: para
#: performance.xml:976
#, no-c-format
msgid "Most queries do not benefit from caching, so by default queries are not cached. To enable caching, call <literal>Query.setCacheable(true)</literal>. This call allows the query to look for existing cache results or add its results to the cache when it is executed."
msgstr ""