Question

有没有办法列出特定Cache中存在的所有表并列出Apache Ignite Server上的所有缓存？

----------------------------------修订------------ -------------- 嗨，我正在运行以下代码来了解缓存名称并列出缓存中存在的所有表。此程序列出服务器上存在的所有缓存名称。但是表格列表打印为空白集合。同时示例中的SQL查询工作正常。

public static void main(String[] args) throws Exception {
        System.out.println("Run Spring example!!");
        Ignition.setClientMode(true);
        IgniteConfiguration cfg = new IgniteConfiguration();
        cfg.setIncludeEventTypes( EVTS_CACHE);
        cfg.setPeerClassLoadingEnabled(true);
        TcpDiscoveryMulticastIpFinder discoveryMulticastIpFinder = new TcpDiscoveryMulticastIpFinder();
        Set<String> set = new HashSet<>();

        set.add("hostname:47500..47509");

        discoveryMulticastIpFinder.setAddresses(set);

        TcpDiscoverySpi discoverySpi = new TcpDiscoverySpi();
        discoverySpi.setIpFinder(discoveryMulticastIpFinder);

        cfg.setDiscoverySpi(discoverySpi);

        cfg.setPeerClassLoadingEnabled(true);
        cfg.setIncludeEventTypes(EVTS_CACHE);
        Ignite ignite = Ignition.start(cfg);

        System.out.println("All Available Cache on server : "+ignite.cacheNames());

        CacheConfiguration<String, BinaryObject> cacheConfiguration = new CacheConfiguration<>(CACHE_NAME);

        Collection<QueryEntity> entities = cacheConfiguration.getQueryEntities();
        System.out.println("All available tables in cache : "+entities);

        cacheConfiguration.setIndexedTypes(String.class, BinaryObject.class);
        //cacheConfiguration.setCacheMode(CacheMode.PARTITIONED);

        IgniteCache<String, BinaryObject> cache = ignite.getOrCreateCache(cacheConfiguration).withKeepBinary();

        System.out.println();





            QueryCursor<List<?>> query = cache.query(new SqlFieldsQuery("select Field1 from table1 where Field1='TEST'"));
            List<List<?>> all = query.getAll();
            for (List<?> l : all) {
                System.out.println(l);
            }

    }

Answer 1

获取所有缓存名称：Ignite.cacheNames()。然后使用Ignite.cache(String)获取缓存实例。

获取SQL表：

CacheConfiguration ccfg = cache.getConfiguration(CacheConfiguration.class);
Collection<QueryEntity> entities = ccfg.getQueryEntities();

每个查询实体代表一个表。

Answer 2

您可以使用h2查询阅读。从INFORMATION_SCHEMA.TABLES中选择TABLE_NAME，其中TABLE_SCHEMA是缓存名称

ClientConfiguration cfg = new ClientConfiguration().setAddresses(host+":"+port).
                        setUserName(username).setUserPassword(pwd); 
private static IgniteClient igniteClient = Ignition.startClient(cfg);
private static ClientCache<Integer, String>
 cache=igniteClient.getOrCreateCache(cacheName); 
QueryCursor<List<?>> cursor =cache.query(new SqlFieldsQuery("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES where TABLE_SCHEMA='"+cacheName+"'"));
                for (List<?> row : cursor) {
                    System.out.println(row.get(0));                           
                }

Answer 3

您可以使用Ignite.cacheNames()获取所有缓存名称。要获取所有表名，可以使用SHOW TABLES命令：

QueryCursor<List<?>> cursor = cache.query(new SqlFieldsQuery("SHOW TABLES FROM \""+CACHE_NAME+"\""));
for (List<?> row : cursor) {
    System.out.println(row.get(0));
}

有关SHOW命令的更多详细信息，请参见此处：http://www.h2database.com/html/grammar.html#show

Apache Ignite：如何列出所有表和所有缓存

3 个答案: