使用具有通用查询性能的 AsCacheQueryable 从 Ignite 获取数据

Question

我正在尝试在我的类 CacheHandler 中添加 Where 函数以从 Ignite 缓存中获取数据 我正在寻找使通用查询与 AsCacheQueryable 和 Where 子句一起使用以从 ignite 缓存返回数据的方法

//调用

var data = CacheHandler.Where2<LocalDb>(x => x.Value.localId== localId).FirstOrDefault();

//功能

    public ICache<string, T> GetCache<T>()
    {            
        var cacheName = CacheNames.GetCacheNameFromType<T>();
        
        if (cacheName == "")
        {
            throw new Exception("Invalid Cache name");
        }

        return _ignite.GetCache<string, T>(cacheName);
    }

    public List<T> Where2<T>(Func<ICacheEntry<string, T>, bool> query)
    {
        // 'System.Collections.Generic.List<Apache.Ignite.Core.Cache.ICacheEntry<string, T>>'
        var queryResult = GetCache<T>().AsCacheQueryable().Where(x => query(x));

        if (queryResult == null)
        {
            return new List<T>();
        }

        return queryResult.Select(x => x.Value).ToList();
    }

使用上述代码上下文忽略以下错误中的表名称。但是尝试获取数据时所有表的类似错误。 我在模型中的所有字段都有[QuerySqlField]

我收到以下错误：

    ""Hwb_Entity_Cache"".ENTITY AS _T0 WHERE _T0._KEY,[*] _T0._VAL "; SQL statement:
select _T0._VAL from "Hwb_Entity_Cache".ENTITY as _T0 where _T0._KEY, _T0._VAL [42000-197] (6e3f4055)
Apache.Ignite.Core.Common.IgniteException: Failed to parse query. Syntax error in SQL statement "SELECT _T0._VAL FROM ""Hwb_Entity_Cache"".ENTITY AS _T0 WHERE _T0._KEY,[*] _T0._VAL "; SQL statement:
select _T0._VAL from "Hwb_Entity_Cache".ENTITY as _T0 where _T0._KEY, _T0._VAL [42000-197]
 ---> Apache.Ignite.Core.Common.JavaException: class org.apache.ignite.IgniteCheckedException: Failed to parse query. Syntax error in SQL statement "SELECT _T0._VAL FROM ""Hwb_Entity_Cache"".ENTITY AS _T0 WHERE _T0._KEY,[*] _T0._VAL "; SQL statement:
select _T0._VAL from "Hwb_Entity_Cache".ENTITY as _T0 where _T0._KEY, _T0._VAL [42000-197]
    at org.apache.ignite.internal.processors.platform.utils.PlatformUtils.unwrapQueryException(PlatformUtils.java:520)
    at org.apache.ignite.internal.processors.platform.cache.PlatformCache.runFieldsQuery(PlatformCache.java:1321)
    at org.apache.ignite.internal.processors.platform.cache.PlatformCache.processInStreamOutObject(PlatformCache.java:940)
    at org.apache.ignite.internal.processors.platform.PlatformTargetProxyImpl.inStreamOutObject(PlatformTargetProxyImpl.java:79)
Caused by: javax.cache.CacheException: Failed to parse query. Syntax error in SQL statement "SELECT _T0._VAL FROM ""Hwb_Entity_Cache"".ENTITY AS _T0 WHERE _T0._KEY,[*] _T0._VAL "; SQL statement:
select _T0._VAL from "Hwb_Entity_Cache".ENTITY as _T0 where _T0._KEY, _T0._VAL [42000-197]
    at org.apache.ignite.internal.processors.cache.IgniteCacheProxyImpl.query(IgniteCacheProxyImpl.java:817)
    at org.apache.ignite.internal.processors.cache.GatewayProtectedCacheProxy.query(GatewayProtectedCacheProxy.java:412)
    at org.apache.ignite.internal.processors.platform.cache.PlatformCache.runFieldsQuery(PlatformCache.java:1315)
    ... 2 more
Caused by: class org.apache.ignite.internal.processors.query.IgniteSQLException: Failed to parse query. Syntax error in SQL statement "SELECT _T0._VAL FROM ""Hwb_Entity_Cache"".ENTITY AS _T0 WHERE _T0._KEY,[*] _T0._VAL "; SQL statement:
select _T0._VAL from "Hwb_Entity_Cache".ENTITY as _T0 where _T0._KEY, _T0._VAL [42000-197]
    at org.apache.ignite.internal.processors.query.h2.QueryParser.parseH2(QueryParser.java:584)
    at org.apache.ignite.internal.processors.query.h2.QueryParser.parse0(QueryParser.java:210)
    at org.apache.ignite.internal.processors.query.h2.QueryParser.parse(QueryParser.java:131)
    at org.apache.ignite.internal.processors.query.h2.IgniteH2Indexing.querySqlFields(IgniteH2Indexing.java:1103)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor$3.applyx(GridQueryProcessor.java:2406)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor$3.applyx(GridQueryProcessor.java:2402)
    at org.apache.ignite.internal.util.lang.IgniteOutClosureX.apply(IgniteOutClosureX.java:36)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor.executeQuery(GridQueryProcessor.java:2919)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor.lambda$querySqlFields$1(GridQueryProcessor.java:2422)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor.executeQuerySafe(GridQueryProcessor.java:2460)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor.querySqlFields(GridQueryProcessor.java:2396)
    at org.apache.ignite.internal.processors.query.GridQueryProcessor.querySqlFields(GridQueryProcessor.java:2323)
    at org.apache.ignite.internal.processors.cache.IgniteCacheProxyImpl.query(IgniteCacheProxyImpl.java:802)
    ... 4 more

有人可以建议在这里更正传递和阅读查询的方式吗？

Answer 1

AsCacheQueryable 是 Ignite.NET LINQ 提供程序的一部分 - 它将 LINQ 表达式树 转换为 Ignite SQL 方言。上面代码的问题是Func<ICacheEntry<string, T>, bool> query - 它应该是Expression<Func<ICacheEntry<string, T>, bool>> query。这对我有用：

public List<T> Where2<T>(Expression<Func<ICacheEntry<string, T>, bool>> query)
{
    var queryResult = GetCache<T>().AsCacheQueryable().Where(query);

    return queryResult.Select(x => x.Value).ToList();
}