Question

我收到以下NHibernate超时异常：

could not execute query

内部异常消息为：

Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

这是失败的NHibernate代码：

shareClassReturns = _session.CreateCriteria<ShareClassTrailingReturn>()
        .Add(LambdaSubquery.Property<ShareClassTrailingReturn>(x => x.ShareClass.Id).In(GetAvailableShareClassIds()))
        .Add(LambdaSubquery.Property<ShareClassTrailingReturn>(x => x.ShareClass.Id).In(GetShareclassIdsInCalculationGroup(peerGroups, classificationTypes)))
        .Add<ShareClassTrailingReturn>(c => c.CurrencyId == "GBP")
        .AddShareClassReturnOrder(order)
        .CreateCriteria<ShareClassTrailingReturn>(scr => scr.ShareClass, JoinType.InnerJoin)
        .Add(ApplicableIdentifiers(searchExpression))
        .AddShareClassOrder(order)
        .SetMaxResults(pageSize)
        .List<ShareClassTrailingReturn>();

这是我通过NHibernate Profiler看到的SQL（虽然我已经整理了一下，并用select top 25 *替换了我选择的所有项目以使其更具可读性：

SELECT   top 25 *
FROM     offline.ShareClassTrailingReturn this_
         inner join ShareManager.ShareClass shareclass1_
           on this_.SCTR_ShareClassId = shareclass1_.ShareClass_Id
         left outer join DCS.ShareClassInfo shareclass1_1_
           on shareclass1_.ShareClass_Id = shareclass1_1_.[ShareClassInfo_MSShareClassId]
WHERE    
    this_.SCTR_ShareClassId in 
    (
        SELECT this_0_.[Fund_ID] as y0_
        FROM   dbo.Fund this_0_
            inner join CAP.DataUniverse datauniver1_
              on this_0_.[Fund_TypeID] = datauniver1_.[DataUniverse_TypeId]
                 and this_0_.[Fund_CountryID] = datauniver1_.[DataUniverse_CountryID]
        WHERE  datauniver1_.[DataUniverse_SiteId] = 100 /* @p0 */
    )
    and this_.SCTR_ShareClassId in 
    (
        SELECT this_0_.ShareClass_Id as y0_
        FROM   dbo.vCalculationGroup this_0_
        WHERE  
            this_0_.PeerGroupId in (1,8)
            and this_0_.ClassificationId in (7,1)
    )
    and this_.SCTR_CurrencyId = 'GBP'
    and 
    (
        shareclass1_.ShareClass_MEX like '%axa%' 
        or shareclass1_.ShareClass_SEDOL like '%axa%'
        or shareclass1_1_.ShareClassInfo_RIC like '%axa%'
        or shareclass1_.ShareClass_ISIN like '%axa%'
        or shareclass1_.ShareClass_CUSIP like '%axa%'
    )
ORDER BY shareclass1_.ShareClass_Name asc

如果我更改NHibernate标准，以便它不对vCalculationGroup执行选择，即如果我删除此行：

.Add(LambdaSubquery.Property<ShareClassTrailingReturn>(x => x.ShareClass.Id).In(GetShareclassIdsInCalculationGroup(peerGroups, classificationTypes)))

或来自SQL

    and this_.SCTR_ShareClassId in 
    (
        SELECT this_0_.ShareClass_Id as y0_
        FROM   dbo.vCalculationGroup this_0_
        WHERE  
            this_0_.PeerGroupId in (1,8)
            and this_0_.ClassificationId in (7,1)
    )

查询不再超时。这是否意味着我需要对该视图执行某些操作？像索引还是什么？

有人可以建议我如何解决这个问题吗？

编辑：我应该补充说，查询在SQL Server Management Studio中运行良好，并在大约6秒后返回。虽然如此，当我查看执行计划时，它会报告在offline.ShareClassTrailingReturn上缺少索引。这可能是问题吗？

Answer 1

如果删除该部分使其更好地工作，我肯定会看一下视图的索引。在您的应用程序中检查连接超时也是值得的。如果你说它在6秒内在Management Studio中工作正常，则可能是你的应用程序连接超时少于6秒（或默认值较小）。那些将是很好的起点。

值得尝试一般避免大量嵌套子查询。您在生成的SQL中有很多。有时，自己编写SQL或HQL更有效，而不是在Criteria或Linq NHibernate API中使用大量复杂的连接。你更有可能为这份工作生成高效的SQL！

NHibernate查询超时

1 个答案: