Linq内存不足异常

Question

当我执行此代码时

Dim lstOrders = (From oRR In dbO.orders
                 Where oRR.datum = werkdatum And oRR.status >= 40).ToList

Dim lstOrderRegels = (From ord In lstOrders
                     Join ordreg In dbO.orderregels On ord.ID Equals ordreg.ordernummer
                     Group Join a In dbO.artikelen On ordreg.artikelID Equals a.ID Into resultArt = Group
                     From art In resultArt.DefaultIfEmpty(New artikelen With {.ID = 0, .subgroep = 0})
                     Group Join subgr In dbO.productsubgroep On art.subgroep Equals subgr.ID Into result = Group
                     From sgr In result.DefaultIfEmpty(New productsubgroep With {.ID = 0, .productgroep_ID = 0})
                     Group Join hgr In dbO.productgroep On sgr.productgroep_ID Equals hgr.ID Into result2 = Group
                     From hg In result2.DefaultIfEmpty(New productgroep With {.ID = 0})
                     Join ses In dbO.sessie On ord.sessieID Equals ses.ID
                     Order By hg.code, sgr.code).ToList

我得到一个系统内存不足的问题。首先，虽然它可能是其中一列中的空值，但即使将其更改为0也没有帮助。第二个查询应返回大约4k的结果。