EntityFramework dll

时间:2016-02-23 17:07:31

标签: c# entity-framework-6 predicatebuilder

当我尝试处理270k记录时,我收到此异常。它失败了12k。有人可以向我解释我错过了什么吗?

数据库是SQL,我使用的是EF 6.我使用谓词构建器来构建我的where子句。 这个想法是 select * from table where((a ='v1'和b ='v2')或(a ='v11'和b ='v21')或(a ='v12'和b ='v22')..) 我没有看到任何我仍然持有对我的代表EF类的对象的引用。我正在为我要发送回的视频创建一个POCO。 有什么想法吗?

另外我使用10000的CommandTimeout以及失败的点,当我在sql management studio中使用相同的参数运行查询时,它返回400行。

当我运行探查器时,我注意到在出现错误前几秒钟,内存使用率高达1GB +

由于

    public List<SearchResult> SearchDocuments(List<SearchCriteria> searchCriterias)
{
            List<SearchResult> results = new List<SearchResult>();
            var fieldSettings = GetData() ;// make a call to database to get this data
            using (var context = CreateContext())
            {
                var theQuery = PredicateBuilder.False<ViewInSqlDatabase>();
                int skipCount = 0;
                const int recordsToProcessInOneBatch = 100;
                while (searchCriterias.Skip(skipCount).Any())
                {
                    var searchCriteriasBatched = searchCriterias.Skip(skipCount).Take(recordsToProcessInOneBatch);
                    foreach (var searchCriteria in searchCriteriasBatched)
                    {
                        var queryBuilder = PredicateBuilder.True<ViewInSqlDatabase>();
                        // theQuery
                        if (searchCriteria.State.HasValue)
                            queryBuilder = queryBuilder.And(a => a.State == searchCriteria.State.Value);
                        if (!string.IsNullOrWhiteSpace(searchCriteria.StateFullName))
                            queryBuilder = queryBuilder.And(a => a.StateName.Equals(searchCriteria.StateFullName, StringComparison.CurrentCultureIgnoreCase));
                        if (searchCriteria.County.HasValue)
                            queryBuilder = queryBuilder.And(a => a.County == searchCriteria.County.Value);
                        if (!string.IsNullOrWhiteSpace(searchCriteria.CountyFullName))
                            queryBuilder = queryBuilder.And(a => a.CountyName.Equals(searchCriteria.CountyFullName, StringComparison.CurrentCultureIgnoreCase));
                        if (!string.IsNullOrWhiteSpace(searchCriteria.Township))
                            queryBuilder = queryBuilder.And(a => a.Township == searchCriteria.Township);
                        // and so on...for another 10 parameters
                        theQuery = theQuery.Or(queryBuilder.Expand());
                    }
                    // this is where I get error after 12k to 15k criterias have been processed
                    var searchQuery = context.ViewInSqlDatabase.AsExpandable().Where(theQuery).Distinct().ToList();
                    foreach (var query in searchQuery)
                    {
                        var newResultItem = SearchResult.Create(query, fieldSettings); // POCO object with no relation to database
                        if (!results.Contains(newResultItem))
                            results.Add(newResultItem);
                    }

                    skipCount += recordsToProcessInOneBatch;
                }
            }

            return results.Distinct().OrderBy(a => a.State).ThenBy(a => a.County).ThenBy(a => a.Township).ToList();
}

1 个答案:

答案 0 :(得分:0)

Fourat是正确的,您可以将查询修改为context.SearchResults.Where(x => ((x.a == 'v1' &&x.b == 'v2') || (x.a = 'v11' &&x.b = 'v21') || (x.a = 'v12' && x.b = 'v22')).Distinct().OrderBy(a => a.State).ThenBy(a => a.County).ThenBy(a => a.Township).ToList();这样做可以使数据库为您和您做出繁重的工作

如果可以的话,我还建议您使用延迟评估而不是强制它进入列表。