У меня очень простой запрос, который генерируется Entity-Framework, Иногда, когда я пытаюсь запустить этот запрос. Выполняется почти 30 секунд, и я получил тайм-аут Exception.
SELECT TOP (10)
[Extent1].[LinkID] AS [LinkID],
[Extent1].[Title] AS [Title],
[Extent1].[Url] AS [Url],
[Extent1].[Description] AS [Description],
[Extent1].[SentDate] AS [SentDate],
[Extent1].[VisitCount] AS [VisitCount],
[Extent1].[RssSourceId] AS [RssSourceId],
[Extent1].[ReviewStatus] AS [ReviewStatus],
[Extent1].[UserAccountId] AS [UserAccountId],
[Extent1].[CreationDate] AS [CreationDate]
FROM ( SELECT [Extent1].[LinkID] AS [LinkID], [Extent1].[Title] AS [Title], [Extent1].[Url] AS [Url], [Extent1].[Description] AS [Description], [Extent1].[SentDate] AS [SentDate], [Extent1].[VisitCount] AS [VisitCount], [Extent1].[RssSourceId] AS [RssSourceId], [Extent1].[ReviewStatus] AS [ReviewStatus], [Extent1].[UserAccountId] AS [UserAccountId], [Extent1].[CreationDate] AS [CreationDate], row_number() OVER (ORDER BY [Extent1].[SentDate] DESC) AS [row_number]
FROM [dbo].[Links] AS [Extent1]
) AS [Extent1]
WHERE [Extent1].[row_number] > 0
ORDER BY [Extent1].[SentDate] DESC
И код, генерирующий запрос, следующий:
public async Task<IQueryable<TEntity>> GetAsync(Expression<Func<TEntity, bool>> filter = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null)
{
return await Task.Run(() =>
{
IQueryable<TEntity> query = _dbSet;
if (filter != null)
{
query = query.Where(filter);
}
if (orderBy != null)
{
query = orderBy(query);
}
return query;
});
}
Обратите внимание, что когда я удаляю внутренний оператор Select и Where и меняю его на следующий, Query выполняет штраф менее чем за секунду.
SELECT TOP (10)
[Extent1].[LinkID] AS [LinkID],
[Extent1].[Title] AS [Title],
.
.
.
FROM [dbo].[Links] AS [Extent1]
ORDER BY [Extent1].[SentDate] DESC
Любые советы помогут.
UPDATE:
Вот использование выше кода:
var dbLinks = await _uow.LinkRespository.GetAsync(filter, orderBy);
var pagedLinks = new PagedList<Link>(dbLinks, pageNumber, PAGE_SIZE);
var vmLinks = Mapper.Map<IPagedList<LinkViewItemViewModel>>(pagedLinks);
И фильтр:
var result = await GetLinks(null, pageNo, a => a.OrderByDescending(x => x.SentDate));
