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我针对两个大约 130 万行的表的简单连接设置了 AutoQuery。使用内置的迷你分析器来测量 SQL 计时，返回前 100 行（无过滤）的查询需要 3 毫秒，而计数需要额外的 341 毫秒。

是否可以在不获取计数的情况下使用 AutoQuery？我实际上不需要知道完整的计数。

编辑

所以我在想，找出剩余的行数和完整的行数是否会更快。我使用 SSMS 对我们的 MSSQL 数据库进行了测试。

--Generated by ServiceStack
set statistics time on
SELECT COUNT(*) "COUNT(*)" 
FROM "table1" INNER JOIN "table2" ON
("table1"."PrimaryKey" = "table2"."ForeignKey")
set statistics time off

--Skipping 100
set statistics time on
SELECT CASE WHEN EXISTS(
  SELECT "table1"."PrimaryKey"
  FROM "table1" INNER JOIN "table2" ON
  ("table1"."PrimaryKey" = "table2"."ForeignKey")
  ORDER BY "table1"."PrimaryKey" OFFSET 100 ROWS FETCH NEXT 1 ROWS ONLY
) 
THEN CAST(1 AS BIT) 
ELSE CAST(0 AS BIT) END
set statistics time off

--Skipping 100000
set statistics time on
SELECT CASE WHEN EXISTS(
  SELECT "table1"."PrimaryKey"
  FROM "table1" INNER JOIN "table2" ON
  ("table1"."PrimaryKey" = "table2"."ForeignKey")
  ORDER BY "table1"."PrimaryKey" OFFSET 100000 ROWS FETCH NEXT 1 ROWS ONLY
) 
THEN CAST(1 AS BIT) 
ELSE CAST(0 AS BIT) END
set statistics time off

--Skipping 1000000
set statistics time on
SELECT CASE WHEN EXISTS(
  SELECT "table1"."PrimaryKey"
  FROM "table1" INNER JOIN "table2" ON
  ("table1"."PrimaryKey" = "table2"."ForeignKey")
  ORDER BY "table1"."PrimaryKey" OFFSET 1000000 ROWS FETCH NEXT 1 ROWS ONLY
) 
THEN CAST(1 AS BIT) 
ELSE CAST(0 AS BIT) END
set statistics time off

输出：

(1 row(s) affected)

 SQL Server Execution Times:
   CPU time = 203 ms,  elapsed time = 200 ms.

(1 row(s) affected)

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.

(1 row(s) affected)

 SQL Server Execution Times:
   CPU time = 16 ms,  elapsed time = 19 ms.

(1 row(s) affected)

 SQL Server Execution Times:
   CPU time = 203 ms,  elapsed time = 193 ms.
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1 回答 1

3

这不仅仅是您是否需要知道完整计数，而且像 GetLazy()这样的 ServiceClient API 也需要 Total，因此它能够透明地在多个分页查询后面流式传输 AutoQuery 结果。

这以前不是一个明确的选项，但您可以通过添加一个预先填充一个的 ResponseFilter 来避免自动查询查询 Total，例如：

Plugins.Add(new AutoQueryFeature {
    MaxLimit = 100,
    ResponseFilters = {
        ctx => { ctx.Response.Meta["COUNT(*)"] = "0"; }
    }
});

我还刚刚在此提交中添加了对此选项的支持，因此在以后的版本中，您可以使用以下命令删除总计：

Plugins.Add(new AutoQueryFeature {
    MaxLimit = 100,
    IncludeTotal = false,
});

此更改可从 v4.0.61 开始，现在可在 MyGet 上使用。

于 2016-06-21T21:12:10.817 回答