Sql server 对内存中表的查询比对基于磁盘的表的查询慢

我正在使用一个已经构建的表，我必须将其迁移到内存优化的表。以下是基于磁盘的克隆。两者的结构相同，但基于磁盘的表没有主键，即使

OID

字段不应重复

CREATE TABLE [dbo].[DATA_IM](
    [OID]       [varchar](36) NOT NULL, -- NEWID()
    [YEAR]      [varchar](15) NOT NULL  INDEX hash_sce HASH (YEAR) WITH (BUCKET_COUNT = 128),
    [MONTH]     [varchar](2)  NOT NULL,
    [DEPARTMENT][varchar](30) NOT NULL  INDEX hash_dep  HASH (DEPARTMENT)  WITH (BUCKET_COUNT = 64),
    [ACCOUNT]   [varchar](30) NOT NULL  INDEX hash_acct HASH (ACCOUNT)     WITH (BUCKET_COUNT = 2048),
    [DIM1]      [varchar](30) NULL      INDEX hash_de1  HASH (DIM1) WITH (BUCKET_COUNT = 256),
    [DIM2]      [varchar](30) NULL      INDEX hash_de2  HASH (DIM2) WITH (BUCKET_COUNT = 256),
    [DIM3]      [varchar](30) NULL      INDEX hash_de3  HASH (DIM3) WITH (BUCKET_COUNT = 256),
    [DIM4]      [varchar](30) NULL      INDEX hash_de4  HASH (DIM4) WITH (BUCKET_COUNT = 256),
    [DIM5]      [varchar](30) NULL,
    [CATEGORY]  [varchar](30) NOT NULL INDEX hash_cat HASH (CATEGORY) WITH (BUCKET_COUNT = 256),
    [VALUE]     [numeric](27, 9) NOT NULL,
    [CURRENCY]  [varchar](5)     NULL,
    [ORIGIN]    [varchar](80)   NULL,
    [USERUPD]   [varchar](255)  NULL,
    [DATEUPD]   [datetime]      NULL,
    [NOTE]      [varchar](1000) NULL
)
WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_ONLY)

由于每个内存优化的表都必须至少有一个索引，并且这些列是其他表的外键，因此我在计算了

BUCKET\u计数后对这些列进行了哈希索引，如web上所示：

with cte1 AS (select count(distinct year)        year from data),
     cte2 AS (select count(distinct department)  dept from data)

SELECT  POWER(2, CEILING(LOG(year) / LOG(2))) AS [year],
        POWER(2, CEILING(LOG(dept) / LOG(2))) AS [dept]

FROM cte1, cte2

尽管如此，像使用/out
groupby
的简单选择这样的查询要比针对原始表执行的查询慢。我也尝试过使用非聚集索引和增加桶数，但仍然是一样的

如何加快查询速度？
您应该添加

OPTION (RECOMPILE)

在你的发言结束时：

with cte1 AS (select count(distinct year)        year from data),
     cte2 AS (select count(distinct department)  dept from data)

SELECT  POWER(2, CEILING(LOG(year) / LOG(2))) AS [year],
        POWER(2, CEILING(LOG(dept) / LOG(2))) AS [dept]

FROM cte1, cte2
OPTION (RECOMPILE)

SQL server在创建变量表（无记录）时编译其计划，因此并未对此进行真正的优化。当您用数据填充它时，编译的计划不会得到优化，因为在第一次编译时没有数据

当您添加此选项时，它会告诉SQL Server重新编译，记住现在有数据

它应该快得多。
我建议你在网上问这个问题