Question

用内存优化表替换了一个大表对于某些东西，我对某些东西的反应时间很长它是复合主键
我可以使用主键的唯一方法是搜索特定行（整个PK）
不会将PK用于排序或仅使用复合键的一个组件
从现有数据中调整哈希桶的大小

使用此链接中的语法作为复合主键
Hekaton: Composite Primary Key in create table statement
CREATE TABLE (SQL Server)

CREATE TABLE [dbo].[FTSindex]
(
    [sID] [int] NOT NULL,
    [wordPos] [int] NOT NULL,
    [wordID] [int] NOT NULL,
    [charPos] [int] NOT NULL,

INDEX [ix_wordID_MO_2] NONCLUSTERED HASH 
(
    [wordID]
)WITH ( BUCKET_COUNT = 524288),
CONSTRAINT [pk_FTSindexMO_2] PRIMARY KEY NONCLUSTERED HASH 
(
    [sID],
    [wordPos]
)WITH ( BUCKET_COUNT = 268435456)
)WITH ( MEMORY_OPTIMIZED = ON , DURABILITY = SCHEMA_ONLY )

select top 10 * from [FTSindex] where [sID] = 100
-- runs in 0 seconds 
-- Index Seek on ix_wordID_MO_2 
-- it is NOT using the PRIMARY KEY pk_FTSindexMO_2

select top 10 * from [FTSindex] where [wordPos] = 100
-- never finishes (I only waited 10 minutes) 
-- will not even display an execution plan

select top 10 * from [FTSindex] where [sID] = 100 and [wordPos] < 1000
-- never finishes (I only waited 10 minutes) 
-- will not even display an execution plan


select top 10 * from [FTSindex] order by [sID]
-- never finishes (I only waited 10 minutes) 
-- query plan is Table Scan 

select top 10 * from [FTSindex] order by [sID], [wordPos]
-- never finishes (I only waited 10 minutes) 
-- will not even display an execution plan

select top 10 * from [FTSindex] where [wordID] = 100 and [sID] = 856515 
-- runs in 0 seconds
-- Index Seek on ix_wordID_MO_2

select top 10 * from [FTSindex] where [wordID] = 100 and [sID] = 856515  and [wordPos] < 1000
-- never finishes (I only waited 10 minutes) 
-- will not even display an execution plan

select * from [FTSindex] where [sID] = 100  
-- 45 seconds to return 1500 rows 
-- table scan 

select * from [FTSindex] where [sID] = 100  and [wordPos] = 1133 
-- runs in 0 seconds
-- this uses the pk_FTSindexMO_2 
-- this is the only way I could get it to use the primary key

注意原始（非内存优化表）
所有这些查询都在0秒内运行我不是指每个人 ALL在0秒内运行

我认为这总结了我的问题 Troubleshooting Common Performance Problems with Memory-Optimized Hash Indexes

主键上没有使用HASH似乎修复了它

CREATE TABLE [dbo].[FTSindex]
(
    [sID] [int] NOT NULL,
    [wordPos] [int] NOT NULL,
    [wordID] [int] NOT NULL,
    [charPos] [int] NOT NULL,

INDEX [ix_wordID_MO_2] NONCLUSTERED HASH 
(
    [wordID]
)WITH ( BUCKET_COUNT = 524288),
CONSTRAINT [pk_FTSindexMO_2] PRIMARY KEY NONCLUSTERED 
(
    [sID] ASC,
    [wordPos] ASC
)
)WITH ( MEMORY_OPTIMIZED = ON , DURABILITY = SCHEMA_ONLY )

注意到最后我会回到旧的基于磁盘的表格在应用程序使用的实际查询中，优化的内存较慢优化的内存确实加载得更快但是这个表写了一次并且读了很多

Answer 1

散列索引不适用于范围扫描。范围索引是。

内存优化表有一些可怕的响应时间

1 个答案: