Sql server 索引对多where子句SQL的影响
我有一个包含3-400k条目的表 我想对Sql server 索引对多where子句SQL的影响,sql-server,indexing,Sql Server,Indexing,我有一个包含3-400k条目的表 我想对ABCDEFABCDEFAB进行前缀检查。(=A,=AB…) 我已经创建了索引 table.IDX:列上的非唯一哈希索引: TYPE INFORMATION MATCH_PATTERN MATCH_TYPE 我注意到下面的sql请求没有使用创建的索引。 是这样吗?与此相关的任何文件 SELECT COUNT(*) FROM table WHERE table.type = '
ABCDEFABCDEFAB进行前缀检查。(=A,=AB…)
我已经创建了索引
table.IDX:列上的非唯一哈希索引:
TYPE
INFORMATION
MATCH_PATTERN
MATCH_TYPE
我注意到下面的sql请求没有使用创建的索引。
是这样吗?与此相关的任何文件
SELECT COUNT(*)
FROM table
WHERE table.type = 'TYPE'
AND table.info = 'INFO'
AND table.match_type = 'Prefix'
AND (table.match_pattern like 'ABCDEFABCDEFAB%' OR
table.match_pattern = 'ABCDEFABCDEFAB' OR
table.match_pattern = 'ABCDEFABCDEFA' OR
table.match_pattern = 'ABCDEFABCDEF' OR
table.match_pattern = 'ABCDEFABCDE' OR
table.match_pattern = 'ABCDEFABCD' OR
table.match_pattern = 'ABCDEFABC' OR
table.match_pattern = 'ABCDEFAB' OR
table.match_pattern = 'ABCDEFA' OR
table.match_pattern = 'ABCDEF' OR
table.match_pattern = 'ABCDE' OR
table.match_pattern = 'ABCD' OR
table.match_pattern = 'ABC' OR
table.match_pattern = 'AB' OR
table.match_pattern = 'A');
create table aTable (
SERIAL INTEGER,
NAME CHAR(30),
TYPE CHAR(32),
INFORMATION CHAR(32),
MATCH_PATTERN CHAR(40),
MATCH_TYPE TINYINT,
primary key (SERIAL),
foreign key (NAME) references nameTable(name));
create unique index NS.IDX
ON aTable(NAME, TYPE, INFORMATION, MATCH_PATTERN, MATCH_TYPE);
这将利用索引,虽然它很难看,但应该表现良好:
SELECT SUM(CNT) FROM (
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern like 'ABCDEFABCDEFAB%'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABCDEFAB'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABCDEFA'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABCDEF'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABCDE'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABCD'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFABC'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFAB'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEFA'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDEF'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCDE'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABCD'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'ABC'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'AB'
UNION ALL
SELECT COUNT(*) AS CNT FROM table
WHERE type = 'TYPE' AND info = 'INFO' AND match_type = 'Prefix' AND
match_pattern = 'A'
) x;
尝试切换索引列,顺序很重要<代码>类型、信息、匹配类型、匹配模式。另外,
信息
的名称与查询中的名称不同。请回答一个简短的问题:有多少记录与上述条件不匹配?因为如果不太多或不超过所有RAW的50-60%,那么查询优化程序将选择表扫描。请提供DDL+执行计划
@Devart Check over don see execution plan…:(谢谢,我会试试的!