1

数据库：火鸟 3.0

此查询用于选择符合特定条件的记录，以检测哪些记录DEVICEID比其他人LAST_TICK知道DEVICEID={INTEGER VALUE}的记录大DEVICEID

这是 SQL 查询：

select 
    a.TABELA, 
    a.DEVICEID,
    (select LAST_TICK from KNOWLEDGE b where b.DEVICEID={INTEGER VALUE} and b.CROSSID=a.DEVICEID and b.TABELA=a.TABELA) as MEU_TICK,
    max(LAST_TICK) as MAX_TICK 
from 
    KNOWLEDGE a 
where 
    a.DEVICEID=a.CROSSID 
group by
    a.TABELA, a.DEVICEID 
having 
    max(LAST_TICK) > (select LAST_TICK from KNOWLEDGE b where b.DEVICEID={INTEGER VALUE} and b.CROSSID=a.DEVICEID and b.TABELA=a.TABELA) 
order by 
    a.TABELA

只有 11 条记录的性能统计；

Plan
PLAN (B INDEX (PK_KNOWLEDGE))
PLAN (B INDEX (PK_KNOWLEDGE))
PLAN SORT (A NATURAL)

------ Performance info ------
Prepare time = 0ms
Execute time = 0ms
Current memory = 36.473.632
Max memory = 36.729.200
Memory buffers = 2.048
Reads from disk to cache = 0
Writes from cache to disk = 0
Fetches from cache = 65

Select Expression
-> Singularity Check
    -> Filter
        -> Table "KNOWLEDGE" as "B" Access By ID
            -> Bitmap
                -> Index "PK_KNOWLEDGE" Unique Scan
Select Expression
-> Singularity Check
    -> Filter
        -> Table "KNOWLEDGE" as "B" Access By ID
            -> Bitmap
                -> Index "PK_KNOWLEDGE" Unique Scan
Select Expression
-> Filter
    -> Aggregate
        -> Sort (record length: 214, key length: 176)
            -> Filter
                -> Table "KNOWLEDGE" as "A" Full Scan

*** 编辑 1：DDL：

CREATE TABLE KNOWLEDGE (
DEVICEID   "INTEGER" NOT NULL /* "INTEGER" = INTEGER */,
TABELA     VARCHAR40 NOT NULL /* VARCHAR40 = VARCHAR(40) */,
CROSSID    "INTEGER" NOT NULL /* "INTEGER" = INTEGER */,
LAST_TICK  "INTEGER" NOT NULL /* "INTEGER" = INTEGER */
);
ALTER TABLE KNOWLEDGE ADD CONSTRAINT PK_KNOWLEDGE PRIMARY KEY (DEVICEID, TABELA, CROSSID);
CREATE INDEX KNOWLEDGE_IDX1 ON KNOWLEDGE (TABELA);
CREATE INDEX KNOWLEDGE_IDX2 ON KNOWLEDGE (DEVICEID, CROSSID);

样本数据：

INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (4, 'PESSOAS', 12, 5);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (5, 'PESSOAS', 12, 5);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (6, 'PESSOAS', 12, 5);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (7, 'PESSOAS', 12, 5);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (8, 'PESSOAS', 12, 5);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 4, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 5, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 6, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (9, 'PESSOAS', 12, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 4, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 5, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 6, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (10, 'PESSOAS', 12, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 4, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 5, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 6, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (11, 'PESSOAS', 12, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 4, 11);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 5, 47);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 6, 118);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 7, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 8, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 9, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 10, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 11, 0);
INSERT INTO KNOWLEDGE (DEVICEID, TABELA, CROSSID, LAST_TICK)
           VALUES (12, 'PESSOAS', 12, 10);

COMMIT WORK;

逻辑细节：

它用于数据同步算法。该知识表包含来自系统中注册的每个设备的知识（Last Update Tick），并将其存储在服务器中。客户端设备连接到服务器并发送更新的记录，服务器更新其知识表以反映这些更改。然后其他客户端设备连接到服务器以获取这些更改并更新其本地数据库。

知识表的逻辑是这样的：

D-嘿服务器，我是设备 4，我想知道有什么新东西适合我吗？

S-K，等等，让我检查一下。嘿数据库服务器，从知识表中获取 DEVICEID 的 LAST_TICK 高于我自己的知识 (CROSSID=DEVICEID) 的所有记录，并将设备自己的知识放入该查询中，以便服务器更容易构建查询对于那些记录。

DB-当然，这是清单

S- 很好，现在从这些表中获取所有那些 update_tick 高于设备 4 知识的记录。

Db-是的，就是这样。

S-嘿设备，获取这些记录并更新它

d-np，完成。谢啦..

使用上面提供的测试数据，无论我们在 {INTEGER VALUE} 中提供什么设备 ID，结果都应该是单行：{ TABELA: "PESSOAS", DEVICEID: 12, MEU_TICK: 5, MAX_TICK: 12 }

4

2 回答 2

0

您可以像这样创建一个 cte：

With cte_base AS (
select distinct LAST_TICK 
from KNOWLEDGE b 
where b.DEVICEID={INTEGER VALUE} and b.CROSSID=a.DEVICEID 
and b.TABELA=a.TABELA
)

select 
    a.TABELA, 
    a.DEVICEID,
    cte_base.LAST_TICK as MEU_TICK,
    max(LAST_TICK) as MAX_TICK 
from 
    KNOWLEDGE a 
where 
    a.DEVICEID=a.CROSSID 
group by
    a.TABELA, a.DEVICEID 
having 
    max(LAST_TICK) > (cte_base.LAST_TICK) 
order by 
    a.TABELA
于 2018-03-23T19:03:08.610 回答
0

一个可能会提高性能的非常简单的更改正在更改

group by
    a.TABELA, a.DEVICEID

至

group by
    a.DEVICEID, a.TABELA

这将允许优化器PK_KNOWLEDGE用于聚合所需的排序。

通过将查询重写为：

with max_tick as (
    select 
       TABELA,
       DEVICEID,
       MAX(LAST_TICK) as MAX_TICK
    from KNOWLEDGE
    where DEVICEID = CROSSID
    group by DEVICEID, TABELA
)
select 
   a.TABELA,
   a.DEVICEID,
   a.MAX_TICK,
   b.LAST_TICK AS MEU_TICK
from max_tick a
inner join KNOWLEDGE b 
   on a.DEVICEID = b.CROSSID AND a.TABELA = b.TABELA and a.MAX_TICK > b.LAST_TICK
where b.DEVICEID = {INTEGER VALUE}
order by a.TABELA

但我不能 100% 确定此查询是否等效，因为您的示例数据没有提供足够的变化来测试它。

于 2018-03-24T09:36:03.590 回答