Question

为什么IR1需要全扫描？

table=INTR
alias=IR1
access=FULL SCAN

IR2不需要全面扫描：

table=INTR
alias=IR2
access=INDEX PRED

完全相同的加入：

EXPLAIN PLAN FOR SELECT *
FROM DTMS.INTR_SUB s
JOIN DTMS.INTR ir1 ON s.CLASS_1 = ir1.CLASS
JOIN DTMS.NDC_INDEX n1 ON ir1.KDC1 = n1.KDC1 
JOIN DTMS.INTR ir2 ON s.CLASS_2 = ir2.CLASS
JOIN DTMS.NDC_INDEX n2 ON ir2.KDC1 = n2.KDC1 
WHERE n1.NDC = 378204701 AND n2.NDC = 378204701

以下是我的索引：

 s INDEX 1 CLASS_1
 s INDEX 2 CLASS_2
 ir PRIMARY KEY(KDC1,CLASS)
 ir INDEX (CLASS)

如果我在s.CLASS_1上禁用索引（通过添加0）， HSQL决定它可以为IR1使用相同的索引和IR2。

 alias=S
 access=FULL SCAN

 table=INTR
 alias=IR2
 access=INDEX PRED

 table=INTR
 alias=IR1
 access=INDEX PRED

 EXPLAIN PLAN FOR SELECT *
 FROM DTMS.INTR_SUB s
 JOIN DTMS.INTR ir1 ON s.CLASS_1+0 = ir1.CLASS
 JOIN DTMS.NDC_INDEX n1 ON ir1.KDC1 = n1.KDC1 
 JOIN DTMS.INTR ir2 ON s.CLASS_2 = ir2.CLASS
 JOIN DTMS.NDC_INDEX n2 ON ir2.KDC1 = n2.KDC1 
 WHERE n1.NDC = 378204701 AND n2.NDC = 378204701

这是架构。在数据库管理器中，我不得不复制/粘贴三个创建表分别创建表：

 CREATE SCHEMA DTMS AUTHORIZATION SA;

 SET SCHEMA DTMS;

 CREATE CACHED TABLE DTMS.INTR(KDC1 NUMERIC(5) NOT NULL,CLASS NUMERIC(5) NOT NULL,PRIMARY KEY(KDC1,CLASS));

 CREATE CACHED TABLE DTMS.NDC_INDEX(NDC NUMERIC(11) PRIMARY KEY,KDC1 NUMERIC(5) NOT NULL,KDC2 NUMERIC(2) NOT NULL,KDC3 NUMERIC(3) NOT NULL,ACTIVITY_CODE NUMERIC(1) NOT NULL,ROUTE_ABRV CHARACTER(2) NOT NULL);

 CREATE CACHED TABLE DTMS.INTR_SUB(CLASS_1 NUMERIC(5) NOT NULL,DURATION_1 NUMERIC(3) NOT NULL,SCHEDULE_1 NUMERIC(3) NOT NULL,ACTIVITY_CODE_1 NUMERIC(1) NOT NULL,CLASS_2 NUMERIC(5) NOT NULL,DURATION_2 NUMERIC(3) NOT NULL,SCHEDULE_2 NUMERIC(3) NOT NULL,ACTIVITY_CODE_2 NUMERIC(1) NOT NULL,ONSET_CODE NUMERIC(1) NOT NULL,SEVERITY_CODE NUMERIC(1) NOT NULL,DOC_CODE NUMERIC(1) NOT NULL,MGMT_CODE NUMERIC(1) NOT NULL,FILE_POS NUMERIC(15) NOT NULL);

 CREATE INDEX INTR_SUB_CLASS_1 ON DTMS.INTR_SUB(CLASS_1);
 CREATE INDEX INTR_SUB_CLASS_2 ON DTMS.INTR_SUB(CLASS_2);
 CREATE INDEX INTR_CLASS ON DTMS.INTR(CLASS);

Answer 1

此问题已在2.2.5中修复，报告如下。

  ][range variable 2                                 
  join type=INNER                                    
  table=INTR                                         
  alias=IR1                                          
  access=INDEX PRED                                  

  ][range variable 4                                 
  join type=INNER                                    
  table=INTR                                         
  alias=IR2                                          
  access=INDEX PRED

关于DatabaseManager的使用，您可以将整个模式及其表和索引定义为单个SQL语句。分号仅在结尾处使用。此语句由DatabaseManager完全执行，因为它是SQL中的单个CREATE SCHEMA语句：

CREATE SCHEMA DTMS AUTHORIZATION SA
 CREATE CACHED TABLE DTMS.INTR(KDC1 NUMERIC(5) NOT NULL,CLASS NUMERIC(5) NOT NULL,PRIMARY KEY(KDC1,CLASS))
 CREATE CACHED TABLE DTMS.NDC_INDEX(NDC NUMERIC(11) PRIMARY KEY,KDC1 NUMERIC(5) NOT NULL,KDC2 NUMERIC(2) NOT NULL,KDC3 NUMERIC(3) NOT NULL,ACTIVITY_CODE NUMERIC(1) NOT NULL,ROUTE_ABRV CHARACTER(2) NOT NULL)
 CREATE CACHED TABLE DTMS.INTR_SUB(CLASS_1 NUMERIC(5) NOT NULL,DURATION_1 NUMERIC(3) NOT NULL,SCHEDULE_1 NUMERIC(3) NOT NULL,ACTIVITY_CODE_1 NUMERIC(1) NOT NULL,CLASS_2 NUMERIC(5) NOT NULL,DURATION_2 NUMERIC(3) NOT NULL,SCHEDULE_2 NUMERIC(3) NOT NULL,ACTIVITY_CODE_2 NUMERIC(1) NOT NULL,ONSET_CODE NUMERIC(1) NOT NULL,SEVERITY_CODE NUMERIC(1) NOT NULL,DOC_CODE NUMERIC(1) NOT NULL,MGMT_CODE NUMERIC(1) NOT NULL,FILE_POS NUMERIC(15) NOT NULL)
 CREATE INDEX INTR_SUB_CLASS_1 ON DTMS.INTR_SUB(CLASS_1)
 CREATE INDEX INTR_SUB_CLASS_2 ON DTMS.INTR_SUB(CLASS_2)
 CREATE INDEX INTR_CLASS ON DTMS.INTR(CLASS);

HSQL 2.2.4，查询计划错误

1 个答案: