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多表连接时,为何走表扫描
图中Q2和Q3的关联字段有WHERE (Q3."LICE_DOC_STATUS" = '2') AND (Q3."REGIE_ID" = '000000000222222') AND (Q1."IF_USED" = '1') AND (Q3."LICENSE_CODE" = Q2."LICENSE_CODE") AND (Q3."CUST_ID" = Q2."CUST_ID")这里连接实际返回结果集行数为0,为何会让Q2... 显示全部
查看其它 30 个回答xu5762173 的回答
回复 12# leo
王大师您好,非常感谢一直的跟进
按照您的建议,在测试环境重建了当前测试环境,目前Q2(rm_license),Q3(rm_license_apply)索引信息如下:
tab unqiue columns
-------------------- ---------- --------------------------------------------------
RM_LICENSE P +LICENSE_CODE+REGIE_ID
RM_LICENSE D +CUST_ID+LICENSE_CODE
-------------------- ---------- --------------------------------------------------
RM_LICENSE_APPLY D +REGIE_ID
RM_LICENSE_APPLY P +APPLY_ID
RM_LICENSE_APPLY D +CUST_ID+LICENSE_CODE
$ db2 "runstats on table db2instt.rm_license_apply on all columns with distribution on all columns and sampled detailed indexes all "
$ db2 "runstats on table db2instt.rm_license on all columns with distribution on all columns and sampled detailed indexes all "
访问计划还是一样
王大师您好,非常感谢一直的跟进
按照您的建议,在测试环境重建了当前测试环境,目前Q2(rm_license),Q3(rm_license_apply)索引信息如下:
tab unqiue columns
-------------------- ---------- --------------------------------------------------
RM_LICENSE P +LICENSE_CODE+REGIE_ID
RM_LICENSE D +CUST_ID+LICENSE_CODE
-------------------- ---------- --------------------------------------------------
RM_LICENSE_APPLY D +REGIE_ID
RM_LICENSE_APPLY P +APPLY_ID
RM_LICENSE_APPLY D +CUST_ID+LICENSE_CODE
$ db2 "runstats on table db2instt.rm_license_apply on all columns with distribution on all columns and sampled detailed indexes all "
$ db2 "runstats on table db2instt.rm_license on all columns with distribution on all columns and sampled detailed indexes all "
访问计划还是一样
