Oracle CBO术语大集合-阿里云开发者社区

开发者社区> 数据库> 正文

Oracle CBO术语大集合

简介:

最近准备写点Histogram和density相关的文章,先把术语给大家理一理: cardinality (CDN) Legend CBQT - cost-based query transformation JPPD - join predicate push-down OJPPD - old-style (non-cost-based) JPPD FPD - filter push-down PM - predicate move-around CVM - complex view merging SPJ - select-project-join SJC - set join conversion SU - subquery unnesting OBYE - order by elimination OST - old style star transformation ST - new (cbqt) star transformation CNT - count(col) to count(*) transformation JE - Join Elimination JF - join factorization SLP - select list pruning DP - distinct placement qb - query block LB - leaf blocks DK - distinct keys LB/K - average number of leaf blocks per key DB/K - average number of data blocks per key CLUF - clustering factor NDV - number of distinct values Resp - response cost Card - cardinality Resc - resource cost NL - nested loops (join) SM - sort merge (join) HA - hash (join) CPUSPEED - CPU Speed IOTFRSPEED - I/O transfer speed IOSEEKTIM - I/O seek time SREADTIM - average single block read time MREADTIM - average multiblock read time MBRC - average multiblock read count MAXTHR - maximum I/O system throughput SLAVETHR - average slave I/O throughput dmeth - distribution method 1: no partitioning required 2: value partitioned 4: right is random (round-robin) 128: left is random (round-robin) 8: broadcast right and partition left 16: broadcast left and partition right 32: partition left using partitioning of right 64: partition right using partitioning of left 256: run the join in serial 0: invalid distribution method sel - selectivity ptn - partition adop Automatic degree of parallelism TABLE: Table Name ALIAS: Table Alias QBS: Query Block Signature #ROWS: Number of Rows #BLKS: Number of Blocks ARL: Average Row Length COR: Cardinality Original CRD: Cardinality Rounded CCM: Cardinality Computed CNA: Cardinality Non Adjusted AVGLEN: Average Column Length NDV: Number of Distinct Values NULLS: Number of Nulls in Column DEN: Column Density MIN: Minimum Column ValueMAX: Maximum Column Value TYPE: Histogram Type #BKTS: Histogram Buckets UNCOMPBKTS: Histogram Uncompressed Buckets



本文转自maclean_007 51CTO博客,原文链接:http://blog.51cto.com/maclean/1278510

版权声明:本文内容由阿里云实名注册用户自发贡献,版权归原作者所有,阿里云开发者社区不拥有其著作权,亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容,填写侵权投诉表单进行举报,一经查实,本社区将立刻删除涉嫌侵权内容。

分享:
数据库
使用钉钉扫一扫加入圈子
+ 订阅

分享数据库前沿,解构实战干货,推动数据库技术变革

其他文章