If the query includes a join , the optimizer must determine the join plan hash , sort merge , or nested loop , and the order in which tables are evaluated or joined 如果該查詢包含了連接,那么優(yōu)化器就必須確定連接計(jì)劃( hash 、 sort merge或nested loop ) ,以及評(píng)估或連接表的次序。
Join plan directives that force optimizer to use the designated join method to join tables in the query , either nested loop join , sort merge join , or dynamic hash join 連接計(jì)劃指示,強(qiáng)制優(yōu)化器使用指定的連接方法來(lái)連接查詢中的表,要么是嵌套循環(huán)連接、分類合并連接,要么是動(dòng)態(tài)哈希連接。
For detecting - analyzing method based on snapshot difference , we implement these snapshot differential algorithm : sort merge algorithm , partition hash algorithm and window algorithm . for detecting - analyzing method based on log , we discuss the analyzing method of log on two relation database systems - oracle and sql server 對(duì)基于快照差分的檢測(cè)分析方法,我們實(shí)現(xiàn)了三種快照差分算法: sortmefge算法、 partitionhash算法和wndow算法;對(duì)基于日志的檢測(cè)分析方法,討論了oracle和sqlserver兩種關(guān)系數(shù)據(jù)庫(kù)的日志分析方法。