日期:2014-05-16 浏览次数:20600 次
CBQT costbased query transformation JPPD join predicate pushdown OJPPD oldstyle (noncostbased) JPPD FPD filter pushdown PM predicate movearound CVM complex view merging SPJ selectprojectjoin 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 (roundrobin) 128: left is random (roundrobin) 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