(5)db2expln执行计划输出工具
这个工具将指定语句的执行计划输出到终端屏幕或一个文件。下面举例说明db2expln命令格式和输出如下：-d指定数据库名，-q是一个SQL语句，也可以用-f指定某个保存了SQL的文件。-u可以指定用户名和口令。-t表示输出到终端，-o可以输出到文件。
[db2inst1@aix:/home/db2inst1]#>db2expln -d tpch -q "select count(*) cnt from tpch.part where p_size=30" -g -tIBM DB2 Universal Database SQL and XQUERY Explain Tool******************** DYNAMIC ***************************************==================== STATEMENT ========================================== Isolation Level = Cursor Stability Blocking = Block Unambiguous Cursors Query Optimization Class = 5 Partition Parallel = No --分区间并行未开启 Intra-Partition Parallel = No --分区内并行未开启 SQL Path = "SYSIBM", "SYSFUN", "SYSPROC", "SYSIBMADM", "DB2INST1"Statement: select count(*)cnt from tpch.part where p_size=30Section Code Page = 1208Estimated Cost = 11047.642578 --估计的成本Estimated Cardinality = 1.000000 --估计的基数Access Table Name = TPCH.PART ID = 4,9| #Columns = 0| Skip Inserted Rows| Avoid Locking Committed Data| Currently Committed for Cursor Stability| May participate in Scan Sharing structures| Scan may start anywhere and wrap, for completion| Fast scan, for purposes of scan sharing management| Scan can be throttled in scan sharing management| Relation Scan| | Prefetch: Eligible| Lock Intents| | Table: Intent Share| | Row : Next Key Share| Sargable Predicate(s)| | #Predicates = 1| | Predicate Aggregation| | | Column Function(s)Aggregation Completion| Column Function(s)Return Data to Application| #Columns = 1End of section--图形化的执行计划Optimizer Plan: Rows Operator (ID) Cost 1 n/a RETURN ( 1) 11047.6 | 1 n/a GRPBY ( 2) 11047.6 | 37482.7 n/a TBSCAN ( 3) 11043.7 | 2.00041e+06 n/a Table: TPCH PART 
