Reorgchk:重组检查，是否需要重组。
判断表或索引是否需要重组，有2种方法：1.通过reorgchk工具 reorgchk工具利用8个公式（3个表公式，5个索引公式），如果表统计结果F1，F2或F3标记为*，则改表需要重组。如果索引统计结果F4-F8有*标记，则索引需要重组。db2 reorgchk on schema SYSTOOLSTable statistics:F1: 100 * OVERFLOW / CARD < 5F2: 100 * (Effective Space Utilization of Data Pages) > 70F3: 100 * (Required Pages / Total Pages) > 80Index statistics:F4: CLUSTERRATIO or normalized CLUSTERFACTOR > 80F5: 100 * (Space used on leaf pages / Space available on non-empty leaf pages) > MIN(50, (100 - PCTFREE))F6: (100 - PCTFREE) * (Amount of space available in an index with one less level / Amount of space required for all keys) < 100F7: 100 * (Number of pseudo-deleted RIDs / Total number of RIDs) < 20 F8: 100 * (Number of pseudo-empty leaf pages / Total number of leaf pages) < 20
2.通过sysibmadm.snaptab管理视图（只能检查表，索引的检查仍需要reorgchk）。（需要打开实例监控器开关 update dbm cfg using dft_mon_table on，重启实例生效）
如果发现overflow_access与rows_read比例高于3%，则需要对表进行重组。
db2 "select substr(TABNAME,1,18) as TABNAME,ROWS_READ,OVERFLOW_ACCESSES from sysibmadm.snaptab where (ROWS_READ>999) and ((OVERFLOW_ACCESSES*100)/(ROWS_READ+1)>3)" TABNAME ROWS_READ OVERFLOW_ACCESSES ------------------ -------------------- -------------------- T1 10004 3864
对所有表和索引执行reorgchk:
db2 reorgchk current statistics on table all
调用函数对所有表或索引执行reorgchk:
db2 "call SYSPROC.REORGCHK_TB_STATS(‘T‘,‘ALL‘)"| grep "*" | awk ‘{print $1, $2}‘ > reorgchk.outdb2 "call SYSPROC.REORGCHK_IX_STATS(‘T‘,‘ALL‘)"| grep "*" | awk ‘{print $1, $2}‘ >> reorgchk.out ------------------------------------------------------------------
reorg：重组，减少表和索引在物理存储上的碎片。
reorg重组分为表重组和索引重组。表重组支持：离线重组和在线重组。离线表重组：也称classic reorg,支持allow read access(默认选项)，表示重组时其他应用可以读取数据。allow no access选项，表示重组过程中不允许访问改表。离线表重粗采用影子拷贝方法，即创建一份原始数据的副本，在影子拷贝中进行数据reorg，reorg结束后替换源表数据。默认情况下，数据拷贝会在原表空间进行，也可以指定USE选项，在指定临时表空间进行。reorg过程中，会记录事务日志，当出现异常时可以通过日志进行恢复。离线reorg最多包含4个阶段：a.scan-sort:根据reorg指定的索引对表数据进行扫描，排序 （如果没指定索引，表数据重组时不关心顺序）b.build:根据第一阶段的结果进行表数据构建c.replace:用于新数据替换原有数据d.index rebuild:基于新数据，重建索引可以用多种方式检查reorg是否完成：
1.通过sysibmadm.snaptab检查（要求dft_mon_table实例监控器开关打开）db2 "select substr(tabname,1,15) as tabname,substr(tabschema,1,15) as tabschema,substr(reorg_type,1,50) as reorg_type,reorg_status,reorg_completion,dbpartitionnum from sysibmadm.snaptab_reorg" TABNAME TABSCHEMA REORG_TYPE REORG_STATUS REORG_COMPLETION DBPARTITIONNUM --------------- --------------- -------------------------------------------------- ------------ ---------------- -------------- STAFF DB2INST2 RECLUSTER+OFFLINE+ALLOW_READ+TABLESCAN+DATAONLY COMPLETED SUCCESS 0
Reorg Index = 1 Reorg Tablespace = 1 Start Time = 08/14/2014 12:19:32.574580 Reorg Phase = 4 - Index Recreate Max Phase = 4 Phase Start Time = 08/14/2014 12:19:33.026445 Status = Completed Current Counter = 0 Max Counter = 0 Completion = 0 End Time = 08/14/2014 12:19:33.315408
3.通过db2pd reorg选项获得当前正在执行和近期完成的重组信息：
db2pd -d sample -reorgDatabase Partition 0 -- Database SAMPLE -- Active -- Up 0 days 02:23:38 -- Date 2014-08-14-12.28.09.413756Table Reorg Information:Address TbspaceID TableID PartID MasterTbs MasterTab TableName Type IndexID TempSpaceID0x00007F98399BA328 2 15 n/a n/a n/a STAFF Offline 1 1 Table Reorg Stats:Address TableName Start End PhaseStart MaxPhase Phase CurCount MaxCount Status Completion0x00007F98399BA328 STAFF 08/14/2014 12:19:32 08/14/2014 12:19:33 08/14/2014 12:19:33 4 IdxRecreat 0 0 Done 0
4.通过list history reorg all for sample获得表或索引重组信息：
Op Obj Timestamp+Sequence Type Dev Earliest Log Current Log Backup ID -- --- ------------------ ---- --- ------------ ------------ -------------- G T 20140814121932 F S0000001.LOG S0000002.LOG ---------------------------------------------------------------------------- Table: "DB2INST2"."STAFF" ---------------------------------------------------------------------------- Comment: REORG INDEX 1 USE 1 Start Time: 20140814121932 End Time: 20140814121933 Status: A ---------------------------------------------------------------------------- EID: 6