select nextval for seq_att from SYSIBM.SYSDUMMY1

Operation not allowed for reason code "7" on table "DB2.XXX". SQLSTATE=5701


对表进行任何操作都不被允许，提示SQLSTATE=57016 SQLCODE=-668 ，原因码 "7"的错误：SQL0668N Operation not allowed for reason code "7" on table XXX. 解决方法为：执行命令：reorg table XXX；即可。
参考原文为：
Operation not allowed for reason code reason-code on table table-name.
Explanation: Access to table table-name is restricted. The cause is based on the following reason codes reason-code: 7
The table is in the reorg pending state. This can occur after an ALTER TABLE statement containing a REORG-recommended operation.7
Reorganize the table using the REORG TABLE command (note that INPLACE REORG TABLE is not allowed for a table that is in the reorg pending state).
其中：
reorg table <tablename> 通过重构行来消除“碎片”数据并压缩信息，对表进行重组。
runstats on table <tbschema>.<tbname> 收集表 <tbname> 的统计信息。
reorgchk on table all 确定是否需要对表进行重组，对于对所有表自动执行 runstats 很有用。
>>> reorg 和runstats 都是单个表优化，初始化的命令：
runstats on table administrator.test;
reorg table administrator.test;

转自：http://tting.iteye.com/blog/1555571