【Troubleshooting】EXP-00091 Exporting questionable statistics

[oracle10g@ ~]$ oerr exp 00091
00091, 00000, "Exporting questionable statistics."
// *Cause: Export was able export statistics, but the statistics may not be
// usuable. The statistics are questionable because one or more of
// the following happened during export: a row error occurred, client
// character set or NCHARSET does not match with the server, a query
// clause was specified on export, only certain partitions or
// subpartitions were exported, or a fatal error occurred while
// processing a table.
// *Action: To export non-questionable statistics, change the client character
// set or NCHARSET to match the server, export with no query clause,
// export complete tables. If desired, import parameters can be
// supplied so that only non-questionable statistics will be imported,
// and all questionable statistics will be recalculated.

$ export NLS_LANG=simplified chinese_china.zhs16gbk

exp username/password file=/bakdata/export/day_meta_task_result.dmp log=/bakdata/export/day_meta_task_result.log buffer=100000000 tables=day_meta_task_result query=\"WHERE time\>\'1358524800000\'\"

原因：导出操作能够导出统计信息，但统计信息可能不可用。统计信息是有问题的,因为在导出过程中发生了一个或多个下列的情形: 一行有错误发生, 客户端字符集或者NCHARSET参数和服务器不匹配,在导出中指定了一个query子句,仅仅导出了某些分区或子分区,或者处理表时发生致命错误.
操作：为了导出没有问题的统计信息，更改客户端的字符集设置或ncharset以和服务器匹配，使用没有query子句的导出操作，或导出完整的表。如果需要，可以提供输入参数，以便导入没有问题的统计信息，并且所有存在问题的统计信息将被重新计算。