Oracle UNDO表空间监控指南

SELECT ts.tablespace_name, 
       ts.status, 
       df.file_name, 
       df.bytes/1024/1024 AS "Size(MB)"
FROM dba_tablespaces ts
JOIN dba_data_files df ON ts.tablespace_name = df.tablespace_name
WHERE ts.contents = 'UNDO';

SELECT a.tablespace_name,
       ROUND(a.bytes/1024/1024/1024,0) "Total(GB)",
       ROUND((a.bytes-b.bytes)/1024/1024/1024,0) "Used(GB)",
       ROUND(b.bytes/1024/1024/1024,0) "Free(GB)",
       ROUND(((a.bytes-b.bytes)/a.bytes)*100,2) "Used%"
FROM (SELECT tablespace_name, SUM(bytes) bytes 
      FROM dba_data_files GROUP BY tablespace_name) a,
     (SELECT tablespace_name, SUM(bytes) bytes 
      FROM dba_free_space GROUP BY tablespace_name) b
WHERE a.tablespace_name = b.tablespace_name
AND a.tablespace_name IN ('UNDOTBS1','UNDOTBS2');

SELECT usn, 
       ROUND(rssize/1024/1024,2) "Undo Size(MB)",
       wrcount "Write Count",
       optcnt "Optimal Count",
       expcnt "Expired Count",
       unexpcnt "Unexpired Count"
FROM v$undostat;

SELECT TO_CHAR(BEGIN_TIME, 'MM/DD/YYYY HH24:MI:SS') BEGIN_TIME,
       TUNED_UNDORETENTION
FROM V$UNDOSTAT;

SELECT ur undo_retention, 
       dbs db_block_size,
       ROUND((ur * (ups * dbs)) / 1024 / 1024,2) "Required(MB)"
FROM (SELECT value as ur FROM v$parameter WHERE name = 'undo_retention'),
     (SELECT (sum(undoblks) / sum(((end_time - begin_time) * 86400))) ups FROM v$undostat),
     (SELECT value as dbs FROM v$parameter WHERE name = 'db_block_size');