Tips:
fnd_lobs表會儲存我們上傳的一些檔案和Form介面“檔案“-“匯出”的檔案。如果不定期清理了話，會出現檔案上傳失敗，或者是匯出按鈕可以點選，但是點選完以後沒有任何反應。這個時候我們應該看下fnd_lobs所屬的表空間APPS_TS_MEDIA是不是已經滿了。我們可以通過以下的命令刪除“匯出”的檔案。
delete fnd_lobs fl WHERE fl.program_name='export';

--檢視資料庫例項狀態
SELECT instance_name, host_name, startup_time, status, database_status
  
 
FROM v$instance;


--檢視資料庫資訊
SELECT NAME, log_mode, open_mode
  FROM v$database a;


--檢視本機監聽器程序
ps -ef|grep lsn|grep -v grep
-e 顯示所有程序。
-f 顯示更完整的程序資訊
-v：顯示不包含匹配文字的所有行。


--檢視控制檔案的狀態
SELECT status, NAME
  FROM v$controlfile;

--檢視redo日記的狀態
SELECT group#, status, TYPE, MEMBER
  FROM v$logfile;

--查看錶空間的狀態
 

SELECT tablespace_name, status
  FROM dba_tablespaces;

--檢視資料檔案的狀態
SELECT NAME, status
  FROM v$datafile;

--檢視無效物件
SELECT owner, object_name, object_type, status
  FROM dba_objects
 WHERE status != 'VALID'
   AND owner != 'SYS'
   AND owner != 'SYSTEM';

--v$resource_limit 資源檢查
SELECT resource_name, initial_allocation,CURRENT_UTILIZATION, max_utilization, limit_value
  
 
FROM v$resource_limit ;

--v$resource_limit 資料庫連線狀態
SELECT COUNT(1)
  FROM v$session a
SELECT sid, serial#, username, program, machine, status
  FROM v$session;

--檢查表空間使用情況
SELECT f.tablespace_name, a.total "total (M)", f.free "free (M)", round((f.free / a.total) * 100) "% Free"
  FROM (SELECT tablespace_name, SUM(bytes / (1024 * 1024)) total
          FROM dba_data_files
         GROUP BY tablespace_name) a,
       (SELECT tablespace_name, round(SUM(bytes / (1024 * 1024))) free
          FROM dba_free_space
         GROUP BY tablespace_name) f
 WHERE a.tablespace_name = f.tablespace_name(+)
 ORDER BY "% Free";

--表空間是否具有自動擴充套件空間
SELECT t.tablespace_name, d.file_name, d.autoextensible, d.bytes, d.maxbytes, d.status
  FROM dba_tablespaces t, dba_data_files d
 WHERE t. tablespace_name = d. tablespace_name
 ORDER BY tablespace_name, file_name

--檢查下一擴充套件與表空間的最大擴充套件值
SELECT a.table_name, a.next_extent, a.tablespace_name
  FROM all_tables a,
       (SELECT tablespace_name, MAX(bytes) AS big_chunk
          FROM dba_free_space
         GROUP BY tablespace_name) f
 WHERE f.tablespace_name = a.tablespace_name
   AND a.next_extent > f.big_chunk
UNION
SELECT a.index_name, a.next_extent, a.tablespace_name
  FROM all_indexes a,
       (SELECT tablespace_name, MAX(bytes) AS big_chunk
          FROM dba_free_space
         GROUP BY tablespace_name) f
 WHERE f.tablespace_name = a.tablespace_name
   AND a.next_extent > f.big_chunk;

--檢查資料庫的等待事件
SELECT sid, event, p1, p2, p3, wait_time, seconds_in_wait
  FROM v$session_wait
 WHERE event NOT LIKE 'SQL%'
   AND event NOT LIKE 'rdbms%';


--查詢前十條效能差的sql 
SELECT *
  FROM (SELECT parsing_user_id executions, sorts, command_type, disk_reads, sql_text
          FROM v$sqlarea
         ORDER BY disk_reads DESC)
 WHERE rownum < 10;

--查詢前十條效能差的sql 
SELECT username, sid, opname, round(sofar * 100 / totalwork, 0) || '%' AS progress, time_remaining, sql_text
  FROM v$session_longops, v$sql
 WHERE time_remaining <> 0
   AND sql_address = address
   AND sql_hash_value = hash_value;


--監控資料庫某使用者在執行什麼SQL 
SELECT sql_text
  FROM v$sqltext t, v$session s
 WHERE t.address = s.sql_address
   AND t.hash_value = s.sql_hash_value
   AND s.machine = 'XXXXX'
    OR username = 'XXXXX' -- 檢視某主機名，或使用者名稱