利用 10203 事件追蹤 Oracle 區塊清除 (Block Cleanout) 過程

事件用途

Event 10203 可追蹤資料庫區塊清除操作，需在系統層級設定並重啟生效。

啟用步驟

ALTER SYSTEM SET EVENT = '10203 TRACE NAME CONTEXT FOREVER' SCOPE = SPFILE;
SHUTDOWN IMMEDIATE;
STARTUP;
SHOW PARAMETER EVENT;
-- 確認輸出：event = 10203 trace name context forever

追蹤檔輸出範例

Begin cleaning out block ...
Found all committed transactions
Block cleanout record, scn: 0xffff.ffffffff ver: 0x01 opt: 0x02, entries follow...
  itli: 1  flg: 2  scn: 0x0819.0045cd54
Block cleanout under the cache...
Block cleanout record, scn: 0x0819.0045cea1 ver: 0x01 opt: 0x02, entries follow...
  itli: 1  flg: 2  scn: 0x0819.0045cd54
... clean out dump complete.

可觀察 SCN、ITL 狀態、清除模式等細節，協助分析延遲區塊清除造成的效能問題。