Using WireGuard directly offers better performance than using Tailscale. Tailscale does more than WireGuard, so that will always be true. We aim to minimize that gap, and Tailscale generally offers good bandwidth and excellent latency, particularly compared to non-WireGuard VPNs.
執行指令登入到headscale 打開dos, 或是powershell (希望不用做這動作, 不然麻瓜會生氣) ** powershell or cmd run as administrator
cd C:\Program Files\Tailscale
tailscale login --login-server https://headscale.test.com --exit-node=<headscale ip 可為headscale server local ip> --exit-node-allow-lan-access=true
SQL> show parameter undo;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 21600
undo_tablespace string UNDOTBS1
SQL> ALTER SYSTEM SET UNDO_RETENTION = 43200;
SQL>
System altered.
SQL>
# 新增undo tablespace
create undo tablespace UNDOTBS2 datafile '/.../oradata/undotbs02.dbf' size 30000M autoextend on next 100m maxsize unlimited;
#生效
alter system set undo_tablespace = UNDOTBS2 scope=both;
#查看狀態
select tablespace_name, status, count(*) from dba_rollback_segs group by tablespace_name, status;
select status,segment_name from dba_rollback_segs where status not in ('OFFLINE') and tablespace_name='UNDOTBS1';
select tablespace_name, status, count(*) from dba_rollback_segs group by tablespace_name, status;
#確認舊的已是offline , 就可以刪掉舊的
Drop tablespace UNDOTBS1 including contents and datafiles;
#再次查看是否已變成新的undo tablespace
show parameter undo
select tablespace_name tablespace, status, sum(bytes)/1024/1024 sum_in_mb, count(*) counts
from dba_undo_extents
group by tablespace_name, status order by 1,2;
# 以下紅色部分請改為有問題資料表與欄位名稱, 若沒有出現錯誤, 就換下一個欄位(fieldname)試試看
SET TIMING ON
DECLARE
ERROR_1578 EXCEPTION;
ERROR_1555 EXCEPTION;
ERROR_22922 EXCEPTION;
PRAGMA EXCEPTION_INIT(ERROR_1578, -1578);
PRAGMA EXCEPTION_INIT(ERROR_1555, -1555);
PRAGMA EXCEPTION_INIT(ERROR_22922, -22922);
N NUMBER;
BEGIN
FOR ROW IN (SELECT ROWID, fieldname FROM user.table)
LOOP
BEGIN
N:=DBMS_LOB.INSTR(ROW.fieldname, HEXTORAW('889911'));
EXCEPTION
WHEN ERROR_1578 THEN
INSERT INTO CORRUPTED_ROWS VALUES (ROW.ROWID, 1578);
COMMIT;
WHEN ERROR_1555 THEN
INSERT INTO CORRUPTED_ROWS VALUES (ROW.ROWID, 1555);
COMMIT;
WHEN ERROR_22922 THEN
INSERT INTO CORRUPTED_ROWS VALUES (ROW.ROWID, 22922);
COMMIT;
END;
END LOOP;
END;
/
接下來查詢是否真有問題資料
SELECT * FROM CORRUPTED_ROWS;
#執行以下這行指令應該要出錯
SELECT fieldname FROM user.table WHERE ROWID IN (SELECT CORRUPTED_ROWID FROM CORRUPTED_ROWS);
清空有問題的資料欄位
#若欄位型態是clob就用empty_clob(), 若為blob,就改成empty_blob(), 有幾個欄位出問題就清空幾個
update xxx.table set fieldname = empty_clob()where ROWID IN (SELECT CORRUPTED_ROWID FROM CORRUPTED_ROWS);
若不敢清空, 可以跳過有問題的資料備份
exp system@yourinstance BUFFER=81920 file=/tmp/backup.dmp tables=user.table QUERY=\"WHERE rowid NOT IN \(SELECT CORRUPTED_ROWID FROM CORRUPTED_ROWS\)\"
