• Oracle-DG疑问,什么情况下主库会发出一个会话连接备库


    一、疑问,什么情况下主库会发出一个会话连接备库

    可以根据上述问题,进行一定猜测。

    例如,主库启动时,远程归档线程自动发出远程连接dg备库的请求;

    以及远程归档线程状态参数,defer,enable切换时会尝试发起新的连接;

    二、测试

    2.1 主备连接正常,主库shutdown immediate

    Primary
    SQL> shutdown immediate;
    
    Standby
    ps -ef|grep LOCAL=NO  之前有来自主库远程发起的5个session,均断开
    dg_alert
    2021-04-20T07:53:39.624556+08:00
    RFS[13]: Assigned to RFS process (PID:51957)
    RFS[13]: Possible network disconnect with primary database
    其中51957 是其中一个主库远程发起session 在备库主机上的pid

    2.2 主备连接正常,主库startup

    Primary

    SQL> startup

    DB_alert

    2021-04-20T08:00:48.636757+08:00
    TT02: Standby redo logfile selected for thread 1 sequence 98 for destination LOG_ARCHIVE_DEST_2
    2021-04-20T08:00:48.761592+08:00
    ARC1: Standby redo logfile selected for thread 1 sequence 97 for destination LOG_ARCHIVE_DEST_2



    Standby

    $ ps -efmT|grep LOCAL=NO
    oracle 54578
    oracle 54580
    oracle 54582

    DG_ALERT

    2021-04-20T08:00:48.599128+08:00
    Primary database is in MAXIMUM PERFORMANCE mode
    RFS[14]: Assigned to RFS process (PID:54578)
    RFS[14]: Selected log 4 for T-1.S-98 dbid 1594123398 branch 1066342665
    2021-04-20T08:00:48.745723+08:00
    RFS[15]: Assigned to RFS process (PID:54580)
    RFS[15]: Selected log 5 for T-1.S-97 dbid 1594123398 branch 1066342665
    2021-04-20T08:00:48.851883+08:00
    Recovery: global flush, serial recovery

    主库启动时,远程归档线程会连接备库,备库RFS进程接收归档信息进行备库本地化存储归档日志。

    2.3 备库kill远程会话,关闭dg监听

    备库
    $ ps -ef|grep LOCAL=NO
    oracle     3097      1  0 05:07 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     3099      1  0 05:07 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     3101      1  0 05:07 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     3103      1  0 05:07 ?        00:00:00 oraclec12 (LOCAL=NO)
    
    
    SQL> select s.sid,s.serial#,p.program,s.username,p.username,p.background,s.program,s.LAST_CALL_ET,s.LOGON_TIME,s.status 
     from v$process p,v$session s where p.addr=s.paddr and p.spid in(3097,3099,3101,3103);
           SID    SERIAL# PROGRAM                   USERNAME   USERNAME   BA PROGRAM                   LAST_CALL_ET LOGON_TIME   STATUS
    ---------- ---------- ------------------------- ---------- ---------- -- ------------------------- ------------ ------------ ----------------
            51      18042 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)               9 09-MAR-21    INACTIVE
            49      51581 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             853 09-MAR-21    INACTIVE
            50      45678 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             849 09-MAR-21    INACTIVE
            47       5930 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)               0 09-MAR-21    INACTIVE
    
    主库
    SQL> shutdown immediate;
    备库
    远程session 都断开连接!
    备库$lsnrctl stop
    
    主库
    SQL> startup
    select  DEST_NAME , STATUS , RECOVERY_MODE from v$archive_dest_status where dest_name='LOG_ARCHIVE_DEST_2';
    DEST_NAME            STATUS             RECOVERY_MODE
    -------------------- ------------------ ---------------
    LOG_ARCHIVE_DEST_2   ERROR              IDLE
    
    
    备库
    SQL> host lsnrctl start
    $ ps -ef|grep -v grep|grep LOCAL=NO|wc -l
    0
    
    alter system set log_archive_dest_state_2=defer;
    alter system set log_archive_dest_state_2=enable;
    
    
    备库listener
    TIMESTAMP * CONNECT DATA [* PROTOCOL INFO] * EVENT [* SID] * RETURN CODE
    WARNING: Subscription for node down event still pending
    09-MAR-2021 05:28:48 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=c12)(USER=oracle))(COMMAND=status)(ARGUMENTS=64)(SERVICE=LISTENER)(VERSION=203424000)) * status * 0
    2021-03-09T05:31:30.969614+08:00
    09-MAR-2021 05:31:30 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle@c11)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54711)) * establish * orcldg * 0
    09-MAR-2021 05:31:30 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle@c11)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54712)) * establish * orcldg * 0
    2021-03-09T05:31:32.030043+08:00
    09-MAR-2021 05:31:32 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54713)) * establish * orcldg * 0
    09-MAR-2021 05:31:32 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54714)) * establish * orcldg * 0
    2021-03-09T05:31:33.086332+08:00
    09-MAR-2021 05:31:33 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54715)) * establish * orcldg * 0
    09-MAR-2021 05:31:33 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54716)) * establish * orcldg * 0
    09-MAR-2021 05:31:33 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle@c11)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54717)) * establish * orcldg * 0
    09-MAR-2021 05:31:33 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54719)) * establish * orcldg * 0
    09-MAR-2021 05:31:33 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcldg)(CID=(PROGRAM=oracle@c11)(HOST=c11)(USER=oracle))) * (ADDRESS=(PROTOCOL=tcp)(HOST=10.0.0.98)(PORT=54718)) * establish * orcldg * 0
    
    $ ps -ef|grep LOCAL=NO|grep -v grep
    oracle     4874      1  0 05:31 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     4876      1  0 05:31 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     4878      1  0 05:31 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     4880      1  0 05:31 ?        00:00:00 oraclec12 (LOCAL=NO)
    oracle     4882      1  0 05:31 ?        00:00:00 oraclec12 (LOCAL=NO)
    也就是说,12C 主备之间存在多个session
    select s.sid,s.serial#,p.program,s.username,p.username,p.background,s.program,s.LAST_CALL_ET,s.LOGON_TIME,s.status 
     from v$process p,v$session s where p.addr=s.paddr and p.spid in(4874,4876,4878,4880,4882);
           SID    SERIAL# PROGRAM                   USERNAME   USERNAME   BA PROGRAM                   LAST_CALL_ET LOGON_TIME   STATUS
    ---------- ---------- ------------------------- ---------- ---------- -- ------------------------- ------------ ------------ ----------------
            27      44814 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)              55 09-MAR-21    INACTIVE
            56      62720 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)               1 09-MAR-21    INACTIVE
            55      38475 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             115 09-MAR-21    INACTIVE
            28       3511 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             115 09-MAR-21    INACTIVE
            51      40708 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             115 09-MAR-21    INACTIVE
            
    可以发现备库关闭监听,也就代表拒绝新的连接。
    而手工在dg备库kill远程会话,就是将已有的连接kill,因此主备之间连通性断开!

    然后重置远程归档线程参数的状态defer,enable本质是让主库重新发起一次连接dg备库的请求!

    2.4 dg备库取消MRP进程

    alter database recover managed standby database cancel;
    会话还在,主备连通性无改变,只是dg同步中断。

    2.5 dg kill 远程会话

    SQL> alter system kill session '56,62720' immediate;  
    
    主库报Alert
    2021-03-09T05:37:27.839588+08:00
    TT02: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3135)
    TT02: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
    2021-03-09T05:37:27.853485+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_4865.trc:
    ORA-03135: 连接失去联系
    Error 3135 for archive log file 2 to 'tns_standby'
    2021-03-09T05:37:27.855995+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_4865.trc:
    ORA-03135: 连接失去联系
    2021-03-09T05:37:27.856095+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_4865.trc:
    ORA-03135: 连接失去联系
    
    
    
    alter system set log_archive_dest_state_2=defer;
    alter system set log_archive_dest_state_2=enable;
    
    SQL> select s.sid,s.serial#,p.program,s.username,p.username,p.background,s.program,s.LAST_CALL_ET,s.LOGON_TIME,s.status from v$process p,v$session s where p.addr=s.paddr and s.PROGRAM='oracle@c11 (TNS V1-V3)';
           SID    SERIAL# PROGRAM                   USERNAME   USERNAME   BA PROGRAM                   LAST_CALL_ET LOGON_TIME   STATUS
    ---------- ---------- ------------------------- ---------- ---------- -- ------------------------- ------------ ------------ ----------------
            60      28802 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)              34 09-MAR-21    INACTIVE
            56      17436 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)               1 09-MAR-21    INACTIVE
            55      38475 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)             481 09-MAR-21    INACTIVE
    ALTER DATABASE RECOVER MANAGED STANDBY DATABASE archivelog DISCONNECT FROM SESSION;
    alter database recover managed standby database cancel;
    
    
    recover managed standby database disconnect from session;
    
    SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING ARCHIVED LOGFILE DISCONNECT;
    
    MRP0            WAIT_FOR_LOG      
    
           SID    SERIAL# PROGRAM                   USERNAME   USERNAME   BA PROGRAM                   LAST_CALL_ET LOGON_TIME   STATUS
    ---------- ---------- ------------------------- ---------- ---------- -- ------------------------- ------------ ------------ ----------------
            55      57549 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)              13 09-MAR-21    INACTIVE
            56      17436 oracle@c12                PUBLIC     oracle        oracle@c11 (TNS V1-V3)               1 09-MAR-21    INACTIVE

    上述问题,是我们重置参数修复的,新的问题又来了,备库kill 远程会话,Oracle能自动解决这个问题吗? 会话断开意味着主备连通性不正常,无法传输主库redo!



    1) dg kill session ,primary db alert

    2021-04-20T08:21:50.887515+08:00
    TT02: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3135)
    TT02: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
    2021-04-20T08:21:50.887683+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_10879.trc:
    ORA-03135: 连接失去联系
    Error 3135 for archive log file 2 to 'tns_standby'
    2021-04-20T08:21:50.891152+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_10879.trc:
    ORA-03135: 连接失去联系
    2021-04-20T08:21:50.892138+08:00
    Errors in file /picclife/app/oracle/diag/rdbms/orcl/c11/trace/c11_tt02_10879.trc:
    ORA-03135: 连接失去联系

    2) 查询dg连通性状态

    SQL> select dest_id,error from v$archive_dest;

    DEST_ID ERROR
    ---------- -----------------------------------------------------------------
    2 ORA-03135: connection lost contact

    3)主库dml测试!

    SQL> insert into b values(1);

    1 row created.

    SQL> commit;

    dg 无法查询数据!

    4)primary switch archive log 

    SQL> alter system switch logfile;

    SQL> alter system archive log current;

    主库多次切换归档,但是由于远程归档报错,并未重新发起连接dg的请求!

    SQL> select max(sequence#),thread# from v$archived_log group by thread#;

    MAX(SEQUENCE#) THREAD#
    -------------- ----------
    102 1

    并且dg配置了fal server 追gap的情况未出现,因为陷入了一个思维陷阱!

    dg   sequence 最大 97, gap查询不出数据!

    MAX(SEQUENCE#) THREAD#
    -------------- ----------
    97 1    

    5) wait for 6 minute, 主库再次尝试发出请求,dg 会话,连通性自动恢复正常,请注意关注时间点顺序!

    Primary

    ORA-03135: 连接失去联系
    2021-04-20T08:21:50.892138+08:00


    2021-04-20T08:26:20.347305+08:00
    ALTER SYSTEM ARCHIVE LOG
    2021-04-20T08:26:20.349898+08:00
    Thread 1 cannot allocate new log, sequence 101
    Checkpoint not complete
    Current log# 1 seq# 100 mem# 0: /picclife/app/oracle/oradata/orcl/redo01.log
    2021-04-20T08:26:22.826568+08:00
    Thread 1 advanced to log sequence 101 (LGWR switch)
    Current log# 2 seq# 101 mem# 0: /picclife/app/oracle/oradata/orcl/redo02.log
    2021-04-20T08:26:22.838124+08:00
    Archived Log entry 192 added for T-1.S-100 ID 0x5f054486 LAD:1
    2021-04-20T08:26:22.843289+08:00
    ALTER SYSTEM ARCHIVE LOG
    2021-04-20T08:26:22.848645+08:00
    Thread 1 advanced to log sequence 102 (LGWR switch)
    Current log# 3 seq# 102 mem# 0: /picclife/app/oracle/oradata/orcl/redo03.log
    2021-04-20T08:26:22.851459+08:00
    Archived Log entry 193 added for T-1.S-101 ID 0x5f054486 LAD:1
    2021-04-20T08:26:23.299206+08:00
    ALTER SYSTEM ARCHIVE LOG
    2021-04-20T08:26:23.301270+08:00
    Thread 1 cannot allocate new log, sequence 103
    Checkpoint not complete
    Current log# 3 seq# 102 mem# 0: /picclife/app/oracle/oradata/orcl/redo03.log
    2021-04-20T08:26:25.863465+08:00
    Thread 1 advanced to log sequence 103 (LGWR switch)
    Current log# 1 seq# 103 mem# 0: /picclife/app/oracle/oradata/orcl/redo01.log
    2021-04-20T08:26:25.866709+08:00
    Archived Log entry 194 added for T-1.S-102 ID 0x5f054486 LAD:1
    2021-04-20T08:27:49.298684+08:00
    TT04: Standby redo logfile selected for thread 1 sequence 103 for destination LOG_ARCHIVE_DEST_2
    2021-04-20T08:28:49.448793+08:00
    ARC3: Standby redo logfile selected for thread 1 sequence 98 for destination LOG_ARCHIVE_DEST_2

    Standby

    2021-04-20T08:27:49.287742+08:00
    Primary database is in MAXIMUM PERFORMANCE mode
    RFS[16]: Assigned to RFS process (PID:56268)
    RFS[16]: Selected log 5 for T-1.S-103 dbid 1594123398 branch 1066342665
    2021-04-20T08:28:49.348064+08:00
    RFS[17]: Assigned to RFS process (PID:56328)
    RFS[17]: Opened log for T-1.S-100 dbid 1594123398 branch 1066342665
    2021-04-20T08:28:49.353374+08:00
    RFS[18]: Assigned to RFS process (PID:56330)
    RFS[18]: Opened log for T-1.S-99 dbid 1594123398 branch 1066342665
    2021-04-20T08:28:49.361200+08:00
    Archived Log entry 17 added for thread 1 sequence 99 rlc 1066342665 ID 0x5f054486 LAD2 :
    2021-04-20T08:28:49.391236+08:00
    Archived Log entry 18 added for thread 1 sequence 100 rlc 1066342665 ID 0x5f054486 LAD2 :
    RFS[18]: Opened log for T-1.S-101 dbid 1594123398 branch 1066342665
    RFS[17]: Opened log for T-1.S-102 dbid 1594123398 branch 1066342665
    2021-04-20T08:28:49.403222+08:00
    Archived Log entry 19 added for thread 1 sequence 101 rlc 1066342665 ID 0x5f054486 LAD2 :
    2021-04-20T08:28:49.407801+08:00
    Archived Log entry 20 added for thread 1 sequence 102 rlc 1066342665 ID 0x5f054486 LAD2 :
    2021-04-20T08:28:49.434004+08:00
    RFS[19]: Assigned to RFS process (PID:56332)
    RFS[19]: Selected log 4 for T-1.S-98 dbid 1594123398 branch 1066342665
    2021-04-20T08:28:49.462006+08:00

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  • 原文地址:https://www.cnblogs.com/lvcha001/p/14679523.html
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