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4 Replies Latest reply: Jan 17, 2013 5:52 AM by oraman RSS

Howto simulate archive log gap

oraman Newbie
Currently Being Moderated
hi all,

I use oracle 11g active dataguard with phisical standby and dgmgrl (maximum performance mode).

for training purposes I would like to simulate archive log gap on standby db.

I tried this:

on primary:
alter system set log_archive_dest_2='' scope=both;
alter system set log_archive_dest_state_2='defer' scope=both;

on standby:
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
shutdown immediate

now I do a few log switches on primary - a few archive logs come up (sequence 58,59), I remove them manually, it looks now like this:
-rw-r----- 1 oracle oinstall 18703360 14. Jan 16:19 o1_mf_1_57_8h88jtm8_.arc
-rw-r----- 1 oracle oinstall 99328 14. Jan 16:28 o1_mf_1_60_8h8911n9_.arc
-rw-r----- 1 oracle oinstall 19968 14. Jan 16:29 o1_mf_1_61_8h8929bt_.arc

on standby:
startup open read only
alter database recover managed standby database using current logfile nodelay disconnect;

so on primary archlogs 58,59 are not there but on standby they appear after startup:
-rw-r----- 1 oracle oinstall 18703360 14. Jan 16:19 o1_mf_1_57_8h88jtn6_.arc
-rw-r----- 1 oracle oinstall 146432 14. Jan 16:48 o1_mf_1_58_8h8b77vg_.arc
-rw-r----- 1 oracle oinstall 259072 14. Jan 16:48 o1_mf_1_59_8h8b72vd_.arc
-rw-r----- 1 oracle oinstall 99328 14. Jan 16:48 o1_mf_1_60_8h8b6y03_.arc
-rw-r----- 1 oracle oinstall 19968 14. Jan 16:48 o1_mf_1_61_8h8b6xxw_.arc

It looks like redo log shipment is independent from archivelogs on primary db!?

what additional steps are required to simulate a gap?

thanks in advance!
  • 1. Re: Howto simulate archive log gap
    mseberg Guru
    Currently Being Moderated
    Hello;

    Defer the remote archive destination on primary

    SQL> alter system set log_archive_dest_state_2=defer;

    Then perform several log switches on the primary.

    Option 2

    Shutdown the listener on the standby

    Option 3

    Change the password on the Primary

    Option 4

    Change the tnsnames on the primary for the standby

    Option 5

    Unplug the network cable on the standby

    Best Regards

    mseberg

    Edited by: mseberg on Jan 14, 2013 11:57 AM
  • 2. Re: Howto simulate archive log gap
    oraman Newbie
    Currently Being Moderated
    Ok, when I break down the network connection, of course the new archivelogs are not on the standby site. however after establishing the connection they are on the standby site even when I deleted them on primary.

    It looks like dataguard is too intelligent to be fooled.

    I thought it were possible to disturb it somehow that archivelogs are copied to the standby site, so the query
    select * from v$archive_gap
    would output some rows even after reestablishing the connection.
  • 3. Re: Howto simulate archive log gap
    mseberg Guru
    Currently Being Moderated
    Understood.

    Have never trusted v$archive_gap

    Try this :

    http://www.visi.com/~mseberg/data_guard/monitor_data_guard_transport.html

    Another thought is to DEFER and then move the archive on the primary and see it that creates a gap.

    Best Regards

    mseberg
  • 4. Re: Howto simulate archive log gap
    oraman Newbie
    Currently Being Moderated
    thank you it helped me a lot

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