[CLUE-Tech] Meanness to my RDBMS

[Dan Harris]

Yes, I've done everything from removing a RAID drive to physically cutting the
network cable on many RDBMS installs.  I've had the best luck with recovery on
Sybase (UNIX) and MSSQL (NT4.0).. Haven't done any disaster recovery exercises
with pgsql yet, but WOW that's great to know.  I am currently in the midst of
planning moving 20 million+ rows from MSSQL to PostgreSQL and that's encouraging
to hear your results.

-Dan Harris

grant wrote:
> 
> Well, I am running PostgreSQL 7.1 RC2.  I decided to be mean to it.  While
> doing a big pile of inserts (50,000) I yanked the power cord out of the
> wall.  Here is what happened.
> 
> On reboot, the OS complained that my EXT2 file system had not been cleanly
> unmounted (duh...)  and proceeded to do an fsck.  Well, it was nasty
> enough to drop me into single user mode and say "Here, moron, you
> unplugged it, fix it yourself!"  So, I ran fsck on the afflicted file
> system.  It complained about bas numbers of references to inodes and
> files, and about data that doesn't really go with anything that it wants
> to stick in lost+found.  I just said yes to everything it asked me about
> fixing.  Then I rebooted and did the same thing for hda5 that I had just
> done for hda7.
> 
> Now that it was up and running, I logged in as postgres (I do not have it
> starting automatically) and started the database.  It took a little longer
> than usual, and looking at the log revealed why.  It told me about which
> transactions it was redoing, and which it was throwing out, and then it
> came up just fine.  When I checked with a select count(*), it was about
> 100 transactions further along than I had expected it to be, and all of
> the data for all of those transactions was intact.  a JFS would have maybe
> saved even more transactions.
> 
> Has anyone tried this with any other DBMS?  I would be interested in how
> well it recovered.
> 
> ______________________________________________________________________________
> 
>                           Your mouse has moved.
>        You must restart Windows for your changes to take effect.
> 
> #!/usr/bin/perl
> print $i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10);
> 
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