On 9/1/2004 10:29 AM, Joe Conway wrote:
> Jeff wrote:
>>
>> On Aug 31, 2004, at 6:30 PM, Josh Berkus wrote:
>>> Huh? You can replicate onto the same server. Kicks your
>>> performance in
>>> the teeth but it works fine. Heck, I did it on my laptop as a demo.
>>
>> Doesn't work If you have say, a 100GB db and only 50GB free space.
>> Not nearly enough to duplicate. But plenty of breathing room for normal
>> operation.
>>
>> Various db's support in place upgrades. and I'm thankful I tried
>> Informix's out on a test db first because it simply scribbled over all
>> the data instead of upgrading. Support told me that can happen
>> sometimes. COOL HUH?
>
> I think that's an incredibly important point, i.e., even if you want to
> do an "in place" upgrade, you ought to be testing it out first on a
> *full* copy of your production database. IMHO, anything less than a full
> test is playing fast-and-loose with your data. This in turn implies that
> you need enough space for a full replica anyway, so why not use slony?
Which is another point I was about to ask. How do these people, running
those huge and horribly important databases, ever test a single
application change? Or any schema changes for that matter. Do they
really type "psql -c 'alter table ...' proddb" and believe they are
professional users because they know what they are doing?
And don't tell me "we have a backup, so we could ...". That would mean
that you can afford the downtime in the first place.
Jan
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