Обсуждение: Tips for upgrading from 7.4

I'm working with someone who is about to upgrade from (I believe) pg 7.4
to pg 8.1.

What would be the best resource to read to look for "gotchas"?  Release
notes?  At the moment, we don't care about performance problems, only
things that might break.

Rick Schumeyer <rschumeyer@ieee.org> writes:
> I'm working with someone who is about to upgrade from (I believe) pg 7.4
> to pg 8.1.

> What would be the best resource to read to look for "gotchas"?  Release
> notes?  At the moment, we don't care about performance problems, only
> things that might break.

Reading the release notes is good, but you really really should test the
application(s) against a test 8.1 installation before you go live ...

            regards, tom lane

Tom Lane wrote:
> Rick Schumeyer <rschumeyer@ieee.org> writes:
>
>> I'm working with someone who is about to upgrade from (I believe) pg 7.4
>> to pg 8.1.
>>
>
>
>> What would be the best resource to read to look for "gotchas"?  Release
>> notes?  At the moment, we don't care about performance problems, only
>> things that might break.
>>
>
> Reading the release notes is good, but you really really should test the
> application(s) against a test 8.1 installation before you go live ...
>
>             regards, tom lane
>
We plan on testing.  I'm asking if there is anything that "everyone
knows" will break that we might as well fix before testing.

On Jan 23, 2008, at 10:26 AM, Tom Lane wrote:

> Reading the release notes is good, but you really really should test
> the
> application(s) against a test 8.1 installation before you go live ...

be sure to run *every* query your system uses through 8.1.  the most
common problems you will run into are issues relating to using strings
as integers which tended to work in most cases in 7.x but not in 8.x.

the release notes cover such changes.  pay particular attention to
changes in auto typecasts.

Vivek Khera <vivek@khera.org> writes:
> On Jan 23, 2008, at 10:26 AM, Tom Lane wrote:
>> Reading the release notes is good, but you really really should test
>> the
>> application(s) against a test 8.1 installation before you go live ...

> be sure to run *every* query your system uses through 8.1.  the most
> common problems you will run into are issues relating to using strings
> as integers which tended to work in most cases in 7.x but not in 8.x.

BTW, one other question to answer at this point, rather than down the
road, is "why 8.1"?  If you're going to have to engage in a testing
and porting effort anyway, you might as well move to the latest branch
you can.  I'd strongly recommend moving to 8.2 instead of 8.1, or
maybe even 8.3 if your go-live date is more than a month or two away.

            regards, tom lane

Rick Schumeyer wrote:
> Tom Lane wrote:
>> Rick Schumeyer <rschumeyer@ieee.org> writes:
>>
>>> I'm working with someone who is about to upgrade from (I believe) pg
>>> 7.4 to pg 8.1.
>>>
>>
>>
>>> What would be the best resource to read to look for "gotchas"?
>>> Release notes?  At the moment, we don't care about performance
>>> problems, only things that might break.
>>>
>>
>> Reading the release notes is good, but you really really should test the
>> application(s) against a test 8.1 installation before you go live ...
>>
>>             regards, tom lane
>>
> We plan on testing.  I'm asking if there is anything that "everyone
> knows" will break that we might as well fix before testing.
Only to the extent that "everyone knows" the details of your PG
configuration and all connecting applications. Print the release-notes
chain and start reading/scribbling on it. Then expect to discover that
you don't know your apps as well as you thought.

We have encountered relatively few difficulties - most of ours revolved
around subtle changes to both automatic and explicit casting.

For example given and input of '<space>0<space>' you might see a change
from:

select ' 0 '::int;
ERROR:  invalid input syntax for integer: " 0 "

to this:

select ' 0 '::int;
 int4
------
    0

If you are already scrupulous about formatting and casting, you are
probably OK. If you relied on "getting away with" certain loose
behavior, you might find bugs.

BTW, why not upgrade to the latest version?

Cheers,
Steve

Steve Crawford wrote:
>
>
> BTW, why not upgrade to the latest version?
>
> Cheers,
> Steve
>

Mostly because its not my server :-)  I've suggested that, we'll see.

I appreciate the comments regarding type casting.  I'll be sure to look
out for that.