Re: [sqlalchemy] The use of SQLAlchemy for a long term project

2015-04-20 Thread Van Klaveren, Brian N.
Thanks for the detailed response. I didn't think to look to Red Hat's to see if 
they backported security fixes, so that's good to know.

As for the undefined behavior with respect to less-than idiomatic programming, 
I think that's something we'll definitely need to keep in mind and hopefully be 
able to enforce with code reviews.

I've personally been wanting to use SQLAlchemy, but it's important we 
understand implications for decisions like this when the lifetime of code is 
guaranteed to surpass a decade. I'm pretty sure we'll end up using SQLAlchemy 
for the long term.

Thanks again,
Brian


On Apr 18, 2015, at 2:47 PM, Mike Bayer 
mike...@zzzcomputing.commailto:mike...@zzzcomputing.com wrote:



On 4/17/15 6:58 PM, Van Klaveren, Brian N. wrote:
Hi,

I'm investigating the use and dependency on SQLAlchemy for a long-term 
astronomy project. Given Version 1.0 just came out, I've got a few questions 
about it.

1. It seems SQLAlchemy generally EOLs versions after about two releases/years. 
Is this an official policy? Is this to continue with version 1.0 as well? Or is 
it possible 1.0 might be a something of a long-term release.
2. While well documented and typically minimal, SQLAlchemy does have occasional 
API and behavioral changes to be aware of between versions. Is the 1.0 API more 
likely to be stable on the time frame of ~4 years?

Put another way, would you expect that it should be easier to migrate from 
version 1.0 to the 1.4 (or whatever the current version is) of SQLAlchemy in 
five years than it would be to migrate from 0.6 to 1.0 today.

I know these questions are often hard to answer with any certainty, but these 
sorts of projects typically outlive the software they are built on and are 
often underfunded as far as software maintenance goes, so we try to plan 
accordingly.

(Of course, some people just give up and through everything in VMs behind 
firewalls)
Well the vast majority of bugs that are fixed, like 99% of them, impact only 
new development, that is, they only have a positive impact someone who is 
writing new code, using new features of their database backend, or otherwise 
attempting to do something new; they typically only serve to raise risk and 
decrease stability of code that is not under active development and is 
stabilized on older versions of software.

These kinds of issues mean that some way of structuring tables, mapped classes, 
core SQL or DDL objects, ORM queries, or calls to a Session produce some 
unexpected result, but virtually always, this unexpected result is consistent 
and predictable.   An application that is sitting on 0.5 or 0.6 and is running 
perfectly fine, because it hasn't hit any of these issues, or quite often 
because it has and is working around them (or even relying upon their behavior) 
would not benefit at all from these kinds of fixes being backported, but would 
instead have a greater chance of hitting a regression or a change in 
assumptions if lots of bugfixes were being backported from two or three major 
versions forward.

So it's not like we don't backport issues three or four years back because it's 
too much trouble, it's because these backports wouldn't benefit anyone and they 
would only serve to wreak havoc with old and less maintained applications when 
some small new feature or improvement in behavioral consistency breaks some 
assumption made by that application.

As far as issues that are more appropriate for backporting, which would be 
security fixes and stability enhancements, we almost never have issues like 
that; the issues we have regarding stability, like memory leaks and race 
conditions, again typically occur in conjunction with a user application doing 
something strange and unexpected (e.g. new development), and as far as security 
issues the only issue we ever had like that even resembled a security issue was 
issue 2116 involving limit/offset integers not being escaped, which was 
backported from 0.7 to 0.6.  Users who actually needed enterprise-level 
longevity who happened to be using for example the Red Hat package could see 
the backport for this issue backported all the way to their 0.5 and 0.3 
packages.  But presence of security/memory leak/stability issues in modern 
versions is extremely rare, and we generally only see new issues involving 
memory or stability as a result of new features (e.g. regressions).

There's also the class of issues that involve performance enhancements.   Some 
of these features would arguably be appropriate to backport more than several 
major versions, but again they are often the result of significant internal 
refactorings and definitely would raise risk for an older application not 
undergoing active development.   An older application that wants to take 
advantage of newer performance features would be better off going through the 
upgrade process than risking running on top of a library that is a hybrid of 
very old code and backported newer approaches, which will see 

Re: [sqlalchemy] The use of SQLAlchemy for a long term project

2015-04-18 Thread Mike Bayer



On 4/17/15 6:58 PM, Van Klaveren, Brian N. wrote:

Hi,

I'm investigating the use and dependency on SQLAlchemy for a long-term 
astronomy project. Given Version 1.0 just came out, I've got a few questions 
about it.

1. It seems SQLAlchemy generally EOLs versions after about two releases/years. 
Is this an official policy? Is this to continue with version 1.0 as well? Or is 
it possible 1.0 might be a something of a long-term release.
2. While well documented and typically minimal, SQLAlchemy does have occasional 
API and behavioral changes to be aware of between versions. Is the 1.0 API more 
likely to be stable on the time frame of ~4 years?

Put another way, would you expect that it should be easier to migrate from 
version 1.0 to the 1.4 (or whatever the current version is) of SQLAlchemy in 
five years than it would be to migrate from 0.6 to 1.0 today.

I know these questions are often hard to answer with any certainty, but these 
sorts of projects typically outlive the software they are built on and are 
often underfunded as far as software maintenance goes, so we try to plan 
accordingly.

(Of course, some people just give up and through everything in VMs behind 
firewalls)
Well the vast majority of bugs that are fixed, like 99% of them, impact 
only new development, that is, they only have a positive impact someone 
who is writing new code, using new features of their database backend, 
or otherwise attempting to do something new; they typically only serve 
to raise risk and decrease stability of code that is not under active 
development and is stabilized on older versions of software.


These kinds of issues mean that some way of structuring tables, mapped 
classes, core SQL or DDL objects, ORM queries, or calls to a Session 
produce some unexpected result, but virtually always, this unexpected 
result is consistent and predictable.   An application that is sitting 
on 0.5 or 0.6 and is running perfectly fine, because it hasn't hit any 
of these issues, or quite often because it has and is working around 
them (or even relying upon their behavior) would not benefit at all from 
these kinds of fixes being backported, but would instead have a greater 
chance of hitting a regression or a change in assumptions if lots of 
bugfixes were being backported from two or three major versions forward.


So it's not like we don't backport issues three or four years back 
because it's too much trouble, it's because these backports wouldn't 
benefit anyone and they would only serve to wreak havoc with old and 
less maintained applications when some small new feature or improvement 
in behavioral consistency breaks some assumption made by that application.


As far as issues that are more appropriate for backporting, which would 
be security fixes and stability enhancements, we almost never have 
issues like that; the issues we have regarding stability, like memory 
leaks and race conditions, again typically occur in conjunction with a 
user application doing something strange and unexpected (e.g. new 
development), and as far as security issues the only issue we ever had 
like that even resembled a security issue was issue 2116 involving 
limit/offset integers not being escaped, which was backported from 0.7 
to 0.6.  Users who actually needed enterprise-level longevity who 
happened to be using for example the Red Hat package could see the 
backport for this issue backported all the way to their 0.5 and 0.3 
packages.  But presence of security/memory leak/stability issues in 
modern versions is extremely rare, and we generally only see new issues 
involving memory or stability as a result of new features (e.g. 
regressions).


There's also the class of issues that involve performance 
enhancements.   Some of these features would arguably be appropriate to 
backport more than several major versions, but again they are often the 
result of significant internal refactorings and definitely would raise 
risk for an older application not undergoing active development.   An 
older application that wants to take advantage of newer performance 
features would be better off going through the upgrade process than 
risking running on top of a library that is a hybrid of very old code 
and backported newer approaches, which will see a lot less real-world 
testing.


So short answer, the EOL you see of those old versions is generally a 
good thing as those old versions are running in old applications that 
aren't seeing lots of new development and would see a mostly negative 
effect and little to no benefit from the code continuing to change.   
SQLAlchemy is a development library so generally an application that's 
been put into production against a certain version has been well tested 
and tuned against the behaviors of that specific version.


As far as API and behavioral changes, as far as API we are really 
conservative about actually changing APIs such that an older approach 
won't work anymore.   That happened a 

[sqlalchemy] The use of SQLAlchemy for a long term project

2015-04-17 Thread Van Klaveren, Brian N.
Hi,

I'm investigating the use and dependency on SQLAlchemy for a long-term 
astronomy project. Given Version 1.0 just came out, I've got a few questions 
about it.

1. It seems SQLAlchemy generally EOLs versions after about two releases/years. 
Is this an official policy? Is this to continue with version 1.0 as well? Or is 
it possible 1.0 might be a something of a long-term release.
2. While well documented and typically minimal, SQLAlchemy does have occasional 
API and behavioral changes to be aware of between versions. Is the 1.0 API more 
likely to be stable on the time frame of ~4 years?

Put another way, would you expect that it should be easier to migrate from 
version 1.0 to the 1.4 (or whatever the current version is) of SQLAlchemy in 
five years than it would be to migrate from 0.6 to 1.0 today.

I know these questions are often hard to answer with any certainty, but these 
sorts of projects typically outlive the software they are built on and are 
often underfunded as far as software maintenance goes, so we try to plan 
accordingly. 

(Of course, some people just give up and through everything in VMs behind 
firewalls)

Brian


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