Thread: ALTER EXTENSION UPGRADE patch v1
Hi, Please find attached the patch to support ALTER EXTENSION UPGRADE, following exchanges made on this list — we can't really speak about decisions here, apparently, until commit is done :) The documentation is available online for easy browsing here: http://pgsql.tapoueh.org/extensions/doc/html/extend-extension.html The things we might want to discuss are, AFAIUI: - support for upgrading from pre-9.1 extension, or to get from a bunch of related pl code to a proper extension in your database I've done the code for that to work, the idea is pretty simple and relies on the following points. Please note that the attached patch only implements support for upgrading some contrib modules from pre-9.1, that's because I'm willing to get some approvement before continuing the effort — I foresee no road blocks here. - CREATE WRAPPER EXTENSION If you want to upgrade an extension, it first has to exists as an extension. When you're wanting to switch to extension, you need a way to bootstrap your extension object, because you want an entry in the catalogs and you don't want to run the script: it has already been run before you decided this would make for an extension. This command allows you to register an extension in the catalogs, bypassing any script and forcing the version to NULL. I'm not sold on the 'WRAPPER' keyword here, I just used an existing one in the grammar that looked like a good candidate. This was the best I could find, but IANANS (I am not a native speaker). - ALTER EXTENSION ... UPGRADE This allows you to upgrade an existing extension, wrapper included. The extension author needs to prepare the upgrade scripts, and to setup in the control file which to use. The new extension's version is static as the upgrade files you distribute depend on this (think packaging here) and so you pick the upgrade script file to execute depending only on the currently installed version. This picking is made by regular expression matching (using the code backing the ~(text, text) operator), and supports null as a special case. The first match wins, other candidates are bypassed. - CREATE EXTENSION ... WITH SYSID ... Thinking about upgrades, I added support for that too. This might be necessary for pg_upgrade, but I'm not so sure. It was an experiment but I though we might as well talk about it before I remove it from the patch :) - ALTER OBJECT ... SET EXTENSION ... This implements the magic behind "upgrading from null", as it allows the users to add objects to an existing extension. Internally, this will only record a INTERNAL depedency between the object and the extension. This is mainly for use in upgrade scripts when you support pre-9.1 extension upgrade, or for internal PL code that grows into an extension after the fact. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
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On Tue, Jan 04, 2011 at 12:31:55PM +0100, Dimitri Fontaine wrote: > Hi, > > Please find attached the patch to support ALTER EXTENSION UPGRADE, Do you plan to have ALTER EXTENSION ... UPGRADE TO VERSION ... , or the more general, ALTER EXTENSION ... ALTER VERSION TO ... ? I get that this might not be a 9.1 feature, but it's sure to be one people who need to deploy software want. A lot. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
David Fetter <david@fetter.org> writes: > Do you plan to have > > ALTER EXTENSION ... UPGRADE TO VERSION ... > > , or the more general, > > ALTER EXTENSION ... ALTER VERSION TO ... ? Well why not, but I'm not sure I understand what you have in mind here. I don't exactly see how to install more than one version on the server, at the filesystem level, with the current infrastructure. The way debian solves it for multi-versions packages, such as PostgreSQL for example, is to add the (major) version number in the package name, so that you have independent packages such as: postgresql-8.3 postgresql-8.4 postgresql-9.0 Are you thinking about doing something similar with extensions? The only other way I'm able to think about your request would be for the command to simply ERROR out when the premises given by the users are not matching the reality of what's installed both in the catalogs and on the file system. If that's what you're talking about, we still can make it material for 9.1, I believe. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
On Tue, Jan 04, 2011 at 08:31:19PM +0100, Dimitri Fontaine wrote: > David Fetter <david@fetter.org> writes: > > Do you plan to have > > > > ALTER EXTENSION ... UPGRADE TO VERSION ... > > > > , or the more general, > > > > ALTER EXTENSION ... ALTER VERSION TO ... ? > > Well why not, but I'm not sure I understand what you have in mind here. One could imagine that an extension was updated more quickly than PostgreSQL major versions come out, or at least not at the exact same time. > I don't exactly see how to install more than one version on the > server, at the filesystem level, with the current infrastructure. It's probably not worth worrying about the multiple version issue for 9.1, but it probably *is* for 9.2. > The way debian solves it for multi-versions packages, such as PostgreSQL > for example, is to add the (major) version number in the package name, > so that you have independent packages such as: > postgresql-8.3 > postgresql-8.4 > postgresql-9.0 > > Are you thinking about doing something similar with extensions? Vaguely. See above. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
David Fetter <david@fetter.org> writes: > One could imagine that an extension was updated more quickly than > PostgreSQL major versions come out, or at least not at the exact same > time. Sure, but I don't see what your proposed syntax is giving us here. Currently the new version you're upgraded to is the one installed on the file system, and whose .so has already been upgraded, and that's it. I still need a better grasp at what your proposal is about to comment and integrate, I fear. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
On Wed, Jan 05, 2011 at 10:19:23AM +0100, Dimitri Fontaine wrote: > David Fetter <david@fetter.org> writes: > > One could imagine that an extension was updated more quickly than > > PostgreSQL major versions come out, or at least not at the exact same > > time. > > Sure, but I don't see what your proposed syntax is giving us here. The syntax by itself does nothing, but the underlying capability gives users: - The ability to have versions of software on different databases on the same system. - The ability to do deterministic upgrades, rather than just, "upgrade me to the latest, which may be buggy and/or slow thingsdown to avoid a problem I know I don't have." > Currently the new version you're upgraded to is the one installed on > the file system, and whose .so has already been upgraded, and that's > it. > > I still need a better grasp at what your proposal is about to > comment and integrate, I fear. I am not saying that this is a show-stopper. I *am* saying that multiple concurrent versions and deterministic upgrades are common enough requests that you shouldn't do things that would prevent those in the future. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
David Fetter <david@fetter.org> writes: > The syntax by itself does nothing, but the underlying capability gives > users: Ok, now I understand that the syntax you proposed was a shortcut for an I-want-it-all request :) > - The ability to have versions of software on different databases on > the same system. > > - The ability to do deterministic upgrades, rather than just, "upgrade > me to the latest, which may be buggy and/or slow things down to > avoid a problem I know I don't have." Both depends on a filesystem organization rework. > I am not saying that this is a show-stopper. I *am* saying that > multiple concurrent versions and deterministic upgrades are common > enough requests that you shouldn't do things that would prevent those > in the future. Would it be useful to have the syntax support in 9.1 already, but which would only check that the asked-of new version (and current version) are the one currently available (and installed), and ERROR out otherwise? I think that syntax-and-check is still doable for 9.1, if there's a will to get there. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support