Hi,
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Thanks in advance
On 04/28/2016 08:45 AM, Sergio Belkin wrote:
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Back in the Dark Ages of the PostgreSQL RPMset (PostgreSQL 6.5), early in my time as RPM maintainer for the community PostgreSQL.org RPMset, I asked a very similar question of some folks, and I got a canonical answer from Mr. RPM himself, Jeff Johnson.
The answer is not very complex, but it was spread across a several message private e-mail thread. The gist of it is that the RPM scriptlets are very very limited in what they can do. Trying to do something clever inside an RPM scriptlet is almost never wise. The key thing to remember is that the scriptlet has to be able to be run during the OS install phase (back when upgrades were actually supported by the OS installer that is now known as anaconda). Quoting this introductory section:
On August 18, 1999, Jeff Johnson wrote:
The Red Hat install environment is a chroot. That means no daemons, no network, no devices, nothing. Even sniffing /proc can be problematic in certain cases.
Now, I realize that that is OLD information; however, anaconda is still doing the same basic chrooted install, just with a prettier face. You cannot start a daemon in the chroot, since many things are simply not available to the scriptlets when installed/upgraded by anaconda. Scriptlets have to work in an environment other than 'yum update.' And also note that this is a very different situation than Debian packages live in; RPM scriptlets are essentially forbidden from interactivity with the user; Debian's equivalent are not so hindered. At least that was the rule as long as I was an active packager.
Further reference a WayBack Machine archive of a page I wrote long ago: https://web.archive.org/web/20010122090200/http://www.ramifordistat.net/post...
And leaving you with this thought, again from Jeff Johnson:
On August 18, 1999, Jeff Johnson wrote:
Good. Now you're starting to think like a packager Avoiding MUD is *much* more important than attempting magic.
....
The bottom line is you shouldn't attempt a database conversion as part of the package install. The package, however, should contain
programs
and procedures necessary to do the job.
Lamar Owen wrote:
On 04/28/2016 08:45 AM, Sergio Belkin wrote:
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Back in the Dark Ages of the PostgreSQL RPMset (PostgreSQL 6.5), early in my time as RPM maintainer for the community PostgreSQL.org RPMset, I asked a very similar question of some folks, and I got a canonical answer from Mr. RPM himself, Jeff Johnson.
The answer is not very complex, but it was spread across a several message private e-mail thread. The gist of it is that the RPM scriptlets are very very limited in what they can do. Trying to do something clever inside an RPM scriptlet is almost never wise. The key thing to remember is that the scriptlet has to be able to be run during the OS install phase (back when upgrades were actually supported by the OS installer that is now known as anaconda). Quoting this introductory section:
<MVNCH>
We have an answer we really like: yum-post-transaction-actions. Great plugin... and it will do whatever you want... like, say: sed -i s/sbin/shutdown/bin/false/ /etc/apcupsd/apccontrol
mark "and are there three, or six, servers plugged ino the rackmount UPS? Yes."
On 28.04.2016 17:58, Lamar Owen wrote:
On 04/28/2016 08:45 AM, Sergio Belkin wrote:
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Back in the Dark Ages of the PostgreSQL RPMset (PostgreSQL 6.5), early in my time as RPM maintainer for the community PostgreSQL.org RPMset, I asked a very similar question of some folks, and I got a canonical answer from Mr. RPM himself, Jeff Johnson.
The answer is not very complex, but it was spread across a several message private e-mail thread. The gist of it is that the RPM scriptlets are very very limited in what they can do. Trying to do something clever inside an RPM scriptlet is almost never wise. The key thing to remember is that the scriptlet has to be able to be run during the OS install phase (back when upgrades were actually supported by the OS installer that is now known as anaconda). Quoting this introductory section:
On August 18, 1999, Jeff Johnson wrote:
The Red Hat install environment is a chroot. That means no daemons, no network, no devices, nothing. Even sniffing /proc can be problematic in certain cases.
Now, I realize that that is OLD information; however, anaconda is still doing the same basic chrooted install, just with a prettier face. You cannot start a daemon in the chroot, since many things are simply not available to the scriptlets when installed/upgraded by anaconda. Scriptlets have to work in an environment other than 'yum update.' And also note that this is a very different situation than Debian packages live in; RPM scriptlets are essentially forbidden from interactivity with the user; Debian's equivalent are not so hindered. At least that was the rule as long as I was an active packager.
Further reference a WayBack Machine archive of a page I wrote long ago: https://web.archive.org/web/20010122090200/http://www.ramifordistat.net/post...
And leaving you with this thought, again from Jeff Johnson:
On August 18, 1999, Jeff Johnson wrote:
Good. Now you're starting to think like a packager Avoiding MUD is *much* more important than attempting magic.
....
The bottom line is you shouldn't attempt a database conversion as part of the package install. The package, however, should contain
programs
and procedures necessary to do the job.
The real reason something like mysql_upgrade isn't run automatically hasn't really much to do with the technicalities of RPM but the fact that mysql_upgrade might kill your server if you don't know what you are doing. If for example you have a big table that takes up 70% of your storage and mysql_upgrade needs to convert it to a new format then it will create a copy of that table in the new format first and then delete the old one...except of course that this would require 140% of disk space to work.
So independent of the packaging technology used major changes like these should never be done automatically and instead always be handled by an admin who knows what he is doing.
Regards, Dennis
Thanks folks,
Really convincing answers!
2016-04-28 13:53 GMT-03:00 Dennis Jacobfeuerborn dennisml@conversis.de:
On 28.04.2016 17:58, Lamar Owen wrote:
On 04/28/2016 08:45 AM, Sergio Belkin wrote:
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Back in the Dark Ages of the PostgreSQL RPMset (PostgreSQL 6.5), early in my time as RPM maintainer for the community PostgreSQL.org RPMset, I asked a very similar question of some folks, and I got a canonical answer from Mr. RPM himself, Jeff Johnson.
The answer is not very complex, but it was spread across a several message private e-mail thread. The gist of it is that the RPM scriptlets are very very limited in what they can do. Trying to do something clever inside an RPM scriptlet is almost never wise. The key thing to remember is that the scriptlet has to be able to be run during the OS install phase (back when upgrades were actually supported by the OS installer that is now known as anaconda). Quoting this introductory section:
On August 18, 1999, Jeff Johnson wrote:
The Red Hat install environment is a chroot. That means no daemons, no network, no devices, nothing. Even sniffing /proc can be problematic in certain cases.
Now, I realize that that is OLD information; however, anaconda is still doing the same basic chrooted install, just with a prettier face. You cannot start a daemon in the chroot, since many things are simply not available to the scriptlets when installed/upgraded by anaconda. Scriptlets have to work in an environment other than 'yum update.' And also note that this is a very different situation than Debian packages live in; RPM scriptlets are essentially forbidden from interactivity with the user; Debian's equivalent are not so hindered. At least that was the rule as long as I was an active packager.
Further reference a WayBack Machine archive of a page I wrote long ago:
https://web.archive.org/web/20010122090200/http://www.ramifordistat.net/post...
And leaving you with this thought, again from Jeff Johnson:
On August 18, 1999, Jeff Johnson wrote:
Good. Now you're starting to think like a packager Avoiding MUD is *much* more important than attempting magic.
....
The bottom line is you shouldn't attempt a database conversion as part of the package install. The package, however, should contain
programs
and procedures necessary to do the job.
The real reason something like mysql_upgrade isn't run automatically hasn't really much to do with the technicalities of RPM but the fact that mysql_upgrade might kill your server if you don't know what you are doing. If for example you have a big table that takes up 70% of your storage and mysql_upgrade needs to convert it to a new format then it will create a copy of that table in the new format first and then delete the old one...except of course that this would require 140% of disk space to work.
So independent of the packaging technology used major changes like these should never be done automatically and instead always be handled by an admin who knows what he is doing.
Regards, Dennis
CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
On Apr 28, 2016 7:46 AM, "Sergio Belkin" sebelk@gmail.com wrote:
Hi,
I've found some issues upgrading mysql, some people recommends run mysql_upgrade. I wonder why such a script is not run from scriptlet of mysql-server rpm.
Thanks in advance
--
Sergio Belkin LPIC-2 Certified - http:// http://www.lpi.orgwww.l http://www.lpi.org
pi.o http://www.lpi.orgrg http://www.lpi.org
The general SOP is to restart mysql, then run mysql_upgrade, so the RPM script would need to do both. This brings you into database and application management territory, and out of package management territory. The RPM cannot know if it is acceptable and safe for the database to go down, for both your environment and organization. Accordingly, as a rule, RPMs should not affect running services.
Ubuntu/Debian packages *do* perform these actions on package update, and I've seen it go horribly wrong. Like, the restart command hangs because of long running queries, and the tablespace changes happen anyway, leaving the daemon in a state where it cannot accept new connections because it was shutting down, but cannot cleanly shut down because of the other actions in the script. You really want an admin to do this work, not an unattended script.
--Pete
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Dennis Jacobfeuerborn -
Lamar Owen -
m.roth＠5-cent.us -
Pete Travis -
Sergio Belkin