Closed Bug 248175 (bz-dbinstall) Opened 16 years ago Closed 15 years ago
Installation needs to support DB-independence
Today, checksetup makes mysql assumptions all over the place. For 2.18 and prior, that is a safe assumption. BEFORE anyone lands a DB-compatibility solution, we need to fix this. My suggestion is as follows.... First, move the code that upgrades sites from checksetup to legacychecksetup, deleting the module checks and the administrator setup in the process. The new checksetup should perform operations in the following order... 1) Check requirements 2) Determine current Table configuration (schema only) [If current predates new checksetup, call the old checksetup code] 3) Add new fields/tables to schema (or ask a DBA to do so) 4) Determine migrations to be done [cannot rely on information from step 2, we may be run again after a DBA finishes the schema adds] 5) Do the migrations 6) Determine the schema deletions or renames to be done I am suggesting we make a point of preserving the old upgrade code prior to the first version that does this. The whole approach still does raise some interesting questions. Such as... a) If extra fields or tables are in the DB and not in checksetup, do we automatically remove them or do we keep a list of fields that checksetup has ever wanted to remove. b) Can we always determine what conversion code needs to run solely by looking at the schema? For example, we add a new field that never existed... -->We should be able to just add it to the db-independent table description. add a new field that needs program initialization -->We add it to the db-independent table description. -->init code checks for the field existing AND being uninitialized change a field to a reference to another table -->We add the new stuff to the db-independent table descriptions. -->init code checks for the new field existing AND old field existing AND being uninitialized -->cleanup code checks for the new field existing AND old field existing AND initilization already done --> deletes old field etc...
There's nothing wrong with automatically performing schema updates and data conversions at the same time... however, it all needs to happen from a separate script that can be run by the DBA. In the typical enterprise world, the application user ('bugs') is not going to be granted enough permissions to create, alter, and drop tables. The primary checksetup.pl script, run by the application admin, should be able to tell if changes are necessary, but not actually make them (of course, it can offer to run the upgrade script, so it can all be done at once if needed). The script which actually makes the changes should prompt for a DBA username and password, rather than using one from a data file. The checking can always be done from the same script, and called in such a way that it knows to log in with the normal bugs user and only check instead of update, so we avoid duplication of code. Ideally, to prevent stranding people using a specific database, there should NOT be a separate upgrade/setup script for each database, but instead try to do it in a database agnostic way as much as possible, and use some kind of common schema definition that defines any extra attributes needed for tables/columns to deal with the places where being agnostic isn't possible. (which is what bug 146679 is about I think)
Depends on: bz-dbschema
(In reply to comment #1) > Ideally, to prevent stranding people using a specific database, there should NOT > be a separate upgrade/setup script for each database, but instead try to do it > in a database agnostic way as much as possible, and use some kind of common > schema definition that defines any extra attributes needed for tables/columns to > deal with the places where being agnostic isn't possible. (which is what bug > 146679 is about I think) Certainly. I've always hoped that a future version of checksetup.pl would utilize the Schema modules that I and others have been working on in bug 146679, but I'm hoping someone else will take care of adapting checksetup.pl to utilize the Schema modules. Right now, the Schema object class only has a single public method (besides the constructor) that returns all of the SQL used to create the Bugzilla schema. Can anyone think of any other methods that checksetup.pl might need from the Schema class?
Here's the point... The existing (legacy) checksetup will have to get mysql legacy (the only kind that exists) up to some key point. Starting with that point, whatever does this must carry all the schema forward in an agnostic way. I think we are all saying the same thing. However, it is easy to forget that this needs more than just a way forward alone. The checksetup replacement must know when it has to call the legacy checksetup for upgrading sites.
Bugzilla 2.20 feature set is now frozen as of 15 Sept 2004. Anything flagged enhancement that hasn't already landed is being pushed out. If this bug is otherwise ready to land, we'll handle it on a case-by-case basis, please set the blocking2.20 flag to '?' if you think it qualifies.
Target Milestone: Bugzilla 2.20 → Bugzilla 2.22
I'll take this, because it's one of two major blockers for bug 98304, which is important to me. I think what's really important is that checksetup needs to support DB-independence. It doesn't have to be *replaced* in order to do this, it just has to do it. We have years and years of stable code in checksetup, there's no need to throw it all away just because it's large and complicated. If we'd like to re-write checksetup for some other reason, I think that could be another bug. If anybody disagrees, and would actually like to write this code, they can feel free to take this bug back from me. :-)
Assignee: zach → mkanat
Summary: Checksetup needs to be replaced to support DB-independence → Checksetup needs to support DB-independence
Depends on: bz-enums
Summary: Checksetup needs to support DB-independence → Installation needs to support DB-independence
I'm going to start working on this on what will essentially be a large fork (with the current patches in bug 146679 and bug 277617) and then merge some of my changes back in.
Status: NEW → ASSIGNED
Target Milestone: Bugzilla 2.22 → Bugzilla 2.20
This and all its deps is currently the major 2.20 blocker.
"If it's not a regression from 2.18 and it's not a critical problem with something that's already landed, let's push it off." - Dave
Without this bug landing, no PostgreSQL installation will be able to upgrade to 2.20. So I'd say it blocks 2.20.
OK, this bug is now considered complete now that all blockers have been resolved. From now on, the ability to install on a new DB should depend mostly on just writing a new driver and the associated Schema module.
Status: ASSIGNED → RESOLVED
Closed: 15 years ago
Resolution: --- → FIXED
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