Re: Synchronizing the schema of two PostgreSQL databases

Hello Jason,

Hm.

From the sound of your question, you may want to investigate changing
the logging levels for your installation of PostgreSQL.

PostgreSQL can log queries that come into the server, in varying amounts.

Carefully adjusting the settings listed here in the documentation should
let you find the correct level for your particular situation.

http://www.postgresql.org/docs/8.3/interactive/runtime-config-logging.html

From there, it should just be a matter of parsing the log and
extracting the desired queries. =)

Hopefully this puts you on the right track.

Good luck! =)

Lacey
> Thank you for the insight Lacey. Now I have another question. If
> anyone is familiar with Apple's Final Cut Server program, you may know
> that it uses PostgreSQL for its backend database. My question then
> becomes "If one were to be using this Final Cut Server program, would
> there be any way to listen in on the SQL happenings so that I could
> capture any changes made to the schema of the database?" (and then
> later paste them into a begin/commit block) And again, I realize that
> these are obscure questions, but I've got to take a shot at it...
> Thanks again in advance.
>
>
> Jason Stelzel
> postgreslist(at)epigraf(dot)com <mailto:postgreslist(at)epigraf(dot)com>
>
>
> ----- Original Message -----
> *From:* Lacey Powers <mailto:lacey(dot)powers(at)commandprompt(dot)com>
> *To:* Jason Stelzel <mailto:postgreslist(at)epigraf(dot)com>
> *Cc:* pgsql-novice(at)postgresql(dot)org
> <mailto:pgsql-novice(at)postgresql(dot)org>
> *Sent:* Tuesday, July 28, 2009 3:28 PM
> *Subject:* Re: [NOVICE] Synchronizing the schema of two PostgreSQL
> databases
>
> Hello Jason,
>
> Welcome to the list. =)
>
> Keeping schemas synchronized is a difficult task.
>
> You will definitely want a process for this, and a version control
> system like SVN or Mercurial to help keep track of the files and
> changes, since this could get quite complicated quite quickly.
>
> I'd recommend two people at most, with a process that has to be
> followed and apply the changes as patch sets, rather than dump the
> whole schema every time.
>
> BEGIN;
> ALTER TABLE foo ALTER COLUMN bar <type>;
> COMMIT;
>
> With a designated primary and secondary database.
>
> I'm sure you get the idea. =)
>
>
> Additionally, you may find a tool that you like in here:
>
> http://wiki.postgresql.org/wiki/Community_Guide_to_PostgreSQL_GUI_Tools
>
>
>
> As for your other questions, there is a concept of a database not
> having a password, but it has some serious caveats associated with it.
>
> You can read more about it here.
>
> http://www.postgresql.org/docs/8.3/interactive/auth-pg-hba-conf.html
>
> http://www.postgresql.org/docs/8.3/interactive/auth-methods.html#AUTH-TRUST
>
> If you don't want to continually enter a password, it is better to
> use the .pgpass or pgpass.conf
>
> http://www.pgadmin.org/docs/1.4/pg/libpq-pgpass.html
>
>
>
> I hope this helps. =)
>
> Lacey
>
>> Hello, (my first post to this list)
>>
>> I'm trying to figure out if there is any easy way to keep the
>> schema of two totally separate databases synchronized. And by
>> that, I mean that if a column is added to one database, is there
>> an easy way to automagically have the other database also include
>> that added column (and vice versa)? I was thinking of something
>> along the lines of capturing the confirmation commands that
>> postgres spits out when a change is made to the database and
>> somehow "playing those commands back" to the other database.
>> Another approach might be to "backup" a schema-only
>> representation of a table and then "restore" it to the other
>> database. I realize that this may be a strange application of
>> pgsql (I can hear people asking right now "Why don't you just use
>> a single database and separate the uses logically?") but this is
>> the requirement I've been tasked with and I understand the
>> application needs as being valid. Thanks in advance for any
>> guidance anyone can provide.
>>
>> Also, is there a concept of a postgres database not having a
>> password? I was using a system which did not require a password
>> (meaning the password field was empty when connecting to it) and
>> the application that accesses it did a conversion of the database
>> to a newer version and now I am locked out of it (using pgAdmin III).
>>
>>
>> Jason Stelzel
>> postgreslist(at)epigraf(dot)com <mailto:postgreslist(at)epigraf(dot)com>
>>
>>
>> __________ Information from ESET NOD32 Antivirus, version of
>> virus signature database 4286 (20090728) __________
>>
>> The message was checked by ESET NOD32 Antivirus.
>>
>> http://www.eset.com
>
>
> --
> Lacey Powers
>
> The PostgreSQL Company - Command Prompt, Inc. 1.503.667.4564 ext 104
> PostgreSQL Replication, Consulting, Custom Development, 24x7 support
>
>
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus
> signature database 4286 (20090728) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>

--
Lacey Powers

The PostgreSQL Company - Command Prompt, Inc. 1.503.667.4564 ext 104
PostgreSQL Replication, Consulting, Custom Development, 24x7 support