Re: Re: Migrating from MS SQL 7 - Mailing list pgsql-general

Shouldn't we have a "Migrating to PostgreSQL" section in the FAQ here:
http://www.postgresql.org/docs/faq-english.html ?

I remember learning this the hard way - from MS Access to PostgreSQL :(

Poul L. Christiansen

Alexander Jerusalem wrote:
>
> Hi Peter,
>
> I have done the same and for similar reasons. In general it worked fine.
> The biggest problem with migration from SQL Server to almost any other
> database is always that SQL Server uses case insensitive string comparisons
> by default whereas other DBMSs use case sensitive comparisons and collation
> order. Postgresql has two features that make your life easier in that
> respect: You can use function based indexes with lower() and/or you can use
> ILIKE instead of LIKE for case insensitive wildcard searches. There's some
> other magic postgres can do with regular expressions but I don't know that
> feature very well.
>
> The other thing I trapped into only recently is that correlated subqueries
> using IN don't use indexes in postgres and are therefore very slow. You can
> work around that by using EXISTS instead. There's a note on this in the FAQ.
>
> I'm also working with Oracle and my experience was that it's much harder
> (and much more expensive) to migrate to Oracle because function based
> indexes are only available in Oracle enterprise edition which truely costs
> a fortune. And something like ILIKE doesn't exist in Oracle at all. I use
> Oracle only in projects where a single database server is not enough for
> scalability or high availability reasons so I need to use Oracle Parallel
> Server.
>
> When it comes to maintainance, you have to be aware, that you must run
> vacuumdb on your postgresql database from time to time to keep good query
> performance (especially if you have much update and delete activity). If
> you do that, postgresql performance is comparable to SQL Server (I've not
> done extensive performance testing though).
>
> I have "shopped" around a lot for databases on Linux and tried some things.
> Postgresql is by far the most powerful DBMS of those I have looked at. The
> community is very helpful and the developers are doing a good job in
> bringing up new features and fixing bugs. Above all Postgres runs very
> stable, I never had mysterious standstills (like those I frequently
> experienced with SQL Server 6.x)
>
> Regards,
>
> Alexander Jerusalem
>
> At 16:56 18.03.01, Peter Morgan wrote:
> >Anyone migrated from SQL server 7 to PostgreSQL
> >
> >I'm considering this so I can replace my NT box with Linux for deployment
> >across a business.
> >
> >Any advice would be appreciated
> >
> >Pete
> >
> >
> >
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