Обсуждение: ms-sql -> pg 8.x

Sydney Puente wrote:
> Hello,
> It seems that very shortly I will have to extract some data from
> ms-sql server and load it into postgres.
> It seems that the ms-sql is getting bigger with increasingly more
> users and performance is getting worse n worse.
> And a local copy of data is required for and application that needs
> pull lots of small bits of data back quickly complex queries tho,
> currently embedded in views. And if the data is no older than 24 hours
> that is OK.
>
> Although I am pretty useful with sql on Oracle and mysql this is a bit
> outside my comfort zone.
> Could someone provide a few pointers on how to go about this and what
> the issues might be?

MS SQL Server has a pretty useful Data Translation Engine aka DTE, which
can be used to export data on a scheduled and scripted batch basis to
external databases... You'd need to establish a postgres client with
OLEDB/ADODB or ODBC support on the SQL Server to do it this way.

Alternately, you'd run a script on the SQL Server (or any client that
has access to it) and export the data you want to CSV file(s), then
import these into a postgres database.

Where things might get messy....  if this data is large and growing as
you say, doing a full copy like this could be very time consuming on a
daily basis.    Doing incremental replication between dissimilar
databases is not at all easy.


> The first isssue that occurs to me is that CP1252 is used throughout
> the data and there is a lot of european special characters, e acute
> for example. But the column names etc are regular chars [a-zA-Z].
>

CP1252 aka Windows-1252 is actually pretty close to ISO-8859-1 aka
LATIN1.   The differences are mostly that CP1252 uses the 80-9F section
for additional characters, this is unused in LATIN1.

Personally, I'd probably make the Postgres database UTF-8, then use
Windows-1252 as the client_encoding during the import process.

John R Pierce <pierce@hogranch.com> writes:
> Sydney Puente wrote:
>> The first isssue that occurs to me is that CP1252 is used throughout
>> the data and there is a lot of european special characters, e acute
>> for example. But the column names etc are regular chars [a-zA-Z].

> CP1252 aka Windows-1252 is actually pretty close to ISO-8859-1 aka
> LATIN1.   The differences are mostly that CP1252 uses the 80-9F section
> for additional characters, this is unused in LATIN1.

> Personally, I'd probably make the Postgres database UTF-8, then use
> Windows-1252 as the client_encoding during the import process.

FWIW, we do support win1252 as a database encoding.  I tend to agree
that switching to something better-standardized would be a good idea
though.

            regards, tom lane