Re: Any optimizations using oracle_fdw with oracle tables that have clob columns?

Thanks for the explanation. We will make the best of what we have given the constraints.

Regards,

Craig
On Jun 19, 2020, 1:00 AM -0600, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>, wrote:
> On Thu, 2020-06-18 at 09:54 -0600, Hotmail wrote:
> > We are moving a table (with almost a billion rows) to Postgres from Oracle using oracle_fdw.
> > We have discovered that there is a single row fetch limitation in oracle when pulling a row
> > that contains a clob column into Postgres.
> >
> > My question is, other than running multiple oracle_fdw parallel threads to speed up the data
> > load are there any other optimizations that we may be unaware for oracle_fdw when working
> > with Oracle clob columns?
>
> No, this is a limitation of Oracle:
>
> https://docs.oracle.com/en/database/oracle/oracle-database/19/lnoci/using-sql_statements-in-oci.html#GUID-7AE9DBE2-5316-4802-99D1-969B72823F02
> "Prefetching is not in effect if LONG, LOB or Opaque Type columns (such as XMLType) are part of the query."
>
> I could change the code to *not* use automatic prefetching and rather explicitly fetch
> rows in bundles, but so far I have been too lazy to complicate the code with that.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>