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
