On Fri, Jun 17, 2022 at 1:34 AM James Pang (chaolpan) <chaol...@cisco.com> wrote:
> Hi , > > We plan to migrate large database from Oracle to Postgres(version 13.6, > OS Redhat8 Enterprise), we are checking options to make data load in > Postgres fast. Data volume is about several TB, thousands of indexes, > many large table with partitions. We want to make data load running fast > and avoid miss any indexes when reindexing. There are 2 options about > reindex. Could you give some suggestions about the 2 options, which option > is better. > > > > 1. Create tables and indexes( empty database) , update pg_index set > indisready=false and inisvalid=false, then load data use COPY from csv , > then reindex table … > > Where did this idea come from? This is likely to destroy your database. > 2). Use pg_dump to dump meta data only , then copy “CREATE INDEX … sql “ > > Drop indexes before data load > > After data load, increase max_parallel_maintenance_workers, > maintenance_work_mem > > Run CREATE INDEX … sql to leverage parallel create index feature. > pg_dump doesn't run against Oracle, so where is the thing you are running pg_dump against coming from? If you already have a fleshed out schema in PostgreSQL, you should dump the sections separately (with --section=pre-data and --section=post-data) to get the commands to build the objects which should be run before and after the data is loaded. Cheers, Jeff >
