Improve speed of COPY COMMAND in postgres

Question

I would like to understand if increasing work_mem does help improving the speed of the COPY command.

Does COPY use work_mem or maint_work_mem extensively?

• jmelesky: Are you using COPY for a table, or for the results of a query? If the latter, then optimizing the query will be the way to speed things up.
• Ramya: It's COPY for a table which is 250 GB and I am importing it from S3 to RDS Postgres

Answer 1

No, COPY does not need a lot of memory.

There are two things to speed up COPY:

• Remove any indexes and constraints on the table before you COPY into it.

• Increase max_wal_size so that you don't get more checkpoints than necessary.

  Of course, if you COPY into an UNLOGGED table, it will be even faster.