Re: Difference between Bulk Load (Multiple inserts or single inserts) and COPY

On Tue, 2019-11-19 at 18:55 +0000, PG Doc comments form wrote:
> I experimented with Bulk load and COPY.
> Loading in COPY was very fast.
> However, after COPYing data from a CSV file to PostgreSQL Table. The query
> execution took lot of time for 1 of the first 4 queries.
> Only this slow query was taking so much time, that even if I had used normal
> bulk load, it would have been faster in total.
> Then all other Query executions took equal time as it took while querying a
> table after the Bulk data load method.
>
> So, I want to know the exact reason what's the issue with COPY.
> How exactly they differ? The only thing from the document I could identify
> was row security.
> But it did not mention anything about indexing. Like, in Bulk load, do
> indices(or constraint checks) are created with data loading?
> & in COPY it's done after? so when indices are being created that query
> slows down??
>
> Please reply soon with more details or send a link where I can read it in
> depth.

That cannot be answered without knowing the exact statements and the
table definitions.

Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com