Message-ID: <41b4852ea43e59969cfefaf37c4578a23000075b.camel@cybertec.at>
Subject: Re: Difference between Bulk Load (Multiple inserts or single
 inserts) and COPY
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: mayank.l.patel90@gmail.com, pgsql-docs@lists.postgresql.org
Date: Tue, 19 Nov 2019 23:55:44 +0100
In-Reply-To: <157418972366.28426.16885409770050714771@wrigleys.postgresql.org>
References: 
	<157418972366.28426.16885409770050714771@wrigleys.postgresql.org>
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Precedence: bulk

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
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