performance of loading CSV data with COPY is 50 times faster than Perl::DBI

Hello,

Since ages, we transfer data between different DBS (Informix, Sybase,
Oracle, and now PostgreSQL) with our own written tool, based on
Perl::DBI which produces a CSV like export in a common way, i.e. an
export of Oracle can be loaded into Sybase and vice versa. Export and
Import is done row by row, for some tables millions of rows.

We produced a special version of the tool to export the rows into a
format which understands the PostgreSQL's COPY command and got to know
that the import into PostgreSQL of the same data with COPY is 50 times
faster than with Perl::DBI, 2.5 minutes ./. 140 minutes for around 6
million rows into an empty table without indexes.

How can COPY do this so fast?

matthias

--
Matthias Apitz, ✉ guru(at)unixarea(dot)de, http://www.unixarea.de/ +49-176-38902045
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