Re: Help with bulk read performance - Mailing list pgsql-performance

From Pierre C
Subject Re: Help with bulk read performance
Date
Msg-id op.vntbn2ujeorkce@apollo13
Whole thread Raw
In response to Re: Help with bulk read performance  (Dan Schaffer <Daniel.S.Schaffer@noaa.gov>)
Responses Re: Help with bulk read performance
List pgsql-performance
> If the data are stored as a byte array but retrieve into a ResultSet,
> the unpacking time goes up by an order of magnitude and the
> observed total throughput is 25 MB/s.  If the data are stored in a
> Postgres float array and unpacked into a byte stream, the
> observed throughput is 20 MB/s.


float <-> text conversions are very slow, this is in fact due to the
mismatch between base-2 (IEEE754) and base-10 (text) floating point
representation, which needs very very complex calculations.

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