Subject: POSTGRES Append Performance

From: "William T. Smith" <[email-masked]>
Date: Thu, 12 Jan 1995 14:07:47 -0500 (EST)

Hello,

	I am evaluating version 4.2 of POSTGRES as a database tool to
provide persistent storage of directed graphs.  The test program adds
one node which requires 17 append operations against an empty database.
Each instance has less than 100 bytes.  The program takes 10 seconds
elapsed time to execute.  Adding ten nodes takes 20 seconds.  Is this
"normal" performance for POSTGRES?  Does anyone have any suggestions to
improve performance? Is anyone using POSTGRES to support interactive
applications.

	The program is run on a SPARC10 workstation with SunOS 5.3.
The database resides on the workstation.

Thanks.

Ted

-- 
Ted Smith                                           MCNC
Internet: [email-masked]           Information Technologies Division
Voice:    919-248-9232               P.O. Box 12889, 3021 Cornwallis Rd.
Fax:      919-248-9245               Research Triangle Park, NC 27709-2889

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From: [email-masked] (Kai Petzke)
Date: Fri, 13 Jan 1995 01:42:19 +0100 (MET)

> improve performance? Is anyone using POSTGRES to support interactive

Postgres has the overhead of all RDBMS systems: it has to parse the
queries, then optimize then, then do the actual work.  While doing
the first steps, tons of tuples are accessed from the pg_* files
of your database.

If you want better update performance for multiple tuples, use the 
"copy in" function.  Here, the parsing is done only once for the
complete set, not once for every datum.

Kai