From: Postgres mailing lists <postgres@weblynk.com>
To: pgsql-interfaces@postgreSQL.org
Subject: JDBC Query performance
Date: Thu, 18 Mar 1999 00:53:36 -0800
Message-ID: <003101be711c$d09ff740$64ba01cc@earthlink.net> (raw)
Hello,
I've been using the JDBC driver that came with postgres 6.4.2. It seems
to work pretty well, but noticed that the query performance seemed very low.
For example, I have a table with about 1200 rows, 20 columns. I'm not using
indexes yet. I do a query using psql like "select * from mytable" and pipe
it to a file. It takes about a second or so to complete and I notice the CPU
idle time goes to maybe 50%. Pretty fast. Doing the same query using the
JDBC driver takes the CPU idle to 0% for about 90 seconds, then finally
returns. A code fragment...
String sql = "select * from mytable";
Connection conn = get_con(); // uses a DbConnectionBroker class. Performs
the same with or without this class.
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
more = rs.next();
Trace("Finished Query. Filling Vector." );
while (more) {
count ++;
vector.addElement((new Long(rs.getLong("ID")).toString()));
vector.addElement(rs.getString("Name"));
etc...
more = rs.next();
}
rs.close();
stmt.close();
...
The executeQuery(sql) statement takes about 90 secs, then I see the Trace
output, then the vector operations take about 10-15 secs. I suppose I can
live with the Vector op time, if there is no more effecient way of getting
query results, (I haven't really looked into it), but 90 secs for executing
the query seems unreasonable.
Anyone else experience this type of thing?
Thanks in Advance.
Rich.
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Subject: Re: JDBC Query performance
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