PostgreSQL – Execute Query from psql Without Waiting for Result

Maybe it would be easiest to run a psql in the background, with it set to execute stdin, and connect its stdin to a named pipe. Then you can continually push data into that pipe, and finally push "end; \quit". Something like:

#!/bin/sh

psql_pipe=/tmp/psql$$
mkfifo -m 600 $psql_pipe
psql < $psql_pipe &
exec 3>$psql_pipe
psql_pid=$!

echo "> Started psql (pid=$psql_pid) reading from $psql_pipe"
trap '
  kill $psql_pid
  rm -f $psql_pipe
' EXIT

echo "begin;" >&3

echo "select now();" >&3

sleep 2

echo "select now();" >&3

sleep 2

echo "end; \quit" >&3

wait $psql_pid

Note that you can't simply do echo "sql" >$psql_pipe since the EOF would be transmitted to psql, which would then exit early-- the shell script has to keep its fd open.

You sort of answer your own question when you say you have no pooling but...

This is not an answer out of the box, with all client/db stuff you may need to do some work to determine exactly what is amiss

backup postgresql.conf changing

log_min_duration_statement to 0 
log_destination = 'csvlog'              # Valid values are combinations of      
logging_collector = on                # Enable capturing of stderr and csvlog 
log_directory = 'pg_log'                # directory where log files are written,
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' # log file name pattern,        
debug_print_parse = on
debug_print_rewritten = on
debug_print_plan output = on
log_min_messages = info (debug1 for all server versions prior to 8.4)

Stop and restart your database server ( reload may not pick up the changes ) Reproduce your tests ensuring that the server time and client times match and that you record the start times etc.

copy the log file off an import into editor of your choice (excel or another spreadsheet can be useful for getting advance manipulation for sql & plans etc)

now examine the timings from the server side and note:

is the sql reported on the server the same in each case

if the same you should have the same timings

is the client generating a cursor rather than passing sql

is the query arriving on the server when you believe it should do

is one driver doing a lot of casting/converting between character sets or implicit converting of other types such as dates or timestamps.

and so on

The plan data will be included for completeness, this may inform if there are gross differences in the SQL submitted by the clients.