How to

Hello

I have a strange behaviour :
time psql -d db_cathline -c "SELECT * FROM v_stock_status;"

real 0m5.780s
user 0m0.090s
sys 0m0.020s

time psql -d db_cathline -c "SELECT * FROM v_stock_status WHERE remain_qty != 0;"

real 0m56.075s
user 0m0.070s
sys 0m0.030s

Why with the clause WHERE the time are 10x greater than ? How can I work around this ?

# select version();
                                                   version                                                  
-------------------------------------------------------------------------------------------------------------
PostgreSQL 8.4.7 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.4.real (Ubuntu 4.4.3-4ubuntu5) 4.4.3, 64-bit
(1 ligne)

Regards
Guy