Queries take long long(10 sec.) time running

Hi,

I have a "vertical" database schema running with an webapp. I query
this database in the webapp rotating the vertical schema with a
view(something like a pivot view)

I know that this type of operation is very expensive, but I have the
webapp running with acceptable response time for 45 days(machine
uptime). Now the queries started to take much much time to execute. I
use a VPS with 512MB memory, and I have Apache2, PostgreSQL 8.4, MySQL
5. The webapp don't have high traffic, have about 700 visits per
day...

I've run "top" and I see that the server is using a lot of swap. I
have ordered the "top" to give me the used swap, the result is this:

[code]
top - 09:24:13 up 49 days, 22:44, 3 users, load average: 0.15, 0.12, 0.13
Tasks: 123 total, 1 running, 122 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0%us, 0.0%sy, 0.0%ni, 96.6%id, 3.3%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 500452k total, 490576k used, 9876k free, 496k buffers
Swap: 524284k total, 343664k used, 180620k free, 32428k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP
COMMAND
1881 mysql 20 0 929m 2024 0 S 0.0 0.4 142:11.73 927m
mysqld
11093 root 20 0 275m 56 0 S 0.0 0.0 0:03.46 275m
httpd
19462 apache 20 0 280m 6704 1796 S 0.0 1.3 0:02.00 273m
httpd
11103 apache 20 0 280m 7076 1740 S 0.0 1.4 0:07.80 273m
httpd
11095 apache 20 0 280m 7544 1788 S 0.0 1.5 0:08.70 273m
httpd
11260 apache 20 0 280m 7548 1548 S 0.0 1.5 0:07.94 273m
httpd
11096 apache 20 0 280m 7728 1588 S 0.0 1.5 0:08.45 272m
httpd
12668 apache 20 0 280m 7660 1804 S 0.0 1.5 0:07.30 272m
httpd
11293 apache 20 0 280m 7908 1800 S 0.0 1.6 0:08.59 272m
httpd
12669 apache 20 0 280m 8052 1860 S 0.0 1.6 0:07.69 272m
httpd
11099 apache 20 0 277m 4940 1720 S 0.0 1.0 0:08.64 272m
httpd
11297 apache 20 0 280m 8100 1884 S 0.0 1.6 0:09.00 272m
httpd
11102 apache 20 0 280m 8148 1920 S 0.0 1.6 0:09.34 272m
httpd
12672 apache 20 0 280m 8172 1804 S 0.0 1.6 0:07.62 272m
httpd
12113 apache 20 0 280m 8220 1804 S 0.0 1.6 0:07.87 272m
httpd
11100 apache 20 0 280m 8348 1940 S 0.0 1.7 0:08.70 272m
httpd
12663 apache 20 0 278m 7188 1940 S 0.0 1.4 0:07.66 271m
httpd
19350 apache 20 0 277m 6148 1936 S 0.0 1.2 0:07.23 271m
httpd
11105 apache 20 0 280m 8928 2412 S 0.0 1.8 0:08.08 271m
httpd
1960 apache 20 0 279m 7912 2108 S 0.0 1.6 0:05.63 271m
httpd
11287 apache 20 0 276m 5176 1936 S 0.0 1.0 0:08.66 271m
httpd
14813 apache 20 0 280m 9336 2424 S 0.0 1.9 0:03.00 271m
httpd
1729 root 20 0 242m 396 252 S 0.0 0.1 1:14.37 242m
rsyslogd
11304 postgres 20 0 218m 15m 15m S 0.0 3.2 1:34.18 203m
postmaster
11323 postgres 20 0 218m 20m 16m S 0.0 4.2 1:58.70 198m
postmaster
20149 postgres 20 0 218m 22m 17m S 0.0 4.7 0:07.35 195m
postmaster
11360 postgres 20 0 218m 23m 17m S 0.0 4.8 1:14.27 194m
postmaster
11604 postgres 20 0 218m 23m 17m S 0.0 4.9 1:43.92 194m
postmaster
11531 postgres 20 0 218m 24m 17m S 0.0 4.9 2:29.91 194m
postmaster
11628 postgres 20 0 218m 24m 17m S 0.0 5.0 2:46.56 194m
postmaster
11437 postgres 20 0 218m 24m 17m S 0.0 4.9 1:38.11 194m
postmaster
28295 postgres 20 0 188m 3364 2920 S 0.0 0.7 0:00.09 184m
postmaster
13465 postgres 20 0 184m 140 96 S 0.0 0.0 15:07.25 183m
postmaster
13466 postgres 20 0 184m 596 300 S 0.0 0.1 6:14.63 183m
postmaster
13460 postgres 20 0 184m 340 220 S 0.0 0.1 5:14.39 183m
postmaster
13555 postgres 20 0 218m 35m 17m S 0.0 7.3 1:28.89 183m
postmaster
13464 postgres 20 0 184m 3332 3168 S 0.3 0.7 16:38.80 180m
postmaster
11761 postgres 20 0 218m 37m 17m S 0.0 7.7 1:41.28 180m
postmaster
11560 postgres 20 0 218m 38m 17m S 0.0 7.8 1:37.13 180m
postmaster
12914 postgres 20 0 218m 39m 17m S 0.0 8.1 1:49.34 179m
postmaster
11305 postgres 20 0 202m 24m 17m S 0.0 5.0 1:31.30 178m
postmaster
29837 postgres 20 0 188m 10m 8332 S 0.0 2.1 0:01.42 178m
postmaster
12666 postgres 20 0 218m 40m 17m S 0.0 8.4 0:59.64 177m
postmaster
19639 postgres 20 0 216m 41m 17m S 0.0 8.5 1:38.68 175m
postmaster
11373 postgres 20 0 218m 44m 18m S 0.0 9.2 1:39.24 173m
postmaster
12196 postgres 20 0 195m 23m 16m S 0.0 4.8 1:15.28 172m
postmaster
2313 postgres 20 0 202m 31m 18m S 0.0 6.4 1:09.09 171m
postmaster
14947 postgres 20 0 218m 47m 18m S 0.0 9.7 0:30.29 170m
postmaster
[/code]

This "top" result is ordered by swap.

This is enough information for some clues on how to increase the
response time in queries?

Best Regards,