1. UNLOGGED tables 　 Operating System: Suse-Linux 10.2 x86_64 　
　 2. 10GB shared buffers 　 Hardware : 4 core (Intel(R) Xeon(R) CPU L5408 @ 2.13GHz) 　 　
　 3. Number of tuples - 2,000,000 RAM : 24GB 　 　
　 4. Single connection 　 　 　
　 5. All columns INT data type 　 　 　 　 　 　
　 　 　
　 STEP-1: INSERT WITH TAILING COLUMNS WITH NULL 　
　 800 cols - 600 nulls 800 cols - 300 nulls 300 cols - 150 nulls 300 cols - 250 nulls 　
　 Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) 　
Original Code 9659.534 250000 70964.223 666667 7139.723 166667 3633.513 66667 　
9660.523 250000 71137.35 666667 7181.817 166667 3690.42 66667 　
9624.601 250000 71493.857 666667 7164.65 166667 3663.35 66667 　
9708.767 250000 71358.109 666667 7027.79 166667 3680.935 66667 　
9709.173 250000 71560.704 666667 7008.517 166667 3690.72 66667 　
9672.5196 250000 71302.8486 666667 7104.4994 166667 3671.7876 66667 　
　 　 　
Trim Tailing NULLs pathch 8728.914 222223 69659.69 666667 6942.56 166667 3388.882 58824 　
8706.79 222223 69646.359 666667 6908.025 166667 3336.522 58824 　
8589.396 222223 69853.287 666667 6841.875 166667 3359.254 58824 　
8729.362 222223 69277.953 666667 6891.575 166667 3267.011 58824 　
8685.041 222223 69728.952 666667 6914.374 166667 3325.61 58824 　
8687.9006 222223 69633.2482 666667 6899.6818 166667 3335.4558 58824 　
　 　 　
　 10.18% 11.11% 2.34% 0.00% 2.88% 0.00% 9.16% 11.76% 　
　 　 　
　 　
　 STEP-2: AFTER STEP-1; UPDATE LAST COLUMN WITH NON-NULL
Example: UPDATE TBL SET F800 = 5; (for 800 columns table)		 　
　 800 cols - 600 nulls 800 cols - 300 nulls 300 cols - 150 nulls 300 cols - 250 nulls 　
Original Code Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) 　
44966.365 500000 142652.134 1333334 23038.094 333334 15962.495 135633 　
44143.511 500000 141065.271 1333334 23836.695 333334 15989.269 135633 　
44766.451 500000 133314.792 1333334 23654.263 333334 16025.056 135633 　
44625.44233 500000 139010.7323 1333334 23509.684 333334 15992.27333 135633 　
　 　 　
Trim Tailing NULLs pathch 41883.931 472223 130009.289 1333334 23914.548 333334 16085.394 127790 　
41287.726 472223 131517.017 1333334 23014.507 333334 16222.045 127790 　
41483.067 472223 133212.223 1333334 22042.874 333334 16396.235 127790 　
41551.57467 472223 131579.5097 1333334 22990.643 333334 16234.558 127790 　
　 　 　
　 6.89% 5.56% 5.35% 0.00% 2.21% 0.00% -1.52% 5.78% 　
　 　 　
　 　
　 STEP-3: AFTER STEP-2; UPDATE OPERATION LAST COLUMN WITH NULL
Example: UPDATE TBL SET F800 = NULL; (for 800 columns table)		 　
　 800 cols - 600 nulls 800 cols - 300 nulls 300 cols - 150 nulls 300 cols - 250 nulls 　
Original Code Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) Execution time(ms) space (pages) 　
46606.223 750000 141029.26 2000000 23655.586 500000 16300.106 202299 　
46741.412 750000 142013.506 2000000 23983.859 500000 16466.762 202299 　
45350.242 750000 131936.86 2000000 23305.943 500000 16294.847 202299 　
46232.62567 750000 138326.542 2000000 23648.46267 500000 16353.905 202299 　
　 　 　
Trim Tailing NULLs pathch 40618.736 694445 131992.67 2000000 23853.028 500000 14758.747 186613 　
41612.561 694445 134703.781 2000000 23730.218 500000 14720.166 186613 　
39523.141 694445 136116.766 2000000 22823.762 500000 14605.663 186613 　
40584.81267 694445 134271.0723 2000000 23469.00267 500000 14694.85867 186613 　
　 　 　
　 12.22% 7.41% 2.93% 0.00% 0.76% 0.00% 10.14% 7.75%