Below are what I think are the relevant snippets from the analyzer, table A reports about 50% unused bytes in its pages, while table B reports just 0.3%... Table A pages are significantly non-sequential. I am currently using 4k pages (running under Windows), would using larger pages help ? The database as a whole is at 4.6% unused bytes, which is quite good, and table A is the only one with such a ratio of unused bytes, but it is also the only really "dynamically updated" table, other tables are more like indexed logs or regularly regenerated views like table B. I can send you the whole file by mail if needed. Thanks ~~~~~ /** Disk-Space Utilization Report Page size in bytes................................ 4096 Pages in the whole file (measured)................ 90532790 Pages in the whole file (calculated).............. 90528869 Pages that store data............................. 90528868 99.996% Pages on the freelist (per header)................ 0 0.0% Pages on the freelist (calculated)................ 3922 0.004% Pages of auto-vacuum overhead..................... 0 0.0% Number of tables in the database.................. 45 Number of indices................................. 23 Number of defined indices......................... 14 Number of implied indices......................... 9 Size of the file in bytes......................... 370822307840 Bytes of user payload stored...................... 124189467598 33.5% *** All tables and indices **************************************************** Percentage of total database...................... 99.996% Number of entries................................. 14551461088 Bytes of storage consumed......................... 370806243328 Bytes of payload.................................. 285702356053 77.0% Bytes of metadata................................. 68107134984 18.4% Average payload per entry......................... 19.63 Average unused bytes per entry.................... 1.17 Average metadata per entry........................ 4.68 Average fanout.................................... 175.00 Maximum payload per entry......................... 4033 Entries that use overflow......................... 7 0.0% Index pages used.................................. 516031 Primary pages used................................ 90012830 Overflow pages used............................... 7 Total pages used.................................. 90528868 Unused bytes on index pages....................... 228253065 10.8% Unused bytes on primary pages..................... 16768481486 4.5% Unused bytes on overflow pages.................... 17740 61.9% Unused bytes on all pages......................... 16996752291 4.6% *** All tables **************************************************************** Percentage of total database...................... 44.7% Number of entries................................. 4881591576 Bytes of storage consumed......................... 165647638528 Bytes of payload.................................. 124189475776 75.0% Bytes of metadata................................. 38496387527 23.2% Average payload per entry......................... 25.44 Average unused bytes per entry.................... 0.61 Average metadata per entry........................ 7.89 Average fanout.................................... 333.00 Maximum payload per entry......................... 4030 Entries that use overflow......................... 0 0.0% Index pages used.................................. 121285 Primary pages used................................ 40320033 Overflow pages used............................... 0 Total pages used.................................. 40441318 Unused bytes on index pages....................... 63087082 12.7% Unused bytes on primary pages..................... 2898688143 1.8% Unused bytes on overflow pages.................... 0 Unused bytes on all pages......................... 2961775225 1.8% *** All indices *************************************************************** Percentage of total database...................... 55.3% Number of entries................................. 9669869512 Bytes of storage consumed......................... 205158604800 Bytes of payload.................................. 161512880277 78.7% Bytes of metadata................................. 29610747457 14.4% Average payload per entry......................... 16.70 Average unused bytes per entry.................... 1.45 Average metadata per entry........................ 3.06 Average fanout.................................... 126.00 Maximum payload per entry......................... 4033 Entries that use overflow......................... 7 0.0% Index pages used.................................. 394746 Primary pages used................................ 49692797 Overflow pages used............................... 7 Total pages used.................................. 50087550 Unused bytes on index pages....................... 165165983 10.2% Unused bytes on primary pages..................... 13869793343 6.8% Unused bytes on overflow pages.................... 17740 61.9% Unused bytes on all pages......................... 14034977066 6.8% *** Table A and all its indices ************************************** Percentage of total database...................... 0.36% Number of entries................................. 61907152 Bytes of storage consumed......................... 1347289088 Bytes of payload.................................. 476164577 35.3% Bytes of metadata................................. 336657088 25.0% Average payload per entry......................... 7.69 Average unused bytes per entry.................... 8.63 Average metadata per entry........................ 5.44 Average fanout.................................... 193.00 Maximum payload per entry......................... 13 Entries that use overflow......................... 0 0.0% Index pages used.................................. 1702 Primary pages used................................ 327226 Overflow pages used............................... 0 Total pages used.................................. 328928 Unused bytes on index pages....................... 2709763 38.9% Unused bytes on primary pages..................... 531757660 39.7% Unused bytes on overflow pages.................... 0 Unused bytes on all pages......................... 534467423 39.7% *** Table A w/o any indices ****************************************** Percentage of total database...................... 0.23% Number of entries................................. 30953576 Bytes of storage consumed......................... 847339520 Bytes of payload.................................. 176578512 20.8% Bytes of metadata................................. 242331668 28.6% B-tree depth...................................... 4 Average payload per entry......................... 5.70 Average unused bytes per entry.................... 13.84 Average metadata per entry........................ 7.83 Average fanout.................................... 185.00 Non-sequential pages.............................. 101735 49.2% Maximum payload per entry......................... 9 Entries that use overflow......................... 0 0.0% Index pages used.................................. 1113 Primary pages used................................ 205757 Overflow pages used............................... 0 Total pages used.................................. 206870 Unused bytes on index pages....................... 2335945 51.2% Unused bytes on primary pages..................... 426093395 50.6% Unused bytes on overflow pages.................... 0 Unused bytes on all pages......................... 428429340 50.6% *** Table B and all its indices **************************************** Percentage of total database...................... 0.41% Number of entries................................. 92780529 Bytes of storage consumed......................... 1501921280 Bytes of payload.................................. 1093102743 72.8% Bytes of metadata................................. 405432075 27.0% Average payload per entry......................... 11.78 Average unused bytes per entry.................... 0.04 Average metadata per entry........................ 4.37 Average fanout.................................... 295.00 Maximum payload per entry......................... 21 Entries that use overflow......................... 0 0.0% Index pages used.................................. 1241 Primary pages used................................ 365439 Overflow pages used............................... 0 Total pages used.................................. 366680 Unused bytes on index pages....................... 286291 5.6% Unused bytes on primary pages..................... 3100171 0.21% Unused bytes on overflow pages.................... 0 Unused bytes on all pages......................... 3386462 0.23% *** Table B w/o any indices ******************************************** Percentage of total database...................... 0.20% Number of entries................................. 30926843 Bytes of storage consumed......................... 758759424 Bytes of payload.................................. 538805686 71.0% Bytes of metadata................................. 217693793 28.7% B-tree depth...................................... 4 Average payload per entry......................... 17.42 Average unused bytes per entry.................... 0.07 Average metadata per entry........................ 7.04 Average fanout.................................... 358.00 Non-sequential pages.............................. 10 0.005% Maximum payload per entry......................... 21 Entries that use overflow......................... 0 0.0% Index pages used.................................. 516 Primary pages used................................ 184728 Overflow pages used............................... 0 Total pages used.................................. 185244 Unused bytes on index pages....................... 271807 12.9% Unused bytes on primary pages..................... 1988138 0.26% Unused bytes on overflow pages.................... 0 Unused bytes on all pages......................... 2259945 0.30% ~~~~~