Hello, Many thanks for the valuable suggestions and insights. The defaults enable_bitmapscan and enable_seqscan were altered by my friend. He already re enabled them (maybe even while I was trying some of the queries). The machine is a P4 3.2GHz, 1 GBram, sata hd, windows 2000. I did not used pg on win before to have any advice to my friend. The previously attached file contains SOME relevant info from the psql session, in order to not clutter file. When some server parameter was modified (at least by me) and server restarted, a new sholl parameter was issued to show the new value. Firebird is running at the same machine. As you can see by the session log, indexes were created on the columns used and tables was first clustered on the indexes actually used by the query. The subsequent cluster commands only recluster on the same indexes previously clustered. shared_buffers was increased from 1000 to 16384 pages effective_cache_size was increased from 1000 to 65535 pages and at the final steps REDUCED to 8192 pages work_mem was increased from 1024 first to 16384 KB and then to 65535 KB. The first 2 parameters reduced time 18%. work_mem reduced time almost 66%. But work_mem easily can exhaust ram with many users connected, as each connection query will use this amount of memory (if I can remember). How much it can grow at this 1 gbram win machine? Some of the docs I already read suggested that indexes should be entirely contained in ram. How to dimension the parameters? Other docs adviced that some memory parameters could actually degrade performance if too big. There are peak points at the performance curve by adjusting mem parameters. I hope tomorrow execute explain with the bitmapscan and seqscan enabled. bitmapscans are almost always faster? The data, as far I know, are a sample real app data (hey, if and when in production it will be even large?). They are almost true random as my friend informed, and according to him, cluster should not really be of benefit. It seems confirmed by the various explain analyze commands before and after clustering. Any suggestions? Do you see some obvious error on the steps at the previous session log file? It seems that Firebird windows can use adequately as much ram it finds and postgresql windows can not. How dimension ram to the indexes? Only by trial and error? I tried some suggested values found at some tuning docs suitable to the available system ram. Thanks Andre Felipe
