Re: Help with sizing tablespace files & extents

From: Dave Mausner <dma956_at_lulu.acns.nwu.edu>
Date: 1995/10/17
Message-ID: <461656$6k7_at_news.acns.nwu.edu>#1/1


[q1: how to allocate files of a big database?]

current opinion is that you should make files of a standard size, such as 1Gb each. thus a 3Gb tablespace would have three files. smaller files (e.g., 500Mb) would not be significantly worse, and may have advantages for restoration and recovery time if a file is damaged. the number of extents is obviously larger, but it is felt that the extent-switch time is now an extremely small component of the data transfer time, given such fast cpus and large disk arrays. the one-extent-per-table thesis arose before the era of gigabyte tables.

[q2: how to exp/imp legacy data]

capture the db structure by performing an export with rows=no option. then drop all your legacy indexes to regain some disk space. that may allow your export with rows=yes to succeed. (p.s., you will have to drop the index tablespace; aren't you glad you created one separately from the data?) after exp, drop old tablespaces and create your nice clean big ones. import your SECOND export file (no indexes, with data) then import your FIRST export file (indexes, no data) with ignore=yes option on both of these imports. Received on Tue Oct 17 1995 - 00:00:00 CET

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