Re: first extent and next extent

Please respond to jjdai@pek-co.cn.dhl.com To: informix-list@iiug.org cc: (bcc: Jack Parker/Boston50/Epsilon) Subject: first extent and next extent Hi, I want to know that is there a system table include first and next extent size information ? SELECT tabname, fextsize, nextsize from systables; Refer to chapter 2 of the SQL Reference manual. and how can i keep the origin extent size during dbexport and dbimport easily ? You might be able to do a dbexport -ss, you can certainly overwrite the DDL generated by the dbexport using a dbschema -ss (server specific) which generates fragmentation and extent allocation code. and how can i change the first extent size after dbimport (for i know change next extent size by alter table statement)? There is no DDL command per se to alter the first extent size. It's moot. First extent has already been allocated once the table has been built - if you mean how do you re-write the table into a larger (or smaller) first extent, you can unload, drop and reload or you can 'ALTER INDEX foo TO CLUSTER. This last statement re-writes the data pages that the table occupies and hence changes the size of the first extent. THe only catch is that there should be enough unfragmented pages to write it to so that it doesn't wind up fragmenting all over the place again. Since a dbimport works in serial you should not have an issue with first extent size - each table will grab the extents it needs as it loads, if it runs out of space then it will grab a next size, adjacent to the first size, append it to the first extent and change the systables entry to note that change in first extent size. Of course there are times... HTH cheers j. -------------------==== Posted via Deja News ====----------------------- http://www.dejanews.com/ Search, Read, Post to Usenet