Re: How does "ALTER TALBE" work?

Posted in 1998

Topics: Performance & Tuning, Transactions, Locking & Isolation, Migration, Import/Export & Data Conversion

alastl@ctnet.net — Fri, 24 Apr 1998 08:53:31 -0600 — source: Informix-list mailing list archive (1991-1998)

In article <353DD1DC.6FD234CD@cs-controlling.de>, "Volker Fr'nkle" <VFraenkle@cs-controlling.de> wrote: > > Hello, > here is a little technical question. > > Is it true, that INFORMIX copies the whole data from the old table to > the new table and then dropps the old table? It's sad, but true. My recommendations: 1. Drop all indices before altering table. 2. Turn off transaction logging, if possible. Both of these will increase the performance and reduce the disk usage of ALTER TABLE. Bear in mind that if you are working on a database which is in use by others then turning off logging becomes more difficult (if not impossible). > > Or is there any different technique? Unload. Drop old table. Create with new schema (no indices). Load. Build indices on new table. John Prideaux alastl@ctnet.net -----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/ Now offering spam-free web-based newsreading