Re: HASH JOIN

Posted in 2000

Maria Seagull — Fri, 11 Feb 2000 11:11:28 -0800 (PST) — source: Informix-list mailing list archive (1991-1998)

>mips <mips@zg.tel.hr> wrote in message >news:en88assp4cnu821fv36te6gie6uha17dem@4ax.com... >When and why Informix uses DYNAMIC HASH JOIN? When: i) Atleast one of the join tables hasn't got index on the join columns. OR ii) The server would have to read a large no. of rows in both tables. Why: Because in the above conditions, creating a hash table and then joining is efficient. Please note that the hash table is usually stored in the virtual portion of the shared memory or in the temp space of disks. HTH. __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com