SET EXPLAIN question

-- When I was checking through the sqexplain.out for an application I am converting to use Informix I noticed some unexpectedly high Estimated Cost values on statements where I use ROWID in the WHERE clause. For example: QUERY: ------ SELECT TABLE_DESC , ASSOC_REC FROM MSF010 WHERE ROWID = ? Estimated Cost: 1469 Estimated # of Rows Returned: 1 1) ats.msf010: INDEX PATH (1) Index Keys: ROWID Lower Index Filter: ats.msf010.ROWID = 194830 The manual tells me that using ROWID is 'the simplest form of nonsequential access' and since the 'rowid value specifies the physical location of the row and its page' I thought this would not require anything other than a direct read with an Estimated Cost of 1. The Estimated Cost appears constant for all accesses to a table and varies according to the size of the table. The table ats.msf010 contains 15,883 records. Is the value reported by SET EXPLAIN invalid or do I have cause to worry? Also, is there a recommended definition for a COBOL host variable that will hold the ROWID value? And will the definition affect the Estimated Cost in any way? I am using Online V6. Regards, Chris ------------------------------------------------------------------------------ Chris Wegener Mincom Pty Ltd, Database Consultant Wyandra Street, | | | | | | chrispw@tenmail.mincom.oz.au Teneriffe, Brisbane, | | | | | | Phone: +61 7 303 3333 X2288 Queensland, | | | | | | Fax: +61 7 303 3232 Australia 4005 |M |I |N |C |O |M ------------------------------------------------------------------------------