This SELECT hangs one of its three tables

The following SELECT runs for 25 minutes until outputing its first row. During the last 10 minutes of its execution, all new SELECT's on the table 'periodt' hang. SELECT's on the other tables, 'batch' and 'timecard', do not. If I terminate the hung SELECT on 'periodt' with an interupt, I get this error message: 242: Could not open database table (root.periodt). 4: Interrupted system call Once the main SELECT outputs its first row, the hung SELECT on 'periodt' clears and outputs its first row. I was the only user during the test. The tests were run on a Sequent Unix multiprocessor computer using Informix SE(standard engine). The test is repeatable. Periodt table is 2k in size, batch is 3k, and timecard is 47 MB. This is the SELECT that hangs things. Fields that begin with 't' are from timecard, 'b' from batch, and 'p' from periodt. - - - select tmatter, tworkhrs, tworkdol, tworkdt, twoper, tbillhrs, tbilldol, tbilldt, tbiper, peendt from timecard, batch, periodt where tbatch = bbatch and twoper = pe and tstatus <> "ADE" and (bfindt is not null or tstatus = "AD") order by tmatter Why does it do this? -- Bruce Momjian | 830 Blythe Avenue root%candle.uucp@bts.com | Drexel Hill, Pennsylvania 19026 + If your life is a hard drive, | (215) 353-9879(w) + Christ can be your backup. | (215) 853-3000(h)