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Informix Error -739

Cause and resolution

Confidence must be in the range [0.80, 0.99] (inclusive).

If the value of the confidence desired is greater than 0.99, use HIGH mode. A value of less than 0.80 is not allowed because it will probably yield a poor distribution. If you are reducing the confidence to reduce the time that is required to execute the UPDATE STATISTICS statement, consider using a larger resolution value.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-739 fires when UPDATE STATISTICS's confidence value (the second RESOLUTION argument, in MEDIUM mode) falls outside [0.80, 0.99] — per the official guidance, a value above 0.99 should use HIGH mode instead, and a value below 0.80 is rejected outright since it would likely produce a poor-quality distribution.

  1. A confidence value above 0.99, per the official guidance — the documented fix is to switch to HIGH mode rather than push confidence any higher in MEDIUM mode.
  2. A confidence value below 0.80, per the official guidance — rejected as too low to produce a useful distribution, not adjustable by any other parameter.
  3. An attempt to speed up UPDATE STATISTICS by lowering confidence past the floor, per the official guidance's own suggested alternative — use a larger resolution value instead, which achieves a similar speed benefit without falling outside the valid confidence range.
Solutions / Resolution
  1. Use a confidence value between 0.80 and 0.99 inclusive, per the official guidance.
  2. Switch to HIGH mode if confidence above 0.99 is genuinely needed, per the official guidance — HIGH mode builds from the complete data, so it doesn't have a confidence parameter at all (see -737).
  3. If the goal was reducing execution time, increase the resolution value instead of pushing confidence below 0.80, per the official guidance's own suggested alternative.
Examples
Confidence too low
UPDATE STATISTICS MEDIUM RESOLUTION 0.5 0.75 FOR TABLE orders;
-- -739: 0.75 is below the 0.80 floor
Corrected — within range
UPDATE STATISTICS MEDIUM RESOLUTION 0.5 0.90 FOR TABLE orders;
Or corrected — HIGH mode for confidence above 0.99
UPDATE STATISTICS HIGH RESOLUTION 0.5 FOR TABLE orders;
Diagnostic Checks
  1. Check the confidence value against the [0.80, 0.99] range, and either adjust it, increase the resolution instead, or switch to HIGH mode.
Related Errors / Related Topics
  • -737 — "The confidence value and the SAMPLING SIZE clause are not valid for the HIGH mode of the UPDATE STATISTICS statement." Confirms why confidence above 0.99 needs HIGH mode rather than a higher MEDIUM-mode value — HIGH mode doesn't take a confidence value at all.
  • -740 — "Resolution must be greater than 0.005 and less than, or equal to, 10.0." A related UPDATE STATISTICS parameter-range restriction, on the resolution value rather than confidence.

Below 0.80 isn't adjustable — raise it into range, or increase resolution instead if speed was the actual goal.