Unsorted SQL Results Can Make Strategy Outputs Appear Inconsistent
Summary
A trader reports that a stock-selection strategy using TA-Lib indicators produces different results each time it is run. The response points to an SQL query in one module that lacks an explicit sort order as the likely cause. When rows arrive in an unspecified order, downstream processing can produce varying outputs even if the indicator signals themselves are stable.
The exchange also reports that another user obtained consistent results and saw unchanged values in the signal column. This is a brief troubleshooting suggestion rather than a demonstrated diagnosis: the underlying strategy and query are not included here, and no controlled comparison is provided. For reproducibility, inspect the order in which records enter later modules and specify a deterministic sort where sequence matters; then compare the resulting signals and selections across runs.
Key ideas
- An SQL query without explicit ordering may return rows in an unstable sequence.
- Downstream strategy calculations can appear inconsistent if they depend on input order.
- A respondent reports stable strategy and signal results, but the document does not show the code or verify the diagnosis.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.