Dojo,
Is there a limitation on the number of bars/columns that can be displayed in this component ?


There is a hard limit of 1,000 rows. Since you can add a bar/column for every numeric column, the theoretical limit is 1,000 × the number of numeric columns in your result. However, screen real estate is the practical bottleneck, as we can't draw two bars on a single pixel. Therefore, the actual limit is min(innerChartWidthPx, 1000 * numberOfNumericColumns).
The more bars/columns you have, the narrower they will be rendered. Ultimately, the total number of bars determines the available width for each individual one.
When plotting two numeric columns (second image), the width of the bars/columns reduces to accommodate more. Wondering if this is also possible when a single numeric column is plotted ? ( DM 10.6.8)