improve feature merging ?

[etienneJr]

I am wondering whether the parameters for feature merging have been optimized ? In config.json I only found combine_below parameters and no combine_polygons_below parameters. On another discussion, I read :

Merging features can bring tile size down by a factor of four.

But when I removed all feature merging (by putting combine_below: 0), the weight increased by only +3%, not at all by x4. My conclusion is that there is very little feature merging with this config, right ? I've thought about changing the settings to increase feature merging, but I'm not sure how to do it properly. Are there any rules to follow? Can you provide an example?

[etienneJr]

I did a complete study here with several merging strategies and including ids or not. On my test cases (French Riviera, Colorado), I observed:

• the combine_xxx options included in main branch decrease weight by -3% compared to no merging at all
• it is possible to decrease size by -17% (compared to main branch) if you activate all merging options on all layers and all levels. But the calculation time is greatly increased.
• there is no incompatibility between merging features and including ids