Routing congestion data can't be stored in DEF and so is not available on reload. When https://github.com/The-OpenROAD-Project/OpenLane/issues/1159 is fixed it will work. In the meantime you would have to run the global router to see it.

@Matt Liberty It looks like the issue is now closed and merged into openlane. What is the recommended procedure now for opening up the database with congestion information? I was able to update openlane and run the openroad gui, and I went into my issue_reproducible/results/placement and tried calling

read_db issue_reproducible/results/placement/user_project_wrapper.buffers_removed.odb

but I still get an error on trying to enable the routing congestion heat map:

[WARNING GUI-0066] Heat map "Routing Congestion" has not been populated with data.

Is there a particular database file that would store congestion information for global routing failures giving a

[ERROR GRT-0118] Routing congestion too high. Check the congestion heatmap in the GUI.

The congestion data is saved in the odb after global routing and should be available thereafter. In ORFS I use it regularly from the final db