This script uses the pgstattuple extension to get both table and b-tree index bloat information. Since it's actually scanning the table, it can take longer than other queries that try and do estimates based on statistics. But it does give you very accurate information. You can also just use pgstattuple directly without this script, but you do have to run it individually on the table then each index. The script can scan the table and all its indexes in one step and give you a full summary.
