dbaclass=# SELECT a.query,p.phase, p.blocks_total,p.blocks_done,p.tuples_total, p.tuples_done FROM pg_stat_progress_create_index p JOIN pg_stat_activity a ON p.pid = a.pid;

-[ RECORD 1 ]+-------------------------------
query        | reindex index test_idx;
phase        | building index: scanning table
blocks_total | 61281
blocks_done  | 15331
tuples_total | 0
tuples_done  | 0

(or)

dbaclass=# select pid,datname,command,phase,tuples_total,tuples_done,partitions_total,partitions_done from pg_stat_progress_create_index;

-[ RECORD 1 ]-