Hello! I tried to use your program and catch error when used sample from your documentation:

postgres=# SELECT application_name, userid AS user_name, datname AS database_name, substr(query,0, 50) AS query, calls, client_ip
postgres-# FROM pg_stat_monitor;
ОШИБКА: столбец "application_name" не существует
LINE 1: SELECT application_name, userid AS user_name, datname AS dat...
^
postgres=# \d pg_stat_monitor;
View "public.pg_stat_monitor"
Column | Type | Collation | Nullable | Default
--------------------+------------------------+-----------------------------
bucket | integer | | |
bucket_start_time | timestamp with time zone | | |
userid | oid | | |
dbid | oid | | |
client_ip | inet | | |
queryid | text | | |
query | text | | |
plans | bigint | | |
plan_total_time | double precision | | |
plan_min_timei | double precision | | |
plan_max_time | double precision | | |
plan_mean_time | double precision | | |
plan_stddev_time | double precision | | |
calls | bigint | | |
total_time | double precision | | |
min_time | double precision | | |
max_time | double precision | | |
mean_time | double precision | | |
stddev_time | double precision | | |
rows | bigint | | |
shared_blks_hit | bigint | | |
shared_blks_read | bigint | | |
shared_blks_dirtied | bigint | | |
shared_blks_written | bigint | | |
local_blks_hit | bigint | | |
local_blks_read | bigint | | |
local_blks_dirtied | bigint | | |
local_blks_written | bigint | | |
temp_blks_read | bigint | | |
temp_blks_written | bigint | | |
blk_read_time | double precision | | |
blk_write_time | double precision | | |
resp_calls | text[] | | |
cpu_user_time | double precision | | |
cpu_sys_time | double precision | | |
tables_names | text[] | | |