BUG #17179: EOF detected

The following bug has been logged on the website:

Bug reference: 17179
Logged by: Никита Шумилов
Email address: 66666666nikita(at)gmail(dot)com
PostgreSQL version: 12.6
Operating system: Ubuntu
Description:

Query running for more than 30 minutes are disconnected
SELECT pg_sleep(1820)
SSL SYSCALL error: EOF detected

Increased timeouts tcp_user_timeout, tcp_keepalives_interval didn't help.

Configuration:
autovacuum_naptime 60 s
timezone_abbreviations Default
client_encoding UNICODE
vacuum_freeze_min_age 50000000
search_path "$user", public
password_encryption md5
ssl_passphrase_command
ssl_key_file /etc/ssl/private/ssl-cert-snakeoil.key
allow_system_table_mods off
ident_file /etc/postgresql/12/main/pg_ident.conf
segment_size 131072 8kB
wal_block_size 8192
debug_assertions off
data_directory_mode 700
cluster_name pgsql
geqo_selection_bias 2
geqo_seed 0
geqo_effort 5
constraint_exclusion partition
cpu_tuple_cost 0.01
enable_mergejoin on
synchronous_standby_names
wal_keep_segments 8
max_wal_senders 5
wal_sender_timeout 60000 ms
max_replication_slots 5
max_standby_archive_delay 30000 ms
recovery_min_apply_delay 0 ms
vacuum_cost_page_miss 10
vacuum_cost_page_dirty 20
max_files_per_process 1000
log_planner_stats off
log_executor_stats off
track_counts on
stats_temp_directory pg_stat_tmp
array_nulls on
backslash_quote safe_encoding
operator_precedence_warning off
recovery_target_lsn
wal_log_hints on
wal_init_zero on