Добрый день.

Друзья, подскажите по механикам выделения памяти Постргесом. PG 12.3. Параметры виртуалки 4CPU, 8GB RAM. Много подключений, выполняющих короткие запросы, или в статусе Idle. Постоянно валятся ошибки Cannot allocate memory, Out of memory.
Что ему надо?

Конфиг Postgres
max_connections = 515
shared_buffers = 2048MB
huge_pages = try
work_mem = 32MB
dynamic_shared_memory_type = posix

$ free -m
total used free shared buff/cache available
Mem: 7821 1862 3649 241 2309 5638
Swap: 8191 0 8191

Лог

LOG: could not fork autovacuum worker process: Cannot allocate memory
HOST: DB: USER: LOG: could not fork new process for connection: Cannot allocate memory
PID:7567 HOST:192.168.0.12 DB:postgres USER:postgres FATAL: out of memory
LOG: could not fork autovacuum worker process: Cannot allocate memory
TopMemoryContext: 305968 total in 11 blocks; 42424 free (15 chunks); 263544 used
smgr relation table: 16384 total in 2 blocks; 4600 free (2 chunks); 11784 used
pgstat TabStatusArray lookup hash table: 8192 total in 1 blocks; 1456 free (0 chunks); 6736 used
TopTransactionContext: 8192 total in 1 blocks; 6656 free (10 chunks); 1536 used
TransactionAbortContext: 32768 total in 1 blocks; 32512 free (0 chunks); 256 used
Portal hash: 8192 total in 1 blocks; 560 free (0 chunks); 7632 used
TopPortalContext: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
Relcache by OID: 16384 total in 2 blocks; 7672 free (2 chunks); 8712 used
CacheMemoryContext: 262144 total in 6 blocks; 280 free (3 chunks); 261864 used
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_foreign_table_relid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_type_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_aggregate_fnoid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_constraint_oid_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_rewrite_rel_rulename_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_ts_parser_prsname_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_ts_config_cfgname_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_ts_parser_oid_index
index info: 2048 total in 2 blocks; 728 free (1 chunks); 1320 used: pg_publication_rel_prrelid_prpubid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_operator_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_namespace_nspname_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_ts_template_oid_index
index info: 2048 total in 2 blocks; 704 free (3 chunks); 1344 used: pg_amop_opr_fam_index
index info: 2048 total in 2 blocks; 672 free (3 chunks); 1376 used: pg_default_acl_role_nsp_obj_index
index info: 2048 total in 2 blocks; 704 free (3 chunks); 1344 used: pg_collation_name_enc_nsp_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_publication_rel_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_range_rngtypid_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_ts_dict_dictname_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_type_typname_nsp_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_opfamily_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_statistic_ext_oid_index
index info: 1024 total in 1 blocks; 16 free (0 chunks); 1008 used: pg_statistic_ext_data_stxoid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_class_oid_index
index info: 2048 total in 2 blocks; 704 free (3 chunks); 1344 used: pg_proc_proname_args_nsp_index
index info: 1024 total in 1 blocks; 16 free (0 chunks); 1008 used: pg_partitioned_table_partrelid_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_transform_type_lang_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_attribute_relid_attnum_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_proc_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_language_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_namespace_oid_index
index info: 3072 total in 2 blocks; 1216 free (3 chunks); 1856 used: pg_amproc_fam_proc_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_foreign_server_name_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_attribute_relid_attnam_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_conversion_oid_index
index info: 2048 total in 2 blocks; 728 free (1 chunks); 1320 used: pg_user_mapping_user_server_index
index info: 2048 total in 2 blocks; 728 free (1 chunks); 1320 used: pg_subscription_rel_srrelid_srsubid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_sequence_seqrelid_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_conversion_name_nsp_index
index info: 2048 total in 2 blocks; 952 free (1 chunks); 1096 used: pg_authid_oid_index
index info: 2048 total in 2 blocks; 648 free (1 chunks); 1400 used: pg_auth_members_member_role_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_subscription_oid_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_tablespace_oid_index
index info: 2048 total in 2 blocks; 704 free (3 chunks); 1344 used: pg_shseclabel_object_index
index info: 1024 total in 1 blocks; 16 free (0 chunks); 1008 used: pg_replication_origin_roname_index
index info: 2048 total in 2 blocks; 952 free (1 chunks); 1096 used: pg_database_datname_index
index info: 2048 total in 2 blocks; 760 free (2 chunks); 1288 used: pg_subscription_subname_index
index info: 1024 total in 1 blocks; 16 free (0 chunks); 1008 used: pg_replication_origin_roiident_index
index info: 2048 total in 2 blocks; 728 free (1 chunks); 1320 used: pg_auth_members_role_member_index
index info: 1024 total in 1 blocks; 48 free (0 chunks); 976 used: pg_database_oid_index
index info: 2048 total in 2 blocks; 952 free (1 chunks); 1096 used: pg_authid_rolname_index
WAL record construction: 49768 total in 2 blocks; 6368 free (0 chunks); 43400 used
PrivateRefCount: 8192 total in 1 blocks; 2624 free (0 chunks); 5568 used
MdSmgr: 8192 total in 1 blocks; 7936 free (0 chunks); 256 used
LOCALLOCK hash: 8192 total in 1 blocks; 560 free (0 chunks); 7632 used
Timezones: 104120 total in 2 blocks; 2624 free (0 chunks); 101496 used
Postmaster: 16384 total in 2 blocks; 15240 free (12 chunks); 1144 used
ident parser context: 1024 total in 1 blocks; 768 free (0 chunks); 256 used
hba parser context: 17408 total in 5 blocks; 3720 free (5 chunks); 13688 used
ErrorContext: 8192 total in 1 blocks; 7936 free (5 chunks); 256 used
Grand total: 964688 bytes in 116 blocks; 171712 free (100 chunks); 792976 used
PID:7573 HOST:192.168.0.12 DB:postgres USER:postgres FATAL: out of memory
PID:7573 HOST:192.168.0.12 DB:postgres USER:postgres DETAIL: Failed on request of size 140 in memory context "CacheMemoryContext".

pg000, пусто

Guzya,

Guzya, на сервере кроме СУБД больше ничего не установлено. ОС Ubuntu. В сторону пула для соединений движемся, но пока использовать его возможности нет. Я знаю, что PG плохо работает с большим количеством соединений.

Maxim Boguk,

Про СУБД на калькуляторе понятно. И тем не менее, почему он swap не использует? Вот пример с другого сервера.
267 cсесиий Idle.

Guzya,
спасибо, это оно.