[ADMIN] Repeating autovacuum

Hello,

I have a PostgreSQL 9.6.2 running on Windows 10 EnterpriseDB binaries. This
is a software development desktop computer having i7 entry level CPU and
Sandisk Extreme SSD and 8GB RAM.

While trying to figure some login related stuff, I realize that autovacuum
is repeating non-stop. Below is about 15-20 minute debug2 level log entries
after restarting the server.

I have 2 databases which have only table definitions in them. Only one of
them named "tracker" have about 15 records in it. Basically they are empty.

Memory related parameters in my config file are not modified, just removed
remarks on below items:
shared_buffers = 128M
work_mem = 4MB
maintenance_work_mem = 64MB
autovacuum_work_mem = -1

No autovacuum parameters are changed or used. They are all remarked as in
default config file.

I wonder if that is a normal behavior as system is idle.
-----
LOG:  database system was shut down at 2017-04-08 01:04:50 +03
DEBUG:  checkpoint record is at 0/17662D8
DEBUG:  redo record is at 0/17662D8; shutdown TRUE
DEBUG:  next transaction ID: 0:697; next OID: 16888
DEBUG:  next MultiXactId: 1; next MultiXactOffset: 0
DEBUG:  oldest unfrozen transaction ID: 536, in database 12401
DEBUG:  oldest MultiXactId: 1, in database 16526
DEBUG:  commit timestamp Xid oldest/newest: 0/0
DEBUG:  transaction ID wrap limit is 2147484183, limited by database with
OID 12401
DEBUG:  MultiXactId wrap limit is 2147483648, limited by database with OID
16526
DEBUG:  starting up replication slots
DEBUG:  MultiXactId wrap limit is 2147483648, limited by database with OID
16526
LOG:  MultiXact member wraparound protections are now enabled
DEBUG:  MultiXact member stop limit is now 4294914944 based on MultiXact 1
LOG:  database system is ready to accept connections
DEBUG:  checkpointer updated shared memory configuration values
LOG:  autovacuum launcher started
DEBUG:  removing permanent stats file "pg_stat/db_12401.stat"
DEBUG:  removing permanent stats file "pg_stat/db_1.stat"
DEBUG:  removing permanent stats file "pg_stat/db_16526.stat"
DEBUG:  removing permanent stats file "pg_stat/db_16461.stat"
DEBUG:  removing permanent stats file "pg_stat/db_0.stat"
DEBUG:  removing permanent stats file "pg_stat/global.stat"
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  forked new backend, pid=8716 socket=5016
LOG:  connection received: host=::1 port=60268
LOG:  connection authorized: user=DESKTOP-L63HSP2$ database=postgres
DEBUG:  server process (PID 8716) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "tracker"
DEBUG:  received inquiry for database 16526
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16526.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 14664) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "spanc"
DEBUG:  received inquiry for database 16461
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16461.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 16176) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "template1"
DEBUG:  received inquiry for database 1
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_1.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 16220) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "postgres"
DEBUG:  received inquiry for database 12401
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_12401.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 8568) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "tracker"
DEBUG:  received inquiry for database 16526
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16526.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 16156) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "spanc"
DEBUG:  received inquiry for database 16461
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16461.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 14892) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "template1"
DEBUG:  received inquiry for database 1
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_1.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 17756) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "postgres"
DEBUG:  received inquiry for database 12401
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_12401.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 18316) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "tracker"
DEBUG:  received inquiry for database 16526
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16526.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 14204) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "spanc"
DEBUG:  received inquiry for database 16461
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_16461.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 5668) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "template1"
DEBUG:  received inquiry for database 1
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_1.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 15884) exited with exit code 0
DEBUG:  received inquiry for database 0
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  autovacuum: processing database "postgres"
DEBUG:  received inquiry for database 12401
DEBUG:  writing stats file "pg_stat_tmp/global.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_12401.stat"
DEBUG:  writing stats file "pg_stat_tmp/db_0.stat"
DEBUG:  server process (PID 5188) exited with exit code 0
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