1. Pg System Catalogs
- PostgreSQL store the metadata information about the database and cluster in the schema 'pg_catalog'.
- PostgreSQL manages system catalogs by itself.
| Name | Description |
| pg_database | Stores general database info |
| pg_stat_database | Contains stats information of database |
| pg_tablespace | Contains Tablespace information |
| pg_operator | Contains all operator information |
| pg_available_extensions | List all available extensions |
2. Examples
C:\Users\Maxwell Pan>
C:\Users\Maxwell Pan>psql -U postgres
Password for user postgres:
psql (15.2)
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
Type "help" for help.
postgres=# select * from pg_database;
oid | datname | datdba | encoding | datlocprovider | datistemplate | datallowconn | datconnlimit | datfrozenxid | datminmxid | dattablespace | datcollate | datctype | daticulocale | datcollversion | datacl
-------+-----------+--------+----------+----------------+---------------+--------------+--------------+--------------+------------+---------------+----------------------------+----------------------------+--------------+----------------+-----------------------------------------------------
5 | postgres | 10 | 6 | c | f | t | -1 | 717 | 1 | 1663 | English_United States.1252 | English_United States.1252 | | |
1 | template1 | 10 | 6 | c | t | t | -1 | 717 | 1 | 1663 | English_United States.1252 | English_United States.1252 | | | {=c/postgres,postgres=CTc/postgres}
4 | template0 | 10 | 6 | c | t | f | -1 | 717 | 1 | 1663 | English_United States.1252 | English_United States.1252 | | | {=c/postgres,postgres=CTc/postgres}
24602 | nano | 10 | 6 | c | f | t | -1 | 717 | 1 | 1663 | English_United States.1252 | English_United States.1252 | | | {=Tc/postgres,postgres=CTc/postgres,ron=c/postgres}
(4 rows)
postgres=# select * from pg_stat_database;
datid | datname | numbackends | xact_commit | xact_rollback | blks_read | blks_hit | tup_returned | tup_fetched | tup_inserted | tup_updated | tup_deleted | conflicts | temp_files | temp_bytes | deadlocks | checksum_failures | checksum_last_failure | blk_read_time | blk_write_time | session_time | active_time | idle_in_transaction_time | sessions | sessions_abandoned | sessions_fatal | sessions_killed | stats_reset
-------+-----------+-------------+-------------+---------------+-----------+----------+--------------+-------------+--------------+-------------+-------------+-----------+------------+------------+-----------+-------------------+-----------------------+---------------+----------------+-------------------+-------------+--------------------------+----------+--------------------+----------------+-----------------+-------------
0 | | 0 | 0 | 61 | 33 | 7231 | 2252 | 1769 | 12 | 2 | 6 | 0 | 0 | 0 | 0 | | | 0 | 0 | 44877637030378.56 | 0 | 0 | 0 | 0 | 0 | 0 |
5 | postgres | 1 | 352 | 15 | 315 | 38978 | 149811 | 14699 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | | 0 | 0 | 4107592.457 | 3152.605 | 0 | 23 | 0 | 0 | 0 |
1 | template1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
4 | template0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
24602 | nano | 0 | 333 | 8 | 218 | 15965 | 129131 | 4634 | 58 | 4 | 28 | 0 | 0 | 0 | 0 | | | 0 | 0 | 1814961.106 | 2322.586 | 0 | 15 | 0 | 0 | 0 |
(5 rows)
postgres=# select * from pg_tablespace;
oid | spcname | spcowner | spcacl | spcoptions
------+------------+----------+--------+------------
1663 | pg_default | 10 | |
1664 | pg_global | 10 | |
(2 rows)
postgres=# select * from pg_operator;
oid | oprname | oprnamespace | oprowner | oprkind | oprcanmerge | oprcanhash | oprleft | oprright | oprresult | oprcom | oprnegate | oprcode | oprrest | oprjoin
------+---------+--------------+----------+---------+-------------+------------+---------+----------+-----------+--------+-----------+------------------------------------+---------------+------------------
15 | = | 11 | 10 | b | t | t | 23 | 20 | 16 | 416 | 36 | int48eq | eqsel | eqjoinsel
36 | <> | 11 | 10 | b | f | f | 23 | 20 | 16 | 417 | 15 | int48ne | neqsel | neqjoinsel
37 | < | 11 | 10 | b | f | f | 23 | 20 | 16 | 419 | 82 | int48lt | scalarltsel | scalarltjoinsel
76 | > | 11 | 10 | b | f | f | 23 | 20 | 16 | 418 | 80 | int48gt | scalargtsel | scalargtjoinsel
80 | <= | 11 | 10 | b | f | f | 23 | 20 | 16 | 430 | 76 | int48le | scalarlesel | scalarlejoinsel
82 | >= | 11 | 10 | b | f | f | 23 | 20 | 16 | 420 | 37 | int48ge | scalargesel | scalargejoinsel
58 | < | 11 | 10 | b | f | f | 16 | 16 | 16 | 59 | 1695 | boollt | scalarltsel | scalarltjoinsel
59 | > | 11 | 10 | b | f | f | 16 | 16 | 16 | 58 | 1694 | boolgt | scalargtsel | scalargtjoinsel
85 | <> | 11 | 10 | b | f | f | 16 | 16 | 16 | 85 | 91 | boolne | neqsel | neqjoinsel
91 | = | 11 | 10 | b | t | t | 16 | 16 | 16 | 91 | 85 | booleq | eqsel | eqjoinsel
1694 | <= | 11 | 10 | b | f | f | 16 | 16 | 16 | 1695 | 59 | boolle | scalarlesel | scalarlejoinsel
1695 | >= | 11 | 10 | b | f | f | 16 | 16 | 16 | 1694 | 58 | boolge | scalargesel | scalargejoinsel
92 | = | 11 | 10 | b | t | t | 18 | 18 | 16 | 92 | 630 | chareq | eqsel | eqjoinsel
93 | = | 11 | 10 | b | t | t | 19 | 19 | 16 | 93 | 643 | nameeq | eqsel | eqjoinsel
94 | = | 11 | 10 | b | t | t | 21 | 21 | 16 | 94 | 519 | int2eq | eqsel | eqjoinsel
95 | < | 11 | 10 | b | f | f | 21 | 21 | 16 | 520 | 524 | int2lt | scalarltsel | scalarltjoinsel
96 | = | 11 | 10 | b | t | t | 23 | 23 | 16 | 96 | 518 | int4eq | eqsel | eqjoinsel
97 | < | 11 | 10 | b | f | f | 23 | 23 | 16 | 521 | 525 | int4lt | scalarltsel | scalarltjoinsel
98 | = | 11 | 10 | b | t | t | 25 | 25 | 16 | 98 | 531 | texteq | eqsel | eqjoinsel
3877 | ^@ | 11 | 10 | b | f | f | 25 | 25 | 16 | 0 | 0 | starts_with | prefixsel | prefixjoinsel
254 | = | 11 | 10 | b | t | t | 19 | 25 | 16 | 260 | 259 | nameeqtext | eqsel | eqjoinsel
255 | < | 11 | 10 | b | f | f | 19 | 25 | 16 | 264 | 257 | namelttext | scalarltsel | scalarltjoinsel
256 | <= | 11 | 10 | b | f | f | 19 | 25 | 16 | 263 | 258 | nameletext | scalarlesel | scalarlejoinsel
257 | >= | 11 | 10 | b | f | f | 19 | 25 | 16 | 262 | 255 | namegetext | scalargesel | scalargejoinsel
258 | > | 11 | 10 | b | f | f | 19 | 25 | 16 | 261 | 256 | namegttext | scalargtsel | scalargtjoinsel
259 | <> | 11 | 10 | b | f | f | 19 | 25 | 16 | 265 | 254 | namenetext | neqsel | neqjoinsel
260 | = | 11 | 10 | b | t | t | 25 | 19 | 16 | 254 | 265 | texteqname | eqsel | eqjoinsel
261 | < | 11 | 10 | b | f | f | 25 | 19 | 16 | 258 | 263 | textltname | scalarltsel | scalarltjoinsel
262 | <= | 11 | 10 | b | f | f | 25 | 19 | 16 | 257 | 264 | textlename | scalarlesel | scalarlejoinsel
263 | >= | 11 | 10 | b | f | f | 25 | 19 | 16 | 256 | 261 | textgename | scalargesel | scalargejoinsel
264 | > | 11 | 10 | b | f | f | 25 | 19 | 16 | 255 | 262 | textgtname | scalargtsel | scalargtjoinsel
265 | <> | 11 | 10 | b | f | f | 25 | 19 | 16 | 259 | 260 | textnename | neqsel | neqjoinsel
349 | || | 11 | 10 | b | f | f | 5078 | 5077 | 5078 | 0 | 0 | array_append | - | -
374 | || | 11 | 10 | b | f | f | 5077 | 5078 | 5078 | 0 | 0 | array_prepend | - | -
375 | || | 11 | 10 | b | f | f | 5078 | 5078 | 5078 | 0 | 0 | array_cat | - | -
352 | = | 11 | 10 | b | f | t | 28 | 28 | 16 | 352 | 3315 | xideq | eqsel | eqjoinsel
353 | = | 11 | 10 | b | f | f | 28 | 23 | 16 | 0 | 3316 | xideqint4 | eqsel | eqjoinsel
3315 | <> | 11 | 10 | b | f | f | 28 | 28 | 16 | 3315 | 352 | xidneq | neqsel | neqjoinsel
3316 | <> | 11 | 10 | b | f | f | 28 | 23 | 16 | 0 | 353 | xidneqint4 | neqsel | neqjoinsel
5068 | = | 11 | 10 | b | t | t | 5069 | 5069 | 16 | 5068 | 5072 | xid8eq | eqsel | eqjoinsel
5072 | <> | 11 | 10 | b | f | f | 5069 | 5069 | 16 | 5072 | 5068 | xid8ne | neqsel | neqjoinsel
5073 | < | 11 | 10 | b | f | f | 5069 | 5069 | 16 | 5074 | 5076 | xid8lt | scalarltsel | scalarltjoinsel
5074 | > | 11 | 10 | b | f | f | 5069 | 5069 | 16 | 5073 | 5075 | xid8gt | scalargtsel | scalargtjoinsel
5075 | <= | 11 | 10 | b | f | f | 5069 | 5069 | 16 | 5076 | 5074 | xid8le | scalarlesel | scalarlejoinsel
5076 | >= | 11 | 10 | b | f | f | 5069 | 5069 | 16 | 5075 | 5073 | xid8ge | scalargesel | scalargejoinsel
385 | = | 11 | 10 | b | f | t | 29 | 29 | 16 | 385 | 0 | cideq | eqsel | eqjoinsel
387 | = | 11 | 10 | b | t | t | 27 | 27 | 16 | 387 | 402 | tideq | eqsel | eqjoinsel
402 | <> | 11 | 10 | b | f | f | 27 | 27 | 16 | 402 | 387 | tidne | neqsel | neqjoinsel
2799 | < | 11 | 10 | b | f | f | 27 | 27 | 16 | 2800 | 2802 | tidlt | scalarltsel | scalarltjoinsel
2800 | > | 11 | 10 | b | f | f | 27 | 27 | 16 | 2799 | 2801 | tidgt | scalargtsel | scalargtjoinsel
2801 | <= | 11 | 10 | b | f | f | 27 | 27 | 16 | 2802 | 2800 | tidle | scalarlesel | scalarlejoinsel
2802 | >= | 11 | 10 | b | f | f | 27 | 27 | 16 | 2801 | 2799 | tidge | scalargesel | scalargejoinsel
410 | = | 11 | 10 | b | t | t | 20 | 20 | 16 | 410 | 411 | int8eq | eqsel | eqjoinsel
411 | <> | 11 | 10 | b | f | f | 20 | 20 | 16 | 411 | 410 | int8ne | neqsel | neqjoinsel
412 | < | 11 | 10 | b | f | f | 20 | 20 | 16 | 413 | 415 | int8lt | scalarltsel | scalarltjoinsel
413 | > | 11 | 10 | b | f | f | 20 | 20 | 16 | 412 | 414 | int8gt | scalargtsel | scalargtjoinsel
414 | <= | 11 | 10 | b | f | f | 20 | 20 | 16 | 415 | 413 | int8le | scalarlesel | scalarlejoinsel
415 | >= | 11 | 10 | b | f | f | 20 | 20 | 16 | 414 | 412 | int8ge | scalargesel | scalargejoinsel
416 | = | 11 | 10 | b | t | t | 20 | 23 | 16 | 15 | 417 | int84eq | eqsel | eqjoinsel
417 | <> | 11 | 10 | b | f | f | 20 | 23 | 16 | 36 | 416 | int84ne | neqsel | neqjoinsel
418 | < | 11 | 10 | b | f | f | 20 | 23 | 16 | 76 | 430 | int84lt | scalarltsel | scalarltjoinsel
419 | > | 11 | 10 | b | f | f | 20 | 23 | 16 | 37 | 420 | int84gt | scalargtsel | scalargtjoinsel
420 | <= | 11 | 10 | b | f | f | 20 | 23 | 16 | 82 | 419 | int84le | scalarlesel | scalarlejoinsel
^CCancel request sent
postgres=#
C:\Users\Maxwell Pan>pg_ctl status
pg_ctl: no server running
C:\Users\Maxwell Pan>pg_ctl start
waiting for server to start....2023-04-25 11:14:13.053 CST [18480] LOG: redirecting log output to logging collector process
2023-04-25 11:14:13.053 CST [18480] HINT: Future log output will appear in directory "log".
done
server started
C:\Users\Maxwell Pan>psql -U postgres
Password for user postgres:
psql (15.2)
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
Type "help" for help.
postgres=#
postgres=# select * from pg_shadow;
usename | usesysid | usecreatedb | usesuper | userepl | usebypassrls | passwd | valuntil | useconfig
----------+----------+-------------+----------+---------+--------------+---------------------------------------------------------------------------------------------------------------------------------------+----------+-----------
postgres | 10 | t | t | t | t | SCRAM-SHA-256$4096:BsDkIbrb3e4lL2bBCKcIbQ==$yWewHz+ULWqS9xQ5W3TqomcYotcKBAD336pvH49UyD4=:pyeJzwmbkoZm+OPQL00FjIAJBjIfDz3ezDIyxKf/rU4= | |
scott | 24582 | f | t | f | f | SCRAM-SHA-256$4096:64U6TqdG6RXDfdexWkhcpg==$ZSPC0F/0fQ5RSNv3W0b4JHIB5TlzbJyiBx6EJyiWkkk=:xJBm0R3A/4QR8jHuxL+IUjOoeYer/XI5D7n56mA1VXY= | |
sam | 24601 | t | f | f | f | SCRAM-SHA-256$4096:7AmjizcS4uCraRXSVGjFsg==$9fPB5r0mitAcovh11q+VKYmSTo9wDJRuSkjw4jocxKM=:Xm+mODf5X872X77IcfOrihFh2ozVnTptnNO+bpaVnnM= | |
ronk | 32772 | f | f | f | f | SCRAM-SHA-256$4096:jaHP7s41pulrAbEcKfaUdA==$/Ex3pDDQu7Vc9kqN0YOiUO/ZMnHXnct+3ap3MXMz9ng=:Cf7w7JHZ1YbmV0NEnZzz5NK16Lj5FU/5s62FHMZSqxk= | |
ron | 24599 | f | f | f | f | | |
(5 rows)
postgres=# \du
List of roles
Role name | Attributes | Member of
-----------+------------------------------------------------------------+-----------
postgres | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
ron | | {}
ronk | | {}
sam | Create DB | {}
scott | Superuser | {}
postgres=# select * from pg_timezone_names;
name | abbrev | utc_offset | is_dst
----------------------------------+--------+------------+--------
Africa/Abidjan | GMT | 00:00:00 | f
Africa/Accra | GMT | 00:00:00 | f
Africa/Addis_Ababa | EAT | 03:00:00 | f
Africa/Algiers | CET | 01:00:00 | f
Africa/Asmara | EAT | 03:00:00 | f
Africa/Asmera | EAT | 03:00:00 | f
Africa/Bamako | GMT | 00:00:00 | f
Africa/Bangui | WAT | 01:00:00 | f
Africa/Banjul | GMT | 00:00:00 | f
Africa/Bissau | GMT | 00:00:00 | f
Africa/Blantyre | CAT | 02:00:00 | f
Africa/Brazzaville | WAT | 01:00:00 | f
Africa/Bujumbura | CAT | 02:00:00 | f
Africa/Cairo | EET | 02:00:00 | f
Africa/Casablanca | +00 | 00:00:00 | t
Africa/Ceuta | CEST | 02:00:00 | t
Africa/Conakry | GMT | 00:00:00 | f
Africa/Dakar | GMT | 00:00:00 | f
Africa/Dar_es_Salaam | EAT | 03:00:00 | f
Africa/Djibouti | EAT | 03:00:00 | f
Africa/Douala | WAT | 01:00:00 | f
Africa/El_Aaiun | +00 | 00:00:00 | t
Africa/Freetown | GMT | 00:00:00 | f
Africa/Gaborone | CAT | 02:00:00 | f
Africa/Harare | CAT | 02:00:00 | f
Africa/Johannesburg | SAST | 02:00:00 | f
Africa/Juba | CAT | 02:00:00 | f
Africa/Kampala | EAT | 03:00:00 | f
Africa/Khartoum | CAT | 02:00:00 | f
Africa/Kigali | CAT | 02:00:00 | f
Africa/Kinshasa | WAT | 01:00:00 | f
Africa/Lagos | WAT | 01:00:00 | f
Africa/Libreville | WAT | 01:00:00 | f
Africa/Lome | GMT | 00:00:00 | f
Africa/Luanda | WAT | 01:00:00 | f
Africa/Lubumbashi | CAT | 02:00:00 | f
Africa/Lusaka | CAT | 02:00:00 | f
Africa/Malabo | WAT | 01:00:00 | f
Africa/Maputo | CAT | 02:00:00 | f
Africa/Maseru | SAST | 02:00:00 | f
Africa/Mbabane | SAST | 02:00:00 | f
Africa/Mogadishu | EAT | 03:00:00 | f
Africa/Monrovia | GMT | 00:00:00 | f
Africa/Nairobi | EAT | 03:00:00 | f
Africa/Ndjamena | WAT | 01:00:00 | f
Africa/Niamey | WAT | 01:00:00 | f
Africa/Nouakchott | GMT | 00:00:00 | f
Africa/Ouagadougou | GMT | 00:00:00 | f
Africa/Porto-Novo | WAT | 01:00:00 | f
Africa/Sao_Tome | GMT | 00:00:00 | f
Africa/Timbuktu | GMT | 00:00:00 | f
Africa/Tripoli | EET | 02:00:00 | f
Africa/Tunis | CET | 01:00:00 | f
Africa/Windhoek | CAT | 02:00:00 | f
America/Adak | HDT | -09:00:00 | t
America/Anchorage | AKDT | -08:00:00 | t
America/Anguilla | AST | -04:00:00 | f
America/Antigua | AST | -04:00:00 | f
America/Araguaina | -03 | -03:00:00 | f
America/Argentina/Buenos_Aires | -03 | -03:00:00 | f
America/Argentina/Catamarca | -03 | -03:00:00 | f
America/Argentina/ComodRivadavia | -03 | -03:00:00 | f
America/Argentina/Cordoba | -03 | -03:00:00 | f
^CCancel request sent
postgres=#
postgres=#
C:\Users\Maxwell Pan>psql -U postgres
Password for user postgres:
psql (15.2)
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
Type "help" for help.
postgres=# select * from pg_tables;
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | rowsecurity
--------------------+--------------------------+------------+------------+------------+----------+-------------+-------------
pg_catalog | pg_statistic | postgres | | t | f | f | f
pg_catalog | pg_type | postgres | | t | f | f | f
pg_catalog | pg_foreign_table | postgres | | t | f | f | f
pg_catalog | pg_authid | postgres | pg_global | t | f | f | f
pg_catalog | pg_statistic_ext_data | postgres | | t | f | f | f
pg_catalog | pg_user_mapping | postgres | | t | f | f | f
pg_catalog | pg_subscription | postgres | pg_global | t | f | f | f
pg_catalog | pg_attribute | postgres | | t | f | f | f
pg_catalog | pg_proc | postgres | | t | f | f | f
pg_catalog | pg_class | postgres | | t | f | f | f
pg_catalog | pg_attrdef | postgres | | t | f | f | f
pg_catalog | pg_constraint | postgres | | t | f | f | f
pg_catalog | pg_inherits | postgres | | t | f | f | f
pg_catalog | pg_index | postgres | | t | f | f | f
pg_catalog | pg_operator | postgres | | t | f | f | f
pg_catalog | pg_opfamily | postgres | | t | f | f | f
pg_catalog | pg_opclass | postgres | | t | f | f | f
pg_catalog | pg_am | postgres | | t | f | f | f
pg_catalog | pg_amop | postgres | | t | f | f | f
pg_catalog | pg_amproc | postgres | | t | f | f | f
pg_catalog | pg_language | postgres | | t | f | f | f
pg_catalog | pg_largeobject_metadata | postgres | | t | f | f | f
pg_catalog | pg_aggregate | postgres | | t | f | f | f
pg_catalog | pg_statistic_ext | postgres | | t | f | f | f
pg_catalog | pg_rewrite | postgres | | t | f | f | f
pg_catalog | pg_trigger | postgres | | t | f | f | f
pg_catalog | pg_event_trigger | postgres | | t | f | f | f
pg_catalog | pg_description | postgres | | t | f | f | f
pg_catalog | pg_cast | postgres | | t | f | f | f
pg_catalog | pg_enum | postgres | | t | f | f | f
pg_catalog | pg_namespace | postgres | | t | f | f | f
pg_catalog | pg_conversion | postgres | | t | f | f | f
pg_catalog | pg_depend | postgres | | t | f | f | f
pg_catalog | pg_database | postgres | pg_global | t | f | f | f
pg_catalog | pg_db_role_setting | postgres | pg_global | t | f | f | f
pg_catalog | pg_tablespace | postgres | pg_global | t | f | f | f
pg_catalog | pg_auth_members | postgres | pg_global | t | f | f | f
pg_catalog | pg_shdepend | postgres | pg_global | t | f | f | f
pg_catalog | pg_shdescription | postgres | pg_global | t | f | f | f
pg_catalog | pg_ts_config | postgres | | t | f | f | f
pg_catalog | pg_ts_config_map | postgres | | t | f | f | f
pg_catalog | pg_ts_dict | postgres | | t | f | f | f
pg_catalog | pg_ts_parser | postgres | | t | f | f | f
pg_catalog | pg_ts_template | postgres | | t | f | f | f
pg_catalog | pg_extension | postgres | | t | f | f | f
pg_catalog | pg_foreign_data_wrapper | postgres | | t | f | f | f
pg_catalog | pg_foreign_server | postgres | | t | f | f | f
pg_catalog | pg_policy | postgres | | t | f | f | f
pg_catalog | pg_replication_origin | postgres | pg_global | t | f | f | f
pg_catalog | pg_default_acl | postgres | | t | f | f | f
pg_catalog | pg_init_privs | postgres | | t | f | f | f
pg_catalog | pg_seclabel | postgres | | t | f | f | f
pg_catalog | pg_shseclabel | postgres | pg_global | t | f | f | f
pg_catalog | pg_collation | postgres | | t | f | f | f
pg_catalog | pg_parameter_acl | postgres | pg_global | t | f | f | f
pg_catalog | pg_partitioned_table | postgres | | t | f | f | f
pg_catalog | pg_range | postgres | | t | f | f | f
pg_catalog | pg_transform | postgres | | t | f | f | f
pg_catalog | pg_sequence | postgres | | t | f | f | f
pg_catalog | pg_publication | postgres | | t | f | f | f
pg_catalog | pg_publication_namespace | postgres | | t | f | f | f
pg_catalog | pg_publication_rel | postgres | | t | f | f | f
pg_catalog | pg_subscription_rel | postgres | | t | f | f | f
pg_catalog | pg_largeobject | postgres | | t | f | f | f
information_schema | sql_features | postgres | | f | f | f | f
information_schema | sql_implementation_info | postgres | | f | f | f | f
information_schema | sql_parts | postgres | | f | f | f | f
information_schema | sql_sizing | postgres | | f | f | f | f
(68 rows)
postgres=#
C:\Users\Maxwell Pan>psql -U postgres
Password for user postgres:
psql (15.2)
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
Type "help" for help.
postgres=# select * from pg_tables;
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | rowsecurity
--------------------+--------------------------+------------+------------+------------+----------+-------------+-------------
pg_catalog | pg_statistic | postgres | | t | f | f | f
pg_catalog | pg_type | postgres | | t | f | f | f
pg_catalog | pg_foreign_table | postgres | | t | f | f | f
pg_catalog | pg_authid | postgres | pg_global | t | f | f | f
pg_catalog | pg_statistic_ext_data | postgres | | t | f | f | f
pg_catalog | pg_user_mapping | postgres | | t | f | f | f
pg_catalog | pg_subscription | postgres | pg_global | t | f | f | f
pg_catalog | pg_attribute | postgres | | t | f | f | f
pg_catalog | pg_proc | postgres | | t | f | f | f
pg_catalog | pg_class | postgres | | t | f | f | f
pg_catalog | pg_attrdef | postgres | | t | f | f | f
pg_catalog | pg_constraint | postgres | | t | f | f | f
pg_catalog | pg_inherits | postgres | | t | f | f | f
pg_catalog | pg_index | postgres | | t | f | f | f
pg_catalog | pg_operator | postgres | | t | f | f | f
pg_catalog | pg_opfamily | postgres | | t | f | f | f
pg_catalog | pg_opclass | postgres | | t | f | f | f
pg_catalog | pg_am | postgres | | t | f | f | f
pg_catalog | pg_amop | postgres | | t | f | f | f
pg_catalog | pg_amproc | postgres | | t | f | f | f
pg_catalog | pg_language | postgres | | t | f | f | f
pg_catalog | pg_largeobject_metadata | postgres | | t | f | f | f
pg_catalog | pg_aggregate | postgres | | t | f | f | f
pg_catalog | pg_statistic_ext | postgres | | t | f | f | f
pg_catalog | pg_rewrite | postgres | | t | f | f | f
pg_catalog | pg_trigger | postgres | | t | f | f | f
pg_catalog | pg_event_trigger | postgres | | t | f | f | f
pg_catalog | pg_description | postgres | | t | f | f | f
pg_catalog | pg_cast | postgres | | t | f | f | f
pg_catalog | pg_enum | postgres | | t | f | f | f
pg_catalog | pg_namespace | postgres | | t | f | f | f
pg_catalog | pg_conversion | postgres | | t | f | f | f
pg_catalog | pg_depend | postgres | | t | f | f | f
pg_catalog | pg_database | postgres | pg_global | t | f | f | f
pg_catalog | pg_db_role_setting | postgres | pg_global | t | f | f | f
pg_catalog | pg_tablespace | postgres | pg_global | t | f | f | f
pg_catalog | pg_auth_members | postgres | pg_global | t | f | f | f
pg_catalog | pg_shdepend | postgres | pg_global | t | f | f | f
pg_catalog | pg_shdescription | postgres | pg_global | t | f | f | f
pg_catalog | pg_ts_config | postgres | | t | f | f | f
pg_catalog | pg_ts_config_map | postgres | | t | f | f | f
pg_catalog | pg_ts_dict | postgres | | t | f | f | f
pg_catalog | pg_ts_parser | postgres | | t | f | f | f
pg_catalog | pg_ts_template | postgres | | t | f | f | f
pg_catalog | pg_extension | postgres | | t | f | f | f
pg_catalog | pg_foreign_data_wrapper | postgres | | t | f | f | f
pg_catalog | pg_foreign_server | postgres | | t | f | f | f
pg_catalog | pg_policy | postgres | | t | f | f | f
pg_catalog | pg_replication_origin | postgres | pg_global | t | f | f | f
pg_catalog | pg_default_acl | postgres | | t | f | f | f
pg_catalog | pg_init_privs | postgres | | t | f | f | f
pg_catalog | pg_seclabel | postgres | | t | f | f | f
pg_catalog | pg_shseclabel | postgres | pg_global | t | f | f | f
pg_catalog | pg_collation | postgres | | t | f | f | f
pg_catalog | pg_parameter_acl | postgres | pg_global | t | f | f | f
pg_catalog | pg_partitioned_table | postgres | | t | f | f | f
pg_catalog | pg_range | postgres | | t | f | f | f
pg_catalog | pg_transform | postgres | | t | f | f | f
pg_catalog | pg_sequence | postgres | | t | f | f | f
pg_catalog | pg_publication | postgres | | t | f | f | f
pg_catalog | pg_publication_namespace | postgres | | t | f | f | f
pg_catalog | pg_publication_rel | postgres | | t | f | f | f
pg_catalog | pg_subscription_rel | postgres | | t | f | f | f
pg_catalog | pg_largeobject | postgres | | t | f | f | f
information_schema | sql_features | postgres | | f | f | f | f
information_schema | sql_implementation_info | postgres | | f | f | f | f
information_schema | sql_parts | postgres | | f | f | f | f
information_schema | sql_sizing | postgres | | f | f | f | f
(68 rows)
postgres=#
3. Working with Time Zones
postgres=#
postgres=# select current_schema();
current_schema
----------------
public
(1 row)
postgres=# select current_user;
current_user
--------------
postgres
(1 row)
postgres=# select current_database();
current_database
------------------
postgres
(1 row)
postgres=# select current_setting('max_parallel_workers');
current_setting
-----------------
8
(1 row)
postgres=# select current_setting('max_connections');
current_setting
-----------------
100
(1 row)
postgres=# select pg_postmaster_start_time();
pg_postmaster_start_time
-------------------------------
2023-04-25 11:21:56.904658+08
(1 row)
postgres=# select now() as current;
current
-------------------------------
2023-04-25 11:28:46.765431+08
(1 row)
postgres=# select (now() + interval '1 hour') as an_hour_later;
an_hour_later
------------------------------
2023-04-25 12:29:24.39778+08
(1 row)
postgres=# select (now() + interval '1 day') a_day_later;
a_day_later
------------------------------
2023-04-26 11:30:02.79809+08
(1 row)
postgres=# select now() - interval '2 hours 30 minutes' as deduct_time;
deduct_time
-------------------------------
2023-04-25 09:00:43.917592+08
(1 row)
postgres=#
