#目的
PostgreSQLのcontribモジュールをインストール
#コマンド
空き領域マップ（FreeSpaceMap）を確認する関数「pg_freespace」を利用するとエラー
→利用するためにはpg_freespacemapモジュールのインストールが必要
postgres=# select * from pg_freespace('t1');
ERROR: function pg_freespace(unknown) does not exist
行 1: select * from pg_freespace('t1');
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
create extension でモジュールをインストール
create extension モジュール名;
postgres=# create extension pg_freespacemap;
CREATE EXTENSION
再度pg_freespace関数を実行！
postgres=# select * from pg_freespace('t1');
blkno | avail
-------+-------
0 | 0
1 | 32
2 | 32
3 | 32
4 | 32
5 | 32
6 | 32
7 | 32
8 | 32
9 | 32
10 | 32
11 | 32
12 | 32
13 | 32
14 | 32
15 | 32
##インストールされているモジュールを確認
pg_available_extensions
postgres=# select * from pg_available_extensions;
name | default_version | installed_version | comment
---------------------+-----------------+-------------------+------------------------------------------------------------------------
adminpack | 2.1 | 2.1 | administrative functions for PostgreSQL
amcheck | 1.2 | | functions for verifying relation integrity
autoinc | 1.0 | | functions for autoincrementing fields
bloom | 1.0 | | bloom access method - signature file based index
bool_plperl | 1.0 | | transform between bool and plperl
bool_plperlu | 1.0 | | transform between bool and plperlu
btree_gin | 1.3 | | support for indexing common datatypes in GIN
btree_gist | 1.5 | | support for indexing common datatypes in GiST
citext | 1.6 | | data type for case-insensitive character strings
cube | 1.4 | | data type for multidimensional cubes
dblink | 1.2 | | connect to other PostgreSQL databases from within a database
dict_int | 1.0 | | text search dictionary template for integers
dict_xsyn | 1.0 | | text search dictionary template for extended synonym processing
dummy_index_am | 1.0 | | dummy_index_am - index access method template
earthdistance | 1.1 | | calculate great-circle distances on the surface of the Earth
file_fdw | 1.0 | | foreign-data wrapper for flat file access
hstore_plperl | 1.0 | | transform between hstore and plperl
hstore_plperlu | 1.0 | | transform between hstore and plperlu
hstore_plpython2u | 1.0 | | transform between hstore and plpython2u
hstore_plpython3u | 1.0 | | transform between hstore and plpython3u
hstore_plpythonu | 1.0 | | transform between hstore and plpythonu
insert_username | 1.0 | | functions for tracking who changed a table
intagg | 1.1 | | integer aggregator and enumerator (obsolete)
jsonb_plperl | 1.0 | | transform between jsonb and plperl
jsonb_plperlu | 1.0 | | transform between jsonb and plperlu
jsonb_plpython2u | 1.0 | | transform between jsonb and plpython2u
jsonb_plpython3u | 1.0 | | transform between jsonb and plpython3u
jsonb_plpythonu | 1.0 | | transform between jsonb and plpythonu
lo | 1.1 | | Large Object maintenance
ltree_plpython2u | 1.0 | | transform between ltree and plpython2u
ltree_plpython3u | 1.0 | | transform between ltree and plpython3u
ltree_plpythonu | 1.0 | | transform between ltree and plpythonu
moddatetime | 1.0 | | functions for tracking last modification time
pgcrypto | 1.3 | | cryptographic functions
pgrowlocks | 1.2 | | show row-level locking information
pgstattuple | 1.5 | | show tuple-level statistics
pg_buffercache | 1.3 | | examine the shared buffer cache
pg_freespacemap | 1.2 | 1.2 | examine the free space map (FSM)
pg_prewarm | 1.2 | | prewarm relation data
plperl | 1.0 | | PL/Perl procedural language
plperlu | 1.0 | | PL/PerlU untrusted procedural language
plpgsql | 1.0 | 1.0 | PL/pgSQL procedural language
plpython2u | 1.0 | | PL/Python2U untrusted procedural language
plpython3u | 1.0 | | PL/Python3U untrusted procedural language
plpythonu | 1.0 | | PL/PythonU untrusted procedural language
pltcl | 1.0 | | PL/Tcl procedural language
pltclu | 1.0 | | PL/TclU untrusted procedural language
sslinfo | 1.2 | | information about SSL certificates
system_stats | 1.0 | | EnterpriseDB system statistics for PostgreSQL
tcn | 1.0 | | Triggered change notifications
test_bloomfilter | 1.0 | | Test code for Bloom filter library
test_ext1 | 1.0 | | Test extension 1
test_ext2 | 1.0 | | Test extension 2
test_ext3 | 1.0 | | Test extension 3
test_ext4 | 1.0 | | Test extension 4
test_ext5 | 1.0 | | Test extension 5
test_ext6 | 1.0 | | test_ext6
test_ext7 | 1.0 | | Test extension 7
test_ext8 | 1.0 | | Test extension 8
test_ext_cyclic1 | 1.0 | | Test extension cyclic 1
test_ext_cyclic2 | 1.0 | | Test extension cyclic 2
test_ext_evttrig | 1.0 | | Test extension - event trigger
test_ginpostinglist | 1.0 | | Test code for ginpostinglist.c
test_integerset | 1.0 | | Test code for integerset
test_pg_dump | 1.0 | | Test pg_dump with an extension
test_predtest | 1.0 | | Test code for optimizer/util/predtest.c
test_rbtree | 1.0 | | Test code for red-black tree library
unaccent | 1.1 | | text search dictionary that removes accents
xml2 | 1.1 | | XPath querying and XSLT
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