Table space grow big - PostgreSQL

Hi all

Please assist on this scenario, I am a junior DBA, perhaps the question I have is too simple please bear with me.

I have a server with one PostgreSQL database and the data reside in /usr/local/pgsql/data/ running on Redhat 9 O/S.

File system looks as follows:

Filesystem Size Used Avail Use% Mounted on
/dev/hda3 73G 61G 8.7G 88% /
/dev/hda1 99M 63M 32M 67% /boot
none 441M 0 441M 0% /dev/shm

Disc space utilization looks as follows where the data/ directory seems to be taking a lot of space compared to any other directories:

From / directory on user root/:

Size directory
4.0K ./lost+found
58M ./boot
436K ./dev
900M ./proc
1.1G ./var
263M ./tmp
25M ./etc
26M ./root
57G ./usr
5.3M ./bin
2.0G ./home
4.0K ./initrd
68M ./lib
32K ./mnt
4.0K ./opt
15M ./sbin
4.0K ./misc
4.0K ./.automount
48K ./tftpboot
44K ./backup
211M ./u
8.0K ./backups
62G . - Size

/usr/local/pgsql/data/base directory shows the following where 95186722/ takes a lot of space :

3.6M ./1
3.6M ./16975
51G ./95186722
4.8M ./4830693
51G .

Some files (which are called table space names, please correct me if I am wrong?) listed under 95186722/ directory shows different sizes where the biggest of all is 440M :

-rw------- 1 postgres postgres 16K May 5 12:50 219436402
-rw------- 1 postgres postgres 16K May 5 12:50 219436401
-rw------- 1 postgres postgres 16K May 5 12:50 219436400
-rw------- 1 postgres postgres 16K May 5 12:50 219436399
-rw------- 1 postgres postgres 34M May 5 12:50 219436274
-rw------- 1 postgres postgres 42M May 5 12:50 219436273
-rw------- 1 postgres postgres 43M May 5 12:50 219436272
-rw------- 1 postgres postgres 42M May 5 12:50 219436271
-rw------- 1 postgres postgres 34M May 5 12:50 219436270
-rw------- 1 postgres postgres 42M May 5 12:50 219436269
-rw------- 1 postgres postgres 42M May 5 12:50 219436268
-rw------- 1 postgres postgres 51M May 5 12:50 219436267
-rw------- 1 postgres postgres 34M May 5 12:50 219436266
-rw------- 1 postgres postgres 51M May 5 12:50 219436265
-rw------- 1 postgres postgres 15M May 5 12:50 218478745
-rw------- 1 postgres postgres 11M May 5 12:50 218478744
-rw------- 1 postgres postgres 10M May 5 12:50 218478743
-rw------- 1 postgres postgres 13M May 5 12:50 218478742
-rw------- 1 postgres postgres 440M May 5 12:50 216081969.1

Now the dump file of the very same database created by using command : pg_dump -U user -O dbname > /tmp/filename is 2.8G big. :

-rw-r--r-- 1 root root 2.8G May 5 12:47 db.dump

The main question I have is: What makes the /usr/local/pgsql/data/base/95186722/ grow so big while the actual data with its schema is only 2.8G and that is there a way to reduce the table space sizes or anything related to that?

Your response will be truly appreciated

Thanks
Khangelani Gama

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