Extensions - PostgreSQL Developer's Guide - page 226

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directory
• pg_file_length : The pg_file_lenght function is used to get the length of
ile. This can be explained using the following example, in which we need
to recreate the ile as we just removed before using the pg_file_length
function:
warehouse_db=# SELECT pg_file_write('foo.txt', 'Hello
World', false);
pg_file_write
---------------
11
(1 row)
warehouse_db=# SELECT pg_file_length('foo.txt');
pg_file_length
----------------
11
(1 row)
• pg_logdir_ls : The pg_logdir_ls function lists all iles in a log directory
• pg_file_read : The user can read the data from the ile by making use of the
pg_file_read function
• pg_logfile_rotate : The user can rotate a log ile using the pg_logfile_
rotate function
The chkpass extension
This extension provides a new data type chkpass , which can be used to store
encrypted data. Most of the time, we need to store the data in a database that cannot be
read or stored or encrypted like passwords. Any values encrypted before saving into a
column shows that the data type is chkpass and cannot be read in clear text. Its value
can only be compared with string literals or non-encrypted values of the columns.
Creating the CHKPASS extension using the following statement:
warehouse_db=# CREATE EXTENSION CHKPASS;
Creating the foo table using the following statement:
warehouse_db=# CREATE TABLE foo (id INTEGER, username TEXT,
password CHKPASS);