Gbase 8C database object size function (I)

The database object size function calculates the actual disk space used by the database object .

pg_column_size(any)

describe ： The number of bytes required to store a specified value （ May be compressed ）.

return type ：int

remarks ：pg_column_size Displays the space used to store an independent data value .

 gbase=# SELECT pg_column_size(1);

 pg_column_size

----------------

              4

(1 row)

pg_database_size(oid)

describe ： Appoint OID Represents the disk space used by the database .

return type ：bigint

pg_database_size(name)

describe ： Disk space used by the named database .

return type ：bigint

remarks ：pg_database_size Accept a database OID Or the name , Then return all the disk space used by the object .

Example ：

 gbase=# SELECT pg_database_size('postgres');

 pg_database_size

------------------

         30840684

(1 row)

pg_relation_size(oid)

describe ： Appoint OID Represents the disk space used by the table or index .

return type ：bigint

get_db_source_datasize()

describe ： Estimate the total capacity of uncompressed data in the current database .

return type ：bigint

remarks ：（1） Before calling this function analyze;（2） Calculate the total data capacity of the uncompressed state by estimating the compression ratio of the column storage .

Example ：

gbase=# analyze;

ANALYZE

gbase=# select get_db_source_datasize();

 get_db_source_datasize

------------------------

            31029100

(1 row)

pg_relation_size(text)

describe ： Specify the disk space used by the named table or index . Table names can be decorated with schema names .

return type ：bigint

pg_relation_size(relation regclass, fork text)

describe ： Specify the specified fork tree of the table or index （'main','fsm' or 'vm'） Disk space used .

return type ：bigint

pg_relation_size(relation regclass)

describe ：pg_relation_size(…, 'main') Abbreviation .

return type ：bigint

remarks ：pg_relation_size Accept a table 、 Indexes 、 Of compressed tables OID Or the name , Then return their byte size .