Lu, Huayi
e6fa411af0
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com> Co-authored-by: Lu, Huayi <luhuayi@huawei.com> Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
14 KiB
Database Object Size Functions
Database object size functions calculate the actual disk space used by database objects.
pg_column_size(any)
Description: Specifies the number of bytes used to store a particular value (possibly compressed).
Return type: integer
Note: pg_column_size displays the space for storing an independent data value.
1 2 3 4 5 | SELECT pg_column_size(1); pg_column_size ---------------- 4 (1 row) |
pg_database_size(oid)
Description: Specifies the disk space used by the database with the specified OID.
Return type: bigint
pg_database_size(name)
Description: Specifies the disk space used by the database with the specified name.
Return type: bigint
Note: pg_database_size receives the OID or name of a database and returns the disk space used by the corresponding object.
Example:
1 2 3 4 5 | SELECT pg_database_size('gaussdb'); pg_database_size ------------------ 51590112 (1 row) |
pg_relation_size(oid)
Description: Specifies the disk space used by the table with a specified OID or index.
Return type: bigint
get_db_source_datasize()
Description: Estimates the total size of non-compressed data in the current database.
Return type: bigint
Note: (1) ANALYZE must be performed before this function is called. (2) Calculate the total size of non-compressed data by estimating the compression rate of column-store tables.
Example:
1 2 3 4 5 6 7 | analyze; ANALYZE SELECT get_db_source_datasize(); get_db_source_datasize ------------------------ 35384925667 (1 row) |
pg_relation_size(text)
Description: Specifies the disk space used by the table with a specified name or index. The table name can be schema-qualified.
Return type: bigint
pg_relation_size(relation regclass, fork text)
Description: Specifies the disk space used by the specified bifurcating tree ('main', 'fsm', or 'vm') of a certain table or index.
Return type: bigint
pg_relation_size(relation regclass)
Description: Is an abbreviation of pg_relation_size(..., 'main').
Return type: bigint
Note: pg_relation_size receives the OID or name of a table, index, or compressed table, and returns the size.
pg_partition_size(oid,oid)
Description: Specifies the disk space used by the partition with a specified OID. The first oid is the OID of the table and the second oid is the OID of the partition.
Return type: bigint
pg_partition_size(text, text)
Description: Specifies the disk space used by the partition with a specified name. The first text is the table name and the second text is the partition name.
Return type: bigint
pg_partition_indexes_size(oid,oid)
Description: Specifies the disk space used by the index of the partition with a specified OID. The first oid is the OID of the table and the second oid is the OID of the partition.
Return type: bigint
pg_partition_indexes_size(text,text)
Description: Specifies the disk space used by the index of the partition with a specified name. The first text is the table name and the second text is the partition name.
Return type: bigint
pg_indexes_size(regclass)
Description: Specifies the total disk space used by the index appended to the specified table.
Return type: bigint
pg_size_pretty(bigint)
Description: Converts the calculated byte size into a size readable to human beings.
Return type: text
pg_size_pretty(numeric)
Description: Converts the calculated byte size indicated by a numeral into a size readable to human beings.
Return type: text
Note: pg_size_pretty formats the results of other functions into a human-readable format. KB/MB/GB/TB can be used.
pg_table_size(regclass)
Description: Specifies the disk space used by the specified table, excluding indexes (but including TOAST, free space mapping, and visibility mapping).
Return type: bigint
pg_total_relation_size(oid)
Description: Specifies the disk space used by the table with a specified OID, including the index and the compressed data.
Return type: bigint
pg_total_relation_size(regclass)
Description: Specifies the total disk space used by the specified table, including all indexes and TOAST data.
Return type: bigint
pg_total_relation_size(text)
Description: Specifies the disk space used by the table with a specified name, including the index and the compressed data. The table name can be schema-qualified.
Return type: bigint
Note: pg_total_relation_size receives the OID or name of a table or a compressed table, and returns the sizes of the data, related indexes, and the compressed table in bytes.