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116 lines
3.7 KiB
Plaintext
116 lines
3.7 KiB
Plaintext
This module contains several functions that report the on-disk size of a
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given database object in bytes:
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int8 database_size(name)
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int8 relation_size(text)
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int8 indexes_size(text)
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int8 total_relation_size(text)
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int8 pg_database_size(oid)
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int8 pg_relation_size(oid)
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int8 pg_tablespace_size(oid)
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text pg_size_pretty(int8)
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setof record relation_size_components(text)
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The first four functions take the name of the object (possibly
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schema-qualified for the latter three) and returns the size of the
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on-disk files in bytes.
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SELECT database_size('template1');
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SELECT relation_size('pg_class');
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SELECT indexes_size('pg_class');
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SELECT total_relation_size('pg_class');
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These functions take object OIDs:
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SELECT pg_database_size(1); -- template1 database
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SELECT pg_relation_size(1259); -- pg_class table size
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SELECT pg_tablespace_size(1663); -- pg_default tablespace
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The indexes_size() function returns the total size of the indices for a
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relation, including any toasted indices.
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The total_relation_size() function returns the total size of the relation,
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all its indices, and any toasted data.
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Please note that relation_size and pg_relation_size report only the size of
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the selected relation itself; any related indexes or toast tables are not
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counted. To obtain the total size of a table including all indices and
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toasted data, use total_relation_size().
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The last function, relation_size_components(), returns a set of rows
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showing the sizes of the component relations constituting the input
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relation.
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Examples
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========
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I've loaded the following table with a little less than 3 MB of data for
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illustration:
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create table fat ( id serial, data varchar );
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create index fat_uidx on fat (id);
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create index fat_idx on fat (data);
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You can retrieve a rowset containing constituent sizes as follows:
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# SELECT relation_size_components('fat');
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relation_size_components
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----------------------------------------------------
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(2088960,65536,2891776,fat,r,59383,59383)
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(32768,704512,737280,pg_toast_59383,t,59386,59386)
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(0,32768,32768,pg_toast_59383_index,i,59388,59388)
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(0,2039808,2039808,fat_idx,i,59389,59389)
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(0,49152,49152,fat_uidx,i,59911,59911)
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(5 rows)
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To see a more readable output of the rowset:
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SELECT *
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FROM relation_size_components('fat') AS (idxsize BIGINT,
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datasize BIGINT,
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totalsize BIGINT,
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relname NAME,
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kind "char",
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relid OID,
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node OID)
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ORDER BY totalsize;
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idxsize | datasize | totalsize | relname | kind | relid | node
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---------+----------+-----------+----------------------+------+-------+-------
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0 | 32768 | 32768 | pg_toast_59383_index | i | 59388 | 59388
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0 | 49152 | 49152 | fat_uidx | i | 59911 | 59911
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32768 | 704512 | 737280 | pg_toast_59383 | t | 59386 | 59386
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0 | 2039808 | 2039808 | fat_idx | i | 59389 | 59389
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2088960 | 65536 | 2891776 | fat | r | 59383 | 59383
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(5 rows)
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To see the sum total size of a relation:
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# select total_relation_size('fat');
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total_relation_size
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-------------------------
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2891776
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(1 row)
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To see just the size of the uncompressed relation data:
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# select relation_size('fat');
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relation_size
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---------------
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65536
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(1 row)
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To see the size of all related indices:
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# select indexes_size('fat');
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indexes_size
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--------------
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2088960
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(1 row)
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To install, just run make; make install. Then load the functions
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into any database using dbsize.sql.
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