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Code review for recent dbsize changes. Fix some thinkos, enforce coding

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style and message style standards, improve documentation.
This commit is contained in:
Tom Lane
2004-09-28 19:35:43 +00:00
parent 70c8fcb287
commit d9b68c8061
3 changed files with 98 additions and 94 deletions
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51
contrib/dbsize/README.dbsize
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@ -5,8 +5,8 @@ database object:
int8 relation_size(text)
int8 pg_database_size(oid)
int8 pg_tablespace_size(oid)
int8 pg_relation_size(oid)
int8 pg_tablespace_size(oid)
text pg_size_pretty(int8)
@ -15,40 +15,37 @@ The first two functions:
SELECT database_size('template1');
SELECT relation_size('pg_class');
take the name of the object, and support databases and tables. Please
note that relation_size() only reports table file usage and not the
space used by indexes and toast tables.
Functions using oids are:
take the name of the object (possibly schema-qualified, for relation_size),
while these functions take object OIDs:
SELECT pg_database_size(1); -- template1 database
SELECT pg_tablespace_size(1663); -- pg_default tablespace
SELECT pg_relation_size(1259); -- pg_class table size
SELECT pg_tablespace_size(1663); -- pg_default tablespace
pg_relation_size() will report the size of the table, index and toast
table OIDs, but they must be requested individually. To obtain the total
size of a table including all helper files you'd have to do something
like:
Please note that relation_size and pg_relation_size report only the size of
the selected relation itself; any subsidiary indexes or toast tables are not
counted. To obtain the total size of a table including all helper files
you'd have to do something like:
XXX This query does not work, syntax error XXX
SELECT pg_relation_size(cl.oid) AS tablesize,
CASE WHEN reltoastrelid=0 THEN 0
ELSE pg_relation_size(reltoastrelid) END AS toastsize,
SUM(pg_relation_size(indexrelid)) AS indexsize,
pg_size_pretty(pg_relation_size(cl.oid)
+ pg_relation_size(reltoastrelid)
+ SUM(pg_relation_size(indexrelid))::int8)
AS totalsize
FROM pg_class cl
JOIN pg_index ON cl.oid=indrelid
WHERE relname = 'pg_rewrite'
GROUP BY 1,2
SELECT *,
pg_size_pretty(tablesize+indexsize+toastsize+toastindexsize) AS totalsize
FROM
(SELECT pg_relation_size(cl.oid) AS tablesize,
COALESCE((SELECT SUM(pg_relation_size(indexrelid))::bigint
FROM pg_index WHERE cl.oid=indrelid), 0) AS indexsize,
CASE WHEN reltoastrelid=0 THEN 0
ELSE pg_relation_size(reltoastrelid)
END AS toastsize,
CASE WHEN reltoastrelid=0 THEN 0
ELSE pg_relation_size((SELECT reltoastidxid FROM pg_class ct
WHERE ct.oid = cl.reltoastrelid))
END AS toastindexsize
FROM pg_class cl
WHERE relname = 'foo') ss;
This sample query utilizes the helper function pg_size_pretty(int8),
which formats the number of bytes into a convenient string using KB, MB,
GB. It is also contained in this module.
To install, just run make; make install. Finally, load the functions
To install, just run make; make install. Then load the functions
into any database using dbsize.sql.