postgresql/contrib/pgstattuple/expected/pgstattuple.out
Robert Haas 620b49a16d hash: Increase the number of possible overflow bitmaps by 8x.
Per a report from AP, it's not that hard to exhaust the supply of
bitmap pages if you create a table with a hash index and then insert a
few billion rows - and then you start getting errors when you try to
insert additional rows.  In the particular case reported by AP,
there's another fix that we can make to improve recycling of overflow
pages, which is another way to avoid the error, but there may be other
cases where this problem happens and that fix won't help.  So let's
buy ourselves as much headroom as we can without rearchitecting
anything.

The comments claim that the old limit was 64GB, but it was really
only 32GB, because we didn't use all the bits in the page for bitmap
bits - only the largest power of 2 that could fit after deducting
space for the page header and so forth.  Thus, we have 4kB per page
for bitmap bits, not 8kB.  The new limit is thus actually 8 times the
old *real* limit but only 4 times the old *purported* limit.

Since this breaks on-disk compatibility, bump HASH_VERSION.  We've
already done this earlier in this release cycle, so this doesn't cause
any incremental inconvenience for people using pg_upgrade from
releases prior to v10.  However, users who use pg_upgrade to reach
10beta3 or later from 10beta2 or earlier will need to REINDEX any hash
indexes again.

Amit Kapila and Robert Haas

Discussion: http://postgr.es/m/20170704105728.mwb72jebfmok2nm2@zip.com.au
2017-08-04 16:30:32 -04:00

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CREATE EXTENSION pgstattuple;
--
-- It's difficult to come up with platform-independent test cases for
-- the pgstattuple functions, but the results for empty tables and
-- indexes should be that.
--
create table test (a int primary key, b int[]);
select * from pgstattuple('test');
table_len | tuple_count | tuple_len | tuple_percent | dead_tuple_count | dead_tuple_len | dead_tuple_percent | free_space | free_percent
-----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
(1 row)
select * from pgstattuple('test'::text);
table_len | tuple_count | tuple_len | tuple_percent | dead_tuple_count | dead_tuple_len | dead_tuple_percent | free_space | free_percent
-----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
(1 row)
select * from pgstattuple('test'::name);
table_len | tuple_count | tuple_len | tuple_percent | dead_tuple_count | dead_tuple_len | dead_tuple_percent | free_space | free_percent
-----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
(1 row)
select * from pgstattuple('test'::regclass);
table_len | tuple_count | tuple_len | tuple_percent | dead_tuple_count | dead_tuple_len | dead_tuple_percent | free_space | free_percent
-----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
(1 row)
select pgstattuple(oid) from pg_class where relname = 'test';
pgstattuple
---------------------
(0,0,0,0,0,0,0,0,0)
(1 row)
select pgstattuple(relname) from pg_class where relname = 'test';
pgstattuple
---------------------
(0,0,0,0,0,0,0,0,0)
(1 row)
select version, tree_level,
index_size / current_setting('block_size')::int as index_size,
root_block_no, internal_pages, leaf_pages, empty_pages, deleted_pages,
avg_leaf_density, leaf_fragmentation
from pgstatindex('test_pkey');
version | tree_level | index_size | root_block_no | internal_pages | leaf_pages | empty_pages | deleted_pages | avg_leaf_density | leaf_fragmentation
---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | NaN | NaN
(1 row)
select version, tree_level,
index_size / current_setting('block_size')::int as index_size,
root_block_no, internal_pages, leaf_pages, empty_pages, deleted_pages,
avg_leaf_density, leaf_fragmentation
from pgstatindex('test_pkey'::text);
version | tree_level | index_size | root_block_no | internal_pages | leaf_pages | empty_pages | deleted_pages | avg_leaf_density | leaf_fragmentation
---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | NaN | NaN
(1 row)
select version, tree_level,
index_size / current_setting('block_size')::int as index_size,
root_block_no, internal_pages, leaf_pages, empty_pages, deleted_pages,
avg_leaf_density, leaf_fragmentation
from pgstatindex('test_pkey'::name);
version | tree_level | index_size | root_block_no | internal_pages | leaf_pages | empty_pages | deleted_pages | avg_leaf_density | leaf_fragmentation
---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | NaN | NaN
(1 row)
select version, tree_level,
index_size / current_setting('block_size')::int as index_size,
root_block_no, internal_pages, leaf_pages, empty_pages, deleted_pages,
avg_leaf_density, leaf_fragmentation
from pgstatindex('test_pkey'::regclass);
version | tree_level | index_size | root_block_no | internal_pages | leaf_pages | empty_pages | deleted_pages | avg_leaf_density | leaf_fragmentation
---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | NaN | NaN
(1 row)
select pg_relpages('test');
pg_relpages
-------------
0
(1 row)
select pg_relpages('test_pkey');
pg_relpages
-------------
1
(1 row)
select pg_relpages('test_pkey'::text);
pg_relpages
-------------
1
(1 row)
select pg_relpages('test_pkey'::name);
pg_relpages
-------------
1
(1 row)
select pg_relpages('test_pkey'::regclass);
pg_relpages
-------------
1
(1 row)
select pg_relpages(oid) from pg_class where relname = 'test_pkey';
pg_relpages
-------------
1
(1 row)
select pg_relpages(relname) from pg_class where relname = 'test_pkey';
pg_relpages
-------------
1
(1 row)
create index test_ginidx on test using gin (b);
select * from pgstatginindex('test_ginidx');
version | pending_pages | pending_tuples
---------+---------------+----------------
2 | 0 | 0
(1 row)
create index test_hashidx on test using hash (b);
select * from pgstathashindex('test_hashidx');
version | bucket_pages | overflow_pages | bitmap_pages | unused_pages | live_items | dead_items | free_percent
---------+--------------+----------------+--------------+--------------+------------+------------+--------------
4 | 4 | 0 | 1 | 0 | 0 | 0 | 100
(1 row)
-- these should error with the wrong type
select pgstatginindex('test_pkey');
ERROR: relation "test_pkey" is not a GIN index
select pgstathashindex('test_pkey');
ERROR: relation "test_pkey" is not a HASH index
select pgstatindex('test_ginidx');
ERROR: relation "test_ginidx" is not a btree index
select pgstathashindex('test_ginidx');
ERROR: relation "test_ginidx" is not a HASH index
select pgstatindex('test_hashidx');
ERROR: relation "test_hashidx" is not a btree index
select pgstatginindex('test_hashidx');
ERROR: relation "test_hashidx" is not a GIN index
-- check that using any of these functions with unsupported relations will fail
create table test_partitioned (a int) partition by range (a);
-- these should all fail
select pgstattuple('test_partitioned');
ERROR: "test_partitioned" (partitioned table) is not supported
select pgstattuple_approx('test_partitioned');
ERROR: "test_partitioned" is not a table or materialized view
select pg_relpages('test_partitioned');
ERROR: "test_partitioned" is not a table, index, materialized view, sequence, or TOAST table
select pgstatindex('test_partitioned');
ERROR: relation "test_partitioned" is not a btree index
select pgstatginindex('test_partitioned');
ERROR: relation "test_partitioned" is not a GIN index
select pgstathashindex('test_partitioned');
ERROR: "test_partitioned" is not an index
create view test_view as select 1;
-- these should all fail
select pgstattuple('test_view');
ERROR: "test_view" (view) is not supported
select pgstattuple_approx('test_view');
ERROR: "test_view" is not a table or materialized view
select pg_relpages('test_view');
ERROR: "test_view" is not a table, index, materialized view, sequence, or TOAST table
select pgstatindex('test_view');
ERROR: relation "test_view" is not a btree index
select pgstatginindex('test_view');
ERROR: relation "test_view" is not a GIN index
select pgstathashindex('test_view');
ERROR: "test_view" is not an index
create foreign data wrapper dummy;
create server dummy_server foreign data wrapper dummy;
create foreign table test_foreign_table () server dummy_server;
-- these should all fail
select pgstattuple('test_foreign_table');
ERROR: "test_foreign_table" (foreign table) is not supported
select pgstattuple_approx('test_foreign_table');
ERROR: "test_foreign_table" is not a table or materialized view
select pg_relpages('test_foreign_table');
ERROR: "test_foreign_table" is not a table, index, materialized view, sequence, or TOAST table
select pgstatindex('test_foreign_table');
ERROR: relation "test_foreign_table" is not a btree index
select pgstatginindex('test_foreign_table');
ERROR: relation "test_foreign_table" is not a GIN index
select pgstathashindex('test_foreign_table');
ERROR: "test_foreign_table" is not an index
-- a partition of a partitioned table should work though
create table test_partition partition of test_partitioned for values from (1) to (100);
select pgstattuple('test_partition');
pgstattuple
---------------------
(0,0,0,0,0,0,0,0,0)
(1 row)
select pgstattuple_approx('test_partition');
pgstattuple_approx
-----------------------
(0,0,0,0,0,0,0,0,0,0)
(1 row)
select pg_relpages('test_partition');
pg_relpages
-------------
0
(1 row)
-- not for the index calls though, of course
select pgstatindex('test_partition');
ERROR: relation "test_partition" is not a btree index
select pgstatginindex('test_partition');
ERROR: relation "test_partition" is not a GIN index
select pgstathashindex('test_partition');
ERROR: "test_partition" is not an index
-- an actual index of a partitioned table should work though
create index test_partition_idx on test_partition(a);
create index test_partition_hash_idx on test_partition using hash (a);
-- these should work
select pgstatindex('test_partition_idx');
pgstatindex
------------------------------
(2,0,8192,0,0,0,0,0,NaN,NaN)
(1 row)
select pgstathashindex('test_partition_hash_idx');
pgstathashindex
---------------------
(4,8,0,1,0,0,0,100)
(1 row)
drop table test_partitioned;
drop view test_view;
drop foreign table test_foreign_table;
drop server dummy_server;
drop foreign data wrapper dummy;