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Add pageinspect functions for inspecting GIN indexes.

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Patch by me, Peter Geoghegan and Michael Paquier, reviewed by Amit Kapila.
This commit is contained in:
Heikki Linnakangas
2014-11-21 11:46:50 +02:00
parent adbfab119b
commit 3a82bc6f8a
5 changed files with 451 additions and 4 deletions
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85
doc/src/sgml/pageinspect.sgml
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@ -300,6 +300,91 @@ brintest-# order by blknum, attnum limit 6;
</listitem>
</varlistentry>
<varlistentry>
<term>
<function>gin_metapage_info(page bytea) returns record</function>
<indexterm>
<primary>gin_metapage_info</primary>
</indexterm>
</term>
<listitem>
<para>
<function>gin_metapage_info</function> returns information about
a <acronym>GIN</acronym> index metapage. For example:
<screen>
test=# SELECT * FROM gin_metapage_info(get_raw_page('gin_index', 0));
-[ RECORD 1 ]----+-----------
pending_head | 4294967295
pending_tail | 4294967295
tail_free_size | 0
n_pending_pages | 0
n_pending_tuples | 0
n_total_pages | 7
n_entry_pages | 6
n_data_pages | 0
n_entries | 693
version | 2
</screen>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<function>gin_page_opaque_info(page bytea) returns record</function>
<indexterm>
<primary>gin_page_opaque_info</primary>
</indexterm>
</term>
<listitem>
<para>
<function>gin_page_opaque_info</function> returns information about
a <acronym>GIN</acronym> index opaque area, like the page type.
For example:
<screen>
test=# SELECT * FROM gin_page_opaque_info(get_raw_page('gin_index', 2));
rightlink | maxoff | flags
-----------+--------+------------------------
5 | 0 | {data,leaf,compressed}
(1 row)
</screen>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<function>gin_leafpage_items(page bytea) returns setof record</function>
<indexterm>
<primary>gin_leafpage_items</primary>
</indexterm>
</term>
<listitem>
<para>
<function>gin_leafpage_items</function> returns information about
the data stored in a <acronym>GIN</acronym> leaf page. For example:
<screen>
test=# SELECT first_tid, nbytes, tids[0:5] as some_tids
FROM gin_leafpage_items(get_raw_page('gin_test_idx', 2));
first_tid | nbytes | some_tids
-----------+--------+----------------------------------------------------------
(8,41) | 244 | {"(8,41)","(8,43)","(8,44)","(8,45)","(8,46)"}
(10,45) | 248 | {"(10,45)","(10,46)","(10,47)","(10,48)","(10,49)"}
(12,52) | 248 | {"(12,52)","(12,53)","(12,54)","(12,55)","(12,56)"}
(14,59) | 320 | {"(14,59)","(14,60)","(14,61)","(14,62)","(14,63)"}
(167,16) | 376 | {"(167,16)","(167,17)","(167,18)","(167,19)","(167,20)"}
(170,30) | 376 | {"(170,30)","(170,31)","(170,32)","(170,33)","(170,34)"}
(173,44) | 197 | {"(173,44)","(173,45)","(173,46)","(173,47)","(173,48)"}
(7 rows)
</screen>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<function>fsm_page_contents(page bytea) returns text</function>