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BRIN is a new index access method intended to accelerate scans of very large tables, without the maintenance overhead of btrees or other traditional indexes. They work by maintaining "summary" data about block ranges. Bitmap index scans work by reading each summary tuple and comparing them with the query quals; all pages in the range are returned in a lossy TID bitmap if the quals are consistent with the values in the summary tuple, otherwise not. Normal index scans are not supported because these indexes do not store TIDs. As new tuples are added into the index, the summary information is updated (if the block range in which the tuple is added is already summarized) or not; in the latter case, a subsequent pass of VACUUM or the brin_summarize_new_values() function will create the summary information. For data types with natural 1-D sort orders, the summary info consists of the maximum and the minimum values of each indexed column within each page range. This type of operator class we call "Minmax", and we supply a bunch of them for most data types with B-tree opclasses. Since the BRIN code is generalized, other approaches are possible for things such as arrays, geometric types, ranges, etc; even for things such as enum types we could do something different than minmax with better results. In this commit I only include minmax. Catalog version bumped due to new builtin catalog entries. There's more that could be done here, but this is a good step forwards. Loosely based on ideas from Simon Riggs; code mostly by Álvaro Herrera, with contribution by Heikki Linnakangas. Patch reviewed by: Amit Kapila, Heikki Linnakangas, Robert Haas. Testing help from Jeff Janes, Erik Rijkers, Emanuel Calvo. PS: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 318633.
147 lines
3.1 KiB
SQL
147 lines
3.1 KiB
SQL
/* contrib/pageinspect/pageinspect--1.3.sql */
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-- complain if script is sourced in psql, rather than via CREATE EXTENSION
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\echo Use "CREATE EXTENSION pageinspect" to load this file. \quit
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--
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-- get_raw_page()
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--
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CREATE FUNCTION get_raw_page(text, int4)
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RETURNS bytea
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AS 'MODULE_PATHNAME', 'get_raw_page'
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LANGUAGE C STRICT;
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CREATE FUNCTION get_raw_page(text, text, int4)
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RETURNS bytea
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AS 'MODULE_PATHNAME', 'get_raw_page_fork'
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LANGUAGE C STRICT;
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--
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-- page_header()
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--
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CREATE FUNCTION page_header(IN page bytea,
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OUT lsn pg_lsn,
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OUT checksum smallint,
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OUT flags smallint,
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OUT lower smallint,
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OUT upper smallint,
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OUT special smallint,
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OUT pagesize smallint,
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OUT version smallint,
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OUT prune_xid xid)
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AS 'MODULE_PATHNAME', 'page_header'
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LANGUAGE C STRICT;
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--
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-- heap_page_items()
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--
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CREATE FUNCTION heap_page_items(IN page bytea,
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OUT lp smallint,
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OUT lp_off smallint,
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OUT lp_flags smallint,
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OUT lp_len smallint,
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OUT t_xmin xid,
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OUT t_xmax xid,
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OUT t_field3 int4,
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OUT t_ctid tid,
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OUT t_infomask2 integer,
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OUT t_infomask integer,
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OUT t_hoff smallint,
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OUT t_bits text,
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OUT t_oid oid)
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RETURNS SETOF record
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AS 'MODULE_PATHNAME', 'heap_page_items'
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LANGUAGE C STRICT;
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--
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-- bt_metap()
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--
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CREATE FUNCTION bt_metap(IN relname text,
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OUT magic int4,
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OUT version int4,
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OUT root int4,
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OUT level int4,
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OUT fastroot int4,
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OUT fastlevel int4)
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AS 'MODULE_PATHNAME', 'bt_metap'
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LANGUAGE C STRICT;
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--
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-- bt_page_stats()
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--
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CREATE FUNCTION bt_page_stats(IN relname text, IN blkno int4,
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OUT blkno int4,
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OUT type "char",
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OUT live_items int4,
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OUT dead_items int4,
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OUT avg_item_size int4,
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OUT page_size int4,
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OUT free_size int4,
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OUT btpo_prev int4,
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OUT btpo_next int4,
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OUT btpo int4,
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OUT btpo_flags int4)
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AS 'MODULE_PATHNAME', 'bt_page_stats'
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LANGUAGE C STRICT;
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--
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-- bt_page_items()
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--
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CREATE FUNCTION bt_page_items(IN relname text, IN blkno int4,
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OUT itemoffset smallint,
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OUT ctid tid,
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OUT itemlen smallint,
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OUT nulls bool,
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OUT vars bool,
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OUT data text)
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RETURNS SETOF record
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AS 'MODULE_PATHNAME', 'bt_page_items'
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LANGUAGE C STRICT;
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--
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-- brin_page_type()
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--
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CREATE FUNCTION brin_page_type(IN page bytea)
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RETURNS text
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AS 'MODULE_PATHNAME', 'brin_page_type'
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LANGUAGE C STRICT;
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--
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-- brin_metapage_info()
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--
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CREATE FUNCTION brin_metapage_info(IN page bytea, OUT magic text,
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OUT version integer, OUT pagesperrange integer, OUT lastrevmappage bigint)
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AS 'MODULE_PATHNAME', 'brin_metapage_info'
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LANGUAGE C STRICT;
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--
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-- brin_revmap_data()
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CREATE FUNCTION brin_revmap_data(IN page bytea,
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OUT pages tid)
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RETURNS SETOF tid
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AS 'MODULE_PATHNAME', 'brin_revmap_data'
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LANGUAGE C STRICT;
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--
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-- brin_page_items()
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--
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CREATE FUNCTION brin_page_items(IN page bytea, IN index_oid regclass,
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OUT itemoffset int,
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OUT blknum int,
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OUT attnum int,
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OUT allnulls bool,
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OUT hasnulls bool,
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OUT placeholder bool,
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OUT value text)
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RETURNS SETOF record
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AS 'MODULE_PATHNAME', 'brin_page_items'
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LANGUAGE C STRICT;
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--
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-- fsm_page_contents()
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--
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CREATE FUNCTION fsm_page_contents(IN page bytea)
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RETURNS text
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AS 'MODULE_PATHNAME', 'fsm_page_contents'
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LANGUAGE C STRICT;
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