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PostgreSQL provides set of template index access methods, where opclasses have much freedom in the semantics of indexing. These index AMs are GiST, GIN, SP-GiST and BRIN. There opclasses define representation of keys, operations on them and supported search strategies. So, it's natural that opclasses may be faced some tradeoffs, which require user-side decision. This commit implements opclass parameters allowing users to set some values, which tell opclass how to index the particular dataset. This commit doesn't introduce new storage in system catalog. Instead it uses pg_attribute.attoptions, which is used for table column storage options but unused for index attributes. In order to evade changing signature of each opclass support function, we implement unified way to pass options to opclass support functions. Options are set to fn_expr as the constant bytea expression. It's possible due to the fact that opclass support functions are executed outside of expressions, so fn_expr is unused for them. This commit comes with some examples of opclass options usage. We parametrize signature length in GiST. That applies to multiple opclasses: tsvector_ops, gist__intbig_ops, gist_ltree_ops, gist__ltree_ops, gist_trgm_ops and gist_hstore_ops. Also we parametrize maximum number of integer ranges for gist__int_ops. However, the main future usage of this feature is expected to be json, where users would be able to specify which way to index particular json parts. Catversion is bumped. Discussion: https://postgr.es/m/d22c3a18-31c7-1879-fc11-4c1ce2f5e5af%40postgrespro.ru Author: Nikita Glukhov, revised by me Reviwed-by: Nikolay Shaplov, Robert Haas, Tom Lane, Tomas Vondra, Alvaro Herrera
21 lines
663 B
SQL
21 lines
663 B
SQL
/* contrib/intarray/intarray--1.2--1.3.sql */
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-- complain if script is sourced in psql, rather than via ALTER EXTENSION
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\echo Use "ALTER EXTENSION intarray UPDATE TO '1.3'" to load this file. \quit
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CREATE FUNCTION g_int_options(internal)
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RETURNS void
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AS 'MODULE_PATHNAME', 'g_int_options'
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LANGUAGE C IMMUTABLE PARALLEL SAFE;
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CREATE FUNCTION g_intbig_options(internal)
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RETURNS void
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AS 'MODULE_PATHNAME', 'g_intbig_options'
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LANGUAGE C IMMUTABLE PARALLEL SAFE;
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ALTER OPERATOR FAMILY gist__int_ops USING gist
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ADD FUNCTION 10 (_int4) g_int_options (internal);
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ALTER OPERATOR FAMILY gist__intbig_ops USING gist
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ADD FUNCTION 10 (_int4) g_intbig_options (internal);
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