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can tell whether it is being used as an aggregate or not. This allows such a function to avoid re-pallocing a pass-by-reference transition value; normally it would be unsafe for a function to scribble on an input, but in the aggregate case it's safe to reuse the old transition value. Make int8inc() do this. This gets a useful improvement in the speed of COUNT(*), at least on narrow tables (it seems to be swamped by I/O when the table rows are wide). Per a discussion in early December with Neil Conway. I also fixed int_aggregate.c to check this, thereby turning it into something approaching a supportable technique instead of being a crude hack.
34 lines
1010 B
MySQL
34 lines
1010 B
MySQL
-- Adjust this setting to control where the objects get created.
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SET search_path = public;
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-- Internal function for the aggregate
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-- Is called for each item in an aggregation
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CREATE OR REPLACE FUNCTION int_agg_state (int4[], int4)
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RETURNS int4[]
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AS 'MODULE_PATHNAME','int_agg_state'
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LANGUAGE C;
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-- Internal function for the aggregate
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-- Is called at the end of the aggregation, and returns an array.
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CREATE OR REPLACE FUNCTION int_agg_final_array (int4[])
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RETURNS int4[]
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AS 'MODULE_PATHNAME','int_agg_final_array'
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LANGUAGE C;
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-- The aggregate function itself
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-- uses the above functions to create an array of integers from an aggregation.
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CREATE AGGREGATE int_array_aggregate (
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BASETYPE = int4,
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SFUNC = int_agg_state,
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STYPE = int4[],
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FINALFUNC = int_agg_final_array
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);
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-- The enumeration function
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-- returns each element in a one dimensional integer array
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-- as a row.
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CREATE OR REPLACE FUNCTION int_array_enum(int4[])
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RETURNS setof integer
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AS 'MODULE_PATHNAME','int_enum'
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LANGUAGE C IMMUTABLE STRICT;
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