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Add cost estimation of range @> and <@ operators.

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The estimates are based on the existing lower bound histogram, and a new
histogram of range lengths.

Bump catversion, because the range length histogram now needs to be present
in statistic slot kind 6, or you get an error on @> and <@ queries. (A
re-ANALYZE would be enough to fix that, though)

Alexander Korotkov, with some refactoring by me.
This commit is contained in:
Heikki Linnakangas
2013-03-14 15:36:56 +02:00
parent 788bce13d3
commit 59d0bf9dca
5 changed files with 667 additions and 14 deletions
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2
src/include/catalog/catversion.h
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@@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201303101
#define CATALOG_VERSION_NO 201303141
#endif

1
src/include/catalog/pg_operator.h
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@@ -527,6 +527,7 @@ DATA(insert OID = 671 ( "<>" PGNSP PGUID b f f 701 701 16 671 670 float8ne
DESCR("not equal");
DATA(insert OID = 672 ( "<" PGNSP PGUID b f f 701 701 16 674 675 float8lt scalarltsel scalarltjoinsel ));
DESCR("less than");
#define Float8LessOperator 672
DATA(insert OID = 673 ( "<=" PGNSP PGUID b f f 701 701 16 675 674 float8le scalarltsel scalarltjoinsel ));
DESCR("less than or equal");
DATA(insert OID = 674 ( ">" PGNSP PGUID b f f 701 701 16 672 673 float8gt scalargtsel scalargtjoinsel ));

12
src/include/catalog/pg_statistic.h
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@@ -269,11 +269,15 @@ typedef FormData_pg_statistic *Form_pg_statistic;
#define STATISTIC_KIND_DECHIST 5
/*
* An "empty frac" slot describes the fraction of empty ranges in a range-type
* column. stavalues is not used and should be NULL. stanumbers contains a
* single entry, the fraction of empty ranges (0.0 to 1.0).
* A "length histogram" slot describes the distribution of range lengths in
* rows of a range-type column. stanumbers contains a single entry, the
* fraction of empty ranges. stavalues is a histogram of non-empty lengths, in
* a format similar to STATISTIC_KIND_HISTOGRAM: it contains M (>=2) range
* values that divide the column data values into M-1 bins of approximately
* equal population. The lengths are stores as float8s, as measured by the
* range type's subdiff function. Only non-null rows are considered.
*/
#define STATISTIC_KIND_RANGE_EMPTY_FRAC 6
#define STATISTIC_KIND_RANGE_LENGTH_HISTOGRAM 6
/*
* A "bounds histogram" slot is similar to STATISTIC_KIND_HISTOGRAM, but for