PostGIS 3.0.6dev-r@@SVN_REVISION@@
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◆ _postgis_gserialized_sel()

Datum _postgis_gserialized_sel ( PG_FUNCTION_ARGS  )

Definition at line 2106 of file gserialized_estimate.c.

2107{
2108 Oid table_oid = PG_GETARG_OID(0);
2109 text *att_text = PG_GETARG_TEXT_P(1);
2110 Datum geom_datum = PG_GETARG_DATUM(2);
2111 GBOX gbox; /* search box read from gserialized datum */
2112 float8 selectivity = 0;
2113 ND_STATS *nd_stats;
2114 int mode = 2; /* 2D mode by default */
2115
2116 /* Check if we've been asked to not use 2d mode */
2117 if ( ! PG_ARGISNULL(3) )
2118 mode = text_p_get_mode(PG_GETARG_TEXT_P(3));
2119
2120 /* Retrieve the stats object */
2121 nd_stats = pg_get_nd_stats_by_name(table_oid, att_text, mode, false);
2122
2123 if ( ! nd_stats )
2124 elog(ERROR, "stats for \"%s.%s\" do not exist", get_rel_name(table_oid), text_to_cstring(att_text));
2125
2126 /* Calculate the gbox */
2127 if ( ! gserialized_datum_get_gbox_p(geom_datum, &gbox) )
2128 elog(ERROR, "unable to calculate bounding box from geometry");
2129
2130 POSTGIS_DEBUGF(3, " %s", gbox_to_string(&gbox));
2131
2132 /* Do the estimation */
2133 selectivity = estimate_selectivity(&gbox, nd_stats, mode);
2134
2135 pfree(nd_stats);
2136 PG_RETURN_FLOAT8(selectivity);
2137}
char * gbox_to_string(const GBOX *gbox)
Allocate a string representation of the GBOX, based on dimensionality of flags.
Definition gbox.c:392
static float8 estimate_selectivity(const GBOX *box, const ND_STATS *nd_stats, int mode)
This function returns an estimate of the selectivity of a search GBOX by looking at data in the ND_ST...
static int text_p_get_mode(const text *txt)
Utility function to see if the first letter of the mode argument is 'N'.
static ND_STATS * pg_get_nd_stats_by_name(const Oid table_oid, const text *att_text, int mode, bool only_parent)
Pull the stats object from the PgSQL system catalogs.
char * text_to_cstring(const text *textptr)
N-dimensional statistics structure.

References estimate_selectivity(), gbox_to_string(), pg_get_nd_stats_by_name(), text_p_get_mode(), and text_to_cstring().

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