PostGIS  3.7.0dev-r@@SVN_REVISION@@

◆ _postgis_gserialized_sel()

Datum _postgis_gserialized_sel ( PG_FUNCTION_ARGS  )

Definition at line 2101 of file gserialized_estimate.c.

2102 {
2103  Oid table_oid = PG_GETARG_OID(0);
2104  text *att_text = PG_GETARG_TEXT_P(1);
2105  Datum geom_datum = PG_GETARG_DATUM(2);
2106  GBOX gbox; /* search box read from gserialized datum */
2107  float8 selectivity = 0;
2108  ND_STATS *nd_stats;
2109  int mode = 2; /* 2D mode by default */
2110 
2111  /* Check if we've been asked to not use 2d mode */
2112  if ( ! PG_ARGISNULL(3) )
2113  mode = text_p_get_mode(PG_GETARG_TEXT_P(3));
2114 
2115  /* Retrieve the stats object */
2116  nd_stats = pg_get_nd_stats_by_name(table_oid, att_text, mode, false);
2117 
2118  if ( ! nd_stats )
2119  elog(ERROR, "stats for \"%s.%s\" do not exist", get_rel_name(table_oid), text_to_cstring(att_text));
2120 
2121  /* Calculate the gbox */
2122  if ( ! gserialized_datum_get_gbox_p(geom_datum, &gbox) )
2123  elog(ERROR, "unable to calculate bounding box from geometry");
2124 
2125  POSTGIS_DEBUGF(3, " %s", gbox_to_string(&gbox));
2126 
2127  /* Do the estimation */
2128  selectivity = estimate_selectivity(&gbox, nd_stats, mode);
2129 
2130  pfree(nd_stats);
2131  PG_RETURN_FLOAT8(selectivity);
2132 }
char * gbox_to_string(const GBOX *gbox)
Allocate a string representation of the GBOX, based on dimensionality of flags.
Definition: gbox.c:404
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.
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'.
int gserialized_datum_get_gbox_p(Datum gsdatum, GBOX *gbox)
Given a GSERIALIZED datum, as quickly as possible (peaking into the top of the memory) return the gbo...
N-dimensional statistics structure.

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

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