PostGIS  2.5.0dev-r@@SVN_REVISION@@
Datum _postgis_gserialized_sel ( PG_FUNCTION_ARGS  )

Definition at line 2071 of file gserialized_estimate.c.

References estimate_selectivity(), gbox_to_string(), pg_get_nd_stats_by_name(), text2cstring(), and text_p_get_mode().

2072 {
2073  Oid table_oid = PG_GETARG_OID(0);
2074  text *att_text = PG_GETARG_TEXT_P(1);
2075  Datum geom_datum = PG_GETARG_DATUM(2);
2076  GBOX gbox; /* search box read from gserialized datum */
2077  float8 selectivity = 0;
2078  ND_STATS *nd_stats;
2079  int mode = 2; /* 2D mode by default */
2080 
2081  /* Check if we've been asked to not use 2d mode */
2082  if ( ! PG_ARGISNULL(3) )
2083  mode = text_p_get_mode(PG_GETARG_TEXT_P(3));
2084 
2085  /* Retrieve the stats object */
2086  nd_stats = pg_get_nd_stats_by_name(table_oid, att_text, mode, false);
2087 
2088  if ( ! nd_stats )
2089  elog(ERROR, "stats for \"%s.%s\" do not exist", get_rel_name(table_oid), text2cstring(att_text));
2090 
2091  /* Calculate the gbox */
2092  if ( ! gserialized_datum_get_gbox_p(geom_datum, &gbox) )
2093  elog(ERROR, "unable to calculate bounding box from geometry");
2094 
2095  POSTGIS_DEBUGF(3, " %s", gbox_to_string(&gbox));
2096 
2097  /* Do the estimation */
2098  selectivity = estimate_selectivity(&gbox, nd_stats, mode);
2099 
2100  pfree(nd_stats);
2101  PG_RETURN_FLOAT8(selectivity);
2102 }
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 int text_p_get_mode(const text *txt)
Utility function to see if the first letter of the mode argument is 'N'.
char * gbox_to_string(const GBOX *gbox)
Allocate a string representation of the GBOX, based on dimensionality of flags.
Definition: g_box.c:399
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...
char * text2cstring(const text *textptr)
N-dimensional statistics structure.

Here is the call graph for this function: