PostGIS  3.1.6dev-r@@SVN_REVISION@@

◆ _postgis_gserialized_joinsel()

Datum _postgis_gserialized_joinsel ( PG_FUNCTION_ARGS  )

Definition at line 2155 of file gserialized_estimate.c.

2156 {
2157  Oid table_oid1 = PG_GETARG_OID(0);
2158  text *att_text1 = PG_GETARG_TEXT_P(1);
2159  Oid table_oid2 = PG_GETARG_OID(2);
2160  text *att_text2 = PG_GETARG_TEXT_P(3);
2161  ND_STATS *nd_stats1, *nd_stats2;
2162  float8 selectivity = 0;
2163  int mode = 2; /* 2D mode by default */
2164 
2165 
2166  /* Retrieve the stats object */
2167  nd_stats1 = pg_get_nd_stats_by_name(table_oid1, att_text1, mode, false);
2168  nd_stats2 = pg_get_nd_stats_by_name(table_oid2, att_text2, mode, false);
2169 
2170  if ( ! nd_stats1 )
2171  elog(ERROR, "stats for \"%s.%s\" do not exist", get_rel_name(table_oid1), text_to_cstring(att_text1));
2172 
2173  if ( ! nd_stats2 )
2174  elog(ERROR, "stats for \"%s.%s\" do not exist", get_rel_name(table_oid2), text_to_cstring(att_text2));
2175 
2176  /* Check if we've been asked to not use 2d mode */
2177  if ( ! PG_ARGISNULL(4) )
2178  {
2179  text *modetxt = PG_GETARG_TEXT_P(4);
2180  char *modestr = text_to_cstring(modetxt);
2181  if ( modestr[0] == 'N' )
2182  mode = 0;
2183  }
2184 
2185  /* Do the estimation */
2186  selectivity = estimate_join_selectivity(nd_stats1, nd_stats2);
2187 
2188  pfree(nd_stats1);
2189  pfree(nd_stats2);
2190  PG_RETURN_FLOAT8(selectivity);
2191 }
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_join_selectivity(const ND_STATS *s1, const ND_STATS *s2)
Given two statistics histograms, what is the selectivity of a join driven by the && or &&& operator?
N-dimensional statistics structure.

References estimate_join_selectivity(), and pg_get_nd_stats_by_name().

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