table_get_spatial_index()

static Oid table_get_spatial_index ( Oid  tbl_oid, text *  col, int *  key_type, int *  att_num  )

static

Definition at line 2421 of file gserialized_estimate.c.

{
        Relation tbl_rel;
        ListCell *lc;
        List *idx_list;
        Oid result = InvalidOid;
        char *colname = text_to_cstring(col);
 
        /* Lookup our spatial index key types */
        Oid b2d_oid = postgis_oid(BOX2DFOID);
        Oid gdx_oid = postgis_oid(BOX3DOID);
 
        if (!(b2d_oid && gdx_oid))
                return InvalidOid;
 
        tbl_rel = RelationIdGetRelation(tbl_oid);
        idx_list = RelationGetIndexList(tbl_rel);
        RelationClose(tbl_rel);
 
        /* For each index associated with this table... */
        foreach(lc, idx_list)
        {
                Form_pg_class idx_form;
                HeapTuple idx_tup;
                int idx_relam;
                Oid idx_oid = lfirst_oid(lc);
 
                idx_tup = SearchSysCache1(RELOID, ObjectIdGetDatum(idx_oid));
                if (!HeapTupleIsValid(idx_tup))
                        elog(ERROR, "%s: unable to lookup index %u in syscache", __func__, idx_oid);
                idx_form = (Form_pg_class) GETSTRUCT(idx_tup);
                idx_relam = idx_form->relam;
                ReleaseSysCache(idx_tup);
 
                /* Does the index use a GIST access method? */
                if (idx_relam == GIST_AM_OID)
                {
                        Form_pg_attribute att;
                        Oid atttypid;
                        int attnum;
                        /* Is the index on the column name we are looking for? */
                        HeapTuple att_tup = SearchSysCache2(ATTNAME,
                                                            ObjectIdGetDatum(idx_oid),
                                                            PointerGetDatum(colname));
                        if (!HeapTupleIsValid(att_tup))
                                continue;
 
                        att = (Form_pg_attribute) GETSTRUCT(att_tup);
                        atttypid = att->atttypid;
                        attnum = att->attnum;
                        ReleaseSysCache(att_tup);
 
                        /* Is the column actually spatial? */
                        if (b2d_oid == atttypid || gdx_oid == atttypid)
                        {
                                /* Save result, clean up, and break out */
                                result = idx_oid;
                                if (att_num)
                                        *att_num = attnum;
                                if (key_type)
                                        *key_type = (atttypid == b2d_oid ? STATISTIC_KIND_2D : STATISTIC_KIND_ND);
                                break;
                        }
                }
        }
        return result;
}

References result, STATISTIC_KIND_2D, and STATISTIC_KIND_ND.

Referenced by _postgis_gserialized_index_extent(), and gserialized_estimated_extent().

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