spatial_index_read_extent()

static GBOX * spatial_index_read_extent ( Oid  idx_oid, int  idx_att_num, int  key_type  )

static

Definition at line 2442 of file gserialized_estimate.c.

{
        BOX2DF *bounds_2df = NULL;
        GIDX *bounds_gidx = NULL;
        GBOX *gbox = NULL;
        Relation idx_rel;
        Buffer buffer;
        Page page;
        unsigned long offset;
        unsigned long offset_max;
 
        if (!idx_oid)
                return NULL;
 
        idx_rel = index_open(idx_oid, AccessShareLock);
        buffer = ReadBuffer(idx_rel, GIST_ROOT_BLKNO);
        page = (Page) BufferGetPage(buffer);
        offset = FirstOffsetNumber;
        offset_max = PageGetMaxOffsetNumber(page);
        while (offset <= offset_max)
        {
                ItemId iid = PageGetItemId(page, offset);
                IndexTuple ituple;
                if (!iid)
                {
                        ReleaseBuffer(buffer);
                        index_close(idx_rel, AccessShareLock);
                        return NULL;
                }
                ituple = (IndexTuple) PageGetItem(page, iid);
                if (!GistTupleIsInvalid(ituple))
                {
                        bool isnull;
                        Datum idx_attr = index_getattr(ituple, idx_att_num, idx_rel->rd_att, &isnull);
                        if (!isnull)
                        {
                                if (key_type == STATISTIC_KIND_2D)
                                {
                                        BOX2DF *b = (BOX2DF*)DatumGetPointer(idx_attr);
                                        if (bounds_2df)
                                                box2df_merge(bounds_2df, b);
                                        else
                                                bounds_2df = box2df_copy(b);
                                }
                                else
                                {
                                        GIDX *b = (GIDX*)DatumGetPointer(idx_attr);
                                        if (bounds_gidx)
                                                gidx_merge(&bounds_gidx, b);
                                        else
                                                bounds_gidx = gidx_copy(b);
                                }
                        }
                }
                offset++;
        }
 
        ReleaseBuffer(buffer);
        index_close(idx_rel, AccessShareLock);
 
        if (key_type == STATISTIC_KIND_2D && bounds_2df)
        {
                if (box2df_is_empty(bounds_2df))
                        return NULL;
                gbox = gbox_new(0);
                box2df_to_gbox_p(bounds_2df, gbox);
        }
        else if (key_type == STATISTIC_KIND_ND && bounds_gidx)
        {
                lwflags_t flags = 0;
                if (gidx_is_unknown(bounds_gidx))
                        return NULL;
                FLAGS_SET_Z(flags, GIDX_NDIMS(bounds_gidx) > 2);
                FLAGS_SET_M(flags, GIDX_NDIMS(bounds_gidx) > 3);
                gbox = gbox_new(flags);
                gbox_from_gidx(bounds_gidx, gbox, flags);
        }
        else
                return NULL;
 
        return gbox;
}

References box2df_copy(), box2df_is_empty(), box2df_merge(), box2df_to_gbox_p(), buffer(), FLAGS_SET_M, FLAGS_SET_Z, gbox_new(), gidx_copy(), gidx_is_unknown(), gidx_merge(), STATISTIC_KIND_2D, and STATISTIC_KIND_ND.

Referenced by _postgis_gserialized_index_extent(), and gserialized_estimated_extent().

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