static void load_edge_hashtable()

in src/backend/utils/adt/age_global_graph.c [572:683]

• 83 lines of code
• 7 McCabe index (conditional complexity)

static void load_edge_hashtable(GRAPH_global_context *ggctx)
{
    Oid graph_oid;
    Oid graph_namespace_oid;
    Snapshot snapshot;
    List *edge_label_names = NIL;
    ListCell *lc;

    /* get the specific graph OID and namespace (schema) OID */
    graph_oid = ggctx->graph_oid;
    graph_namespace_oid = get_namespace_oid(ggctx->graph_name, false);
    /* get the active snapshot */
    snapshot = GetActiveSnapshot();
    /* get the names of all of the edge label tables */
    edge_label_names = get_ag_labels_names(snapshot, graph_oid,
                                           LABEL_TYPE_EDGE);
    /* go through all edge label tables in list */
    foreach (lc, edge_label_names)
    {
        Relation graph_edge_label;
        TableScanDesc scan_desc;
        HeapTuple tuple;
        char *edge_label_name;
        Oid edge_label_table_oid;
        TupleDesc tupdesc;

        /* get the edge label name */
        edge_label_name = lfirst(lc);
        /* get the edge label name's OID */
        edge_label_table_oid = get_relname_relid(edge_label_name,
                                                 graph_namespace_oid);
        /* open the relation (table) and begin the scan */
        graph_edge_label = table_open(edge_label_table_oid, ShareLock);
        scan_desc = table_beginscan(graph_edge_label, snapshot, 0, NULL);
        /* get the tupdesc - we don't need to release this one */
        tupdesc = RelationGetDescr(graph_edge_label);
        /* bail if the number of columns differs */
        if (tupdesc->natts != 4)
        {
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_TABLE),
                     errmsg("Invalid number of attributes for %s.%s",
                     ggctx->graph_name, edge_label_name)));
        }
        /* get all tuples in table and insert them into graph hashtables */
        while((tuple = heap_getnext(scan_desc, ForwardScanDirection)) != NULL)
        {
            graphid edge_id;
            graphid edge_vertex_start_id;
            graphid edge_vertex_end_id;
            Datum edge_properties;
            bool inserted = false;

            /* something is wrong if this isn't true */
            if (!HeapTupleIsValid(tuple))
            {
                elog(ERROR, "load_edge_hashtable: !HeapTupleIsValid");
            }
            Assert(HeapTupleIsValid(tuple));

            /* get the edge id */
            edge_id = DatumGetInt64(column_get_datum(tupdesc, tuple, 0, "id",
                                                     GRAPHIDOID, true));
            /* get the edge start_id (start vertex id) */
            edge_vertex_start_id = DatumGetInt64(column_get_datum(tupdesc,
                                                                  tuple, 1,
                                                                  "start_id",
                                                                  GRAPHIDOID,
                                                                  true));
            /* get the edge end_id (end vertex id)*/
            edge_vertex_end_id = DatumGetInt64(column_get_datum(tupdesc, tuple,
                                                                2, "end_id",
                                                                GRAPHIDOID,
                                                                true));
            /* get the edge properties datum */
            edge_properties = column_get_datum(tupdesc, tuple, 3, "properties",
                                               AGTYPEOID, true);

            /* we need to make a copy of the properties datum */
            edge_properties = datumCopy(edge_properties, false, -1);

            /* insert edge into edge hashtable */
            inserted = insert_edge_entry(ggctx, edge_id, edge_properties,
                                         edge_vertex_start_id,
                                         edge_vertex_end_id,
                                         edge_label_table_oid);

            /* warn if there is a duplicate */
            if (!inserted)
            {
                 ereport(WARNING,
                         (errcode(ERRCODE_DATA_EXCEPTION),
                          errmsg("ignored duplicate edge")));
            }

            /* insert the edge into the start and end vertices edge lists */
            inserted = insert_vertex_edge(ggctx, edge_vertex_start_id,
                                          edge_vertex_end_id, edge_id,
                                          edge_label_name);
            if (!inserted)
            {
                 ereport(WARNING,
                         (errcode(ERRCODE_DATA_EXCEPTION),
                          errmsg("ignored malformed or dangling edge")));
            }
        }

        /* end the scan and close the relation */
        table_endscan(scan_desc);
        table_close(graph_edge_label, ShareLock);
    }
}