Github user decibel commented on a diff in the pull request: https://github.com/apache/incubator-madlib/pull/78#discussion_r92069636 --- Diff: src/ports/postgres/modules/graph/sssp.py_in --- @@ -0,0 +1,347 @@ +# coding=utf-8 +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +# Single Source Shortest Path + +# Please refer to the sssp.sql_in file for the documentation + +""" +@file sssp.py_in + +@namespace graph +""" + +import plpy +from utilities.control import MinWarning +from utilities.utilities import _assert +from utilities.utilities import extract_keyvalue_params +from utilities.utilities import unique_string +from utilities.validate_args import get_cols +from utilities.validate_args import unquote_ident +from utilities.validate_args import table_exists +from utilities.validate_args import columns_exist_in_table +from utilities.validate_args import table_is_empty + +m4_changequote(`<!', `!>') + +def graph_sssp(schema_madlib, vertex_table, vertex_id, edge_table, + edge_args, source_vertex, out_table, **kwargs): + """ + Single source shortest path function for graphs + Args: + @param vertex_table Name of the table that contains the vertex data. + @param vertex_id Name of the column containing the vertex ids. + @param edge_table Name of the table that contains the edge data. + @param edge_args A comma-delimited string containing multiple + named arguments of the form "name=value". + @param source_vertex The source vertex id for the algorithm to start. + @param out_table Name of the table to store the result of SSSP. + """ + + with MinWarning("warning"): + + INT_MAX = 2147483647 + + message = unique_string(desp='message') + toupdate = unique_string(desp='toupdate') + + params_types = {'src': str, 'dest': str, 'weight': str} + default_args = {'src': 'src', 'dest': 'dest', 'weight': 'weight'} + edge_params = extract_keyvalue_params(edge_args, + params_types, + default_args) + if vertex_id is None: + vertex_id = "id" + + src = edge_params["src"] + dest = edge_params["dest"] + weight = edge_params["weight"] + + distribution = m4_ifdef(<!__POSTGRESQL__!>, <!''!>, + <!"DISTRIBUTED BY ({0})".format(vertex_id)!>) + local_distribution = m4_ifdef(<!__POSTGRESQL__!>, <!''!>, + <!"DISTRIBUTED BY (id)"!>) + + validate_graph_coding(vertex_table, vertex_id, edge_table, + edge_params, source_vertex, out_table) + + plpy.execute(" DROP TABLE IF EXISTS {0},{1}".format(message,toupdate)) + + plpy.execute( + """ CREATE TABLE {out_table} AS --- End diff -- Well, as I mentioned, I think there's a good chance that this could be done without any temporary storage. But part of the idea of doing this would be usability; a user could do whatever they wanted with an SRF, whether that was loading it into a table, using in a COPY command, etc. That said, I don't think it's a huge deal, since most other functions create real tables for their output.
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