Local query plans

EXPLAIN LOCAL (on a multi-node database) shows the local query plans assigned to each node, which together comprise the total (global) query plan. If you omit this option, Vertica shows only the global query plan. Local query plans are shown only in DOT language source, which can be rendered in Graphviz.

For example, the following EXPLAIN statement includes the LOCAL option:

=> EXPLAIN LOCAL SELECT store_name, store_city, store_state
   FROM store.store_dimension ORDER BY store_state ASC, store_city ASC;

The output includes GraphViz source, which describes the local query plans assigned to each node. For example, output for this statement on a three-node database includes a GraphViz description of the following query plan for one node (v_vmart_node0003):

 -----------------------------------------------
 PLAN: v_vmart_node0003 (GraphViz Format)
 -----------------------------------------------
 digraph G {
 graph [rankdir=BT, label = "v_vmart_node0003\n", labelloc=t, labeljust=l ordering=out]
 0[label = "NewEENode \nOutBlk=[UncTuple(3)]", color = "green", shape = "box"];
 1[label = "Send\nSend to: v_vmart_node0001\nNet id: 1000\nMerge\n\nUnc: Char(2)\nUnc: Varchar(64)\nUnc: Varchar(64)", color = "green", shape = "box"];
 2[label = "Sort: (keys = A,A,N)\nUnc: Char(2)\nUnc: Varchar(64)\nUnc: Varchar(64)", color = "green", shape = "box"];
 3[label = "ExprEval: \n  store_dimension.store_state\n  store_dimension.store_city\n  store_dimension.store_name\nUnc: Char(2)\nUnc: Varchar(64)\nUnc: Varchar(64)
", color = "green", shape = "box"];
 4[label = "StorageUnionStep: store_dimension_p_b0\nUnc: Varchar(64)\nUnc: Varchar(64)\nUnc: Char(2)", color = "purple", shape = "box"];
 5[label = "ScanStep: store_dimension_p_b0\nstore_key (not emitted)\nstore_name\nstore_city\nstore_state\nUnc: Varchar(64)\nUnc: Varchar(64)\nUnc: Char(2)", color
= "brown", shape = "box"];
 1->0 [label = "0",color = "blue"];
 2->1 [label = "0",color = "blue"];
 3->2 [label = "0",color = "blue"];
 4->3 [label = "0",color = "blue"];
 5->4 [label = "0",color = "blue"];
 }

GraphViz renders this output as follows: