EXPLAIN¶

Synopsis

EXPLAIN [GLOBAL] statement

Description

Show the logical or global execution plan of a statement.

Examples

Logical plan:

default> EXPLAIN SELECT l_orderkey, count(*) FROM lineitem GROUP BY l_orderkey;
explain
-------------------------------
GROUP_BY(1)(l_orderkey)
  => exprs: (count())
  => target list: default.lineitem.l_orderkey (INT8), ?count (INT8)
  => out schema:{(2) default.lineitem.l_orderkey (INT8), ?count (INT8)}
  => in schema:{(1) default.lineitem.l_orderkey (INT8)}
   SCAN(0) on default.lineitem
     => target list: default.lineitem.l_orderkey (INT8)
     => out schema: {(1) default.lineitem.l_orderkey (INT8)}
     => in schema: {(16) default.lineitem.l_orderkey (INT8), default.lineitem.l_partkey (INT8), default.lineitem.l_suppkey (INT8), default.lineitem.l_linenumber (INT8), default.lineitem.l_quantity (FLOAT8), default.lineitem.l_extendedprice (FLOAT8), default.lineitem.l_discount (FLOAT8), default.lineitem.l_tax (FLOAT8), default.lineitem.l_returnflag (TEXT), default.lineitem.l_linestatus (TEXT), default.lineitem.l_shipdate (DATE), default.lineitem.l_commitdate (DATE), default.lineitem.l_receiptdate (DATE), default.lineitem.l_shipinstruct (TEXT), default.lineitem.l_shipmode (TEXT), default.lineitem.l_comment (TEXT)}

Global plan:

default> EXPLAIN GLOBAL SELECT l_orderkey, count(*) FROM lineitem GROUP BY l_orderkey;
explain
-------------------------------
-------------------------------------------------------------------------------
Execution Block Graph (TERMINAL - eb_0000000000000_0000_000003)
-------------------------------------------------------------------------------
|-eb_0000000000000_0000_000003
   |-eb_0000000000000_0000_000002
      |-eb_0000000000000_0000_000001
-------------------------------------------------------------------------------
Order of Execution
-------------------------------------------------------------------------------
1: eb_0000000000000_0000_000001
2: eb_0000000000000_0000_000002
3: eb_0000000000000_0000_000003
-------------------------------------------------------------------------------

=======================================================
Block Id: eb_0000000000000_0000_000001 [LEAF]
=======================================================

[Outgoing]
[q_0000000000000_0000] 1 => 2 (type=HASH_SHUFFLE, key=default.lineitem.l_orderkey (INT8), num=32)

GROUP_BY(5)(l_orderkey)
  => exprs: (count())
  => target list: default.lineitem.l_orderkey (INT8), ?count_1 (INT8)
  => out schema:{(2) default.lineitem.l_orderkey (INT8), ?count_1 (INT8)}
  => in schema:{(1) default.lineitem.l_orderkey (INT8)}
   SCAN(0) on default.lineitem
     => target list: default.lineitem.l_orderkey (INT8)
     => out schema: {(1) default.lineitem.l_orderkey (INT8)}
     => in schema: {(16) default.lineitem.l_orderkey (INT8), default.lineitem.l_partkey (INT8), default.lineitem.l_suppkey (INT8), default.lineitem.l_linenumber (INT8), default.lineitem.l_quantity (FLOAT8), default.lineitem.l_extendedprice (FLOAT8), default.lineitem.l_discount (FLOAT8), default.lineitem.l_tax (FLOAT8), default.lineitem.l_returnflag (TEXT), default.lineitem.l_linestatus (TEXT), default.lineitem.l_shipdate (DATE), default.lineitem.l_commitdate (DATE), default.lineitem.l_receiptdate (DATE), default.lineitem.l_shipinstruct (TEXT), default.lineitem.l_shipmode (TEXT), default.lineitem.l_comment (TEXT)}

=======================================================
Block Id: eb_0000000000000_0000_000002 [ROOT]
=======================================================

[Incoming]
[q_0000000000000_0000] 1 => 2 (type=HASH_SHUFFLE, key=default.lineitem.l_orderkey (INT8), num=32)

GROUP_BY(1)(l_orderkey)
  => exprs: (count(?count_1 (INT8)))
  => target list: default.lineitem.l_orderkey (INT8), ?count (INT8)
  => out schema:{(2) default.lineitem.l_orderkey (INT8), ?count (INT8)}
  => in schema:{(2) default.lineitem.l_orderkey (INT8), ?count_1 (INT8)}
   SCAN(6) on eb_0000000000000_0000_000001
     => out schema: {(2) default.lineitem.l_orderkey (INT8), ?count_1 (INT8)}
     => in schema: {(2) default.lineitem.l_orderkey (INT8), ?count_1 (INT8)}

=======================================================
Block Id: eb_0000000000000_0000_000003 [TERMINAL]
=======================================================