PICTURE

Preceding an SQL statement by PICTURE produces a pictorial representation that describes how the optimizer will handle the command or request. Picture is discussed in detail in the Kognitio Guide.

Usage

PICTURE query-statement

Notes

The query is not executed by Kognitio, when preceded by PICTURE, rather the optimizer’s execution plan is returned in pictorial form.

Terminology

The following table lists the abbreviations used in the PICTURE output.

Term

Description

BTX

Base Table x

TTX

Temporary Table x

VIX

View Image x

RAND

Random distribution

HASH

Hashed distribution

REP

Replicated distribution

FILTER

Remove rows meeting a WHERE condition

AGG

Aggregation (Count, Average, Max, Min, Sum)

ORD_BY

Order By

GRP_BY

Group By

EQUIJN

equi join

LCIN

left corr join. in subquerry

LCNIN

left corr join. not in subquerry

RCIN

right corr join. in subquerry

RCNIN

right corr join. not in subquerry

LIN

left non-corr join in subquerry

LNIN

left non-corr join not in subquery

RIN

right non-corr join in subquery

RNIN

right non-corr join not in subquery

LOUTER

left outer join

ROUTER

right outer join

LOUTEX

left outer exclusive join

ROUTEX

right outer exclusive join

THETA

theta join or full cartesian join

Example

Obtain a picture for the query used in the EXPLAIN Example:

PICTURE SELECT b1.c0, b2.c4
FROM edp_big1 b1, edp_big2 b2
WHERE b1.c1 < 0.0 AND b1.c0 = b2.c0
  DESCRIBE_TEXT
     RETURN
   --EQUIJN--
  |         |
 HASH      HASH
  TT1       TT2
 LOAD      LOAD
FILTER      |
  |        DISK
DISK        BT2
 BT1

BT1 - EDP_BIG1(1042) is on disk

BT2 - EDP_BIG2(1044) is on disk

-- Estimated Total Cost : 205.822