Inspection

SQL - EXPLAIN

EXPLAIN SQL command returns information about query execution planning of a specific statement, without executing the statement itself.

Syntax

EXPLAIN <command>

  • <command> Defines the command that you want to profile, eg. a SELECT statement

Examples

  • Profile a query that executes on a type filtering based on an attribute:

  ArcadeDB {db=foo}> explain select from v where name = 'a'

  Profiled command '[{

  executionPlan:{...},

  executionPlanAsString:

  + FETCH FROM TYPE v
    + FETCH FROM BUCKET 9 ASC
    + FETCH FROM BUCKET 10 ASC
    + FETCH FROM BUCKET 11 ASC
    + FETCH FROM BUCKET 12 ASC
    + FETCH FROM BUCKET 13 ASC
    + FETCH FROM BUCKET 14 ASC
    + FETCH FROM BUCKET 15 ASC
    + FETCH FROM BUCKET 16 ASC
    + FETCH NEW RECORDS FROM CURRENT TRANSACTION SCOPE (if any)
  + FILTER ITEMS WHERE
    name = 'a'

  }]' in 0,022000 sec(s):

For more information, see:

SQL - PROFILE

The PROFILE SQL command returns information about query execution planning and statistics for a specific statement. The statement is actually executed to provide the execution stats.

The result is the execution plan of the query (like for EXPLAIN ) with additional information about execution time spent on each step, in microseconds.

Syntax

PROFILE <command>

  • <command> Defines the command that you want to profile, eg. a SELECT statement

Examples

PROFILE SELECT sum(Amount), OrderDate
FROM Orders
WHERE OrderDate > date("2012-12-09", "yyyy-MM-dd")
GROUP BY OrderDate

result:

+ FETCH FROM INDEX Orders.OrderDate (1.445μs)
  OrderDate > date("2012-12-09", "yyyy-MM-dd")
+ EXTRACT VALUE FROM INDEX ENTRY
+ FILTER ITEMS BY TYPE
  Orders
+ CALCULATE PROJECTIONS (5.065μs)
  Amount AS _$$$OALIAS$$_1, OrderDate
+ CALCULATE AGGREGATE PROJECTIONS (3.182μs)
  sum(_$$$OALIAS$$_1) AS _$$$OALIAS$$_0, OrderDate
  GROUP BY OrderDate
+ CALCULATE PROJECTIONS (1.116μs)
  _$$$OALIAS$$_0 AS `sum(Amount)`, OrderDate

You can see the (1.445μs) at the end of the first line, it means that fetching from index Orders.OrderDate took 1.445 microseconds (1.4 milliseconds)

For more information, see:

SQL - CONSOLE

Writes a string message of given log-level to the log. Log-levels are:

  • output (none)

  • log (INFO)

  • error (SEVERE)

  • warn (WARNING)

  • debug (FINE)

This command is useful for SQL scripts.
To flush to the log, suffix the message with a newline \n.

Syntax

CONSOLE.logLevel <expression>

The command returns which page have been aligned on each server.

Examples

  • Write a message of level INFO to the log.

CONSOLE.log map('Hello','World')