Profiler Speculative Feature: Query plans

time to read 5 min | 827 words

This isn’t a new feature, because you can’t use it right now, but it is a really nice feature that we are working on, and I couldn’t resist showing it off hot “off the press”, so to speak.

Given the following query:

SELECT             AS id7_1_,
       this_.title          AS title7_1_,
       this_.subtitle       AS subtitle7_1_,
       this_.allowscomments AS allowsco4_7_1_,
       this_.createdat      AS createdat7_1_,
       posts2_.blogid       AS blogid3_,           AS id3_,           AS id0_0_,
       posts2_.title        AS title0_0_,
       posts2_.TEXT         AS text0_0_,
       posts2_.postedat     AS postedat0_0_,
       posts2_.blogid       AS blogid0_0_,
       posts2_.userid       AS userid0_0_
FROM   blogs this_
       LEFT OUTER JOIN posts posts2_
         ON = posts2_.blogid
WHERE = 1 /* @p0 */

SELECT            AS id0_1_,
       this_.title         AS title0_1_,
       this_.TEXT          AS text0_1_,
       this_.postedat      AS postedat0_1_,
       this_.blogid        AS blogid0_1_,
       this_.userid        AS userid0_1_,
       comments2_.postid   AS postid3_,       AS id3_,       AS id2_0_,     AS name2_0_,    AS email2_0_,
       comments2_.homepage AS homepage2_0_,
       comments2_.ip       AS ip2_0_,
       comments2_.TEXT     AS text2_0_,
       comments2_.postid   AS postid2_0_
FROM   posts this_
       LEFT OUTER JOIN comments comments2_
         ON = comments2_.postid
WHERE  this_.blogid = 1 /* @p1 */

The profiler can show you the query plan using this UI:


And here is how the same query looks like using the query plan feature in Management Studio:


So, why implement it?

  • This isn’t limited to SQL Server, the profiler can display query plans for: SQL Server, Oracle, PostgreSQL and MySQL
  • This let you keep yourself in the flow, just hit a button to see the query plan, instead of copying the SQL, opening SSMS, displaying the query plan, etc.

Don’t discount the last one, making it easy is one of the core values of the profiler.

The idea is that if you make it easy enough, the barriers for using it goes away. If you can instantly see the query plan for a query, you are far more likely to look at it than if it takes 30 seconds to get that. At that point, you would only do it when you already have a performance problem.