what is "show execution plan" in sql server?

i am using sql server 2008

i am looking at the activity monitor

i selected one of the queries and right clicked and selected show execution plan

this opened up a nifty flow chart. what does all this stuff mean??????

From serverfault I__

• The option to Show Execution Plan essentially outlines how SQL Server actually executes your query.

  For instance, you might implicitly join two tables, but the SQL Server Execution Plan will show the actual joins.

  Show Execution Plan can also help you spot queries that might get caught in a loop unexpectedly and other issues that are sometimes forgotten when writing a long or complicated query (like joining table A to table B then back to table A - friend did this once).

  From Daniel Mallott