Explain Plan Table Query,Wood Cutting Equipment Sales,louden custom woodworking - PDF 2016

25.11.2013, admin  
Category: Yard Furniture Plans

SELECT statements in order to see the steps of the execution plan for the statement you explained. You don’t need any special system privileges in order to use the EXPLAIN PLAN statement. GUI tools available that allow you to click on a SQL statement in the shared pool and view its execution plan.
EXPLAIN PLAN and TKPROF allow you to proactively tune an application while it is in development.
On the other hand, if large tables are accessed via selective indexes, then scalability may not be a problem. Before you can use the EXPLAIN PLAN statement, you must have INSERT privileges on a plan table. If you do not specify the INTO clause, then Oracle assumes the name of the plan table is plan_table.
In this section we will discuss how to read and interpret execution plans and TKPROF reports. This set of invoice records will be set aside for a moment while the focus turns to the customers table.
You may wonder how I got that whole detailed explanation out of the eight line execution plan listing shown above. HAVING clauses, while filter operations with multiple inputs will appear in queries with EXISTS clauses. This column will contain valuable information during parallel queries and distributed operations.


The row counts on the individual operations in an execution plan display can help identify inefficiencies. In this paper we have discussed how to generate execution plans and TKPROF reports, and how to interpret them.
Like the CBO regular queries, it is equally important to eliminate most of the rows as early as possible in the processing.
The :BF0000 shown is a Bloom Filter, a type of hash table that tracks the matching rows  from a join operation and prunes dependent on a Join condition. Individual partitions can be spread across processes using this granular approach to table block processing. I have been cleaning up query performance issues related to table variables quite regularly in the past 18 months or so. You can populate the remarks column by using an ordinary UPDATE statement against the plan table.
Review the query and see if there is a function or sub query on the partitioning key value that is not allowing for the pruning of partitions.
He has rewritten a stored procedure using table variable instead of temp table, it makes the stored procedure code look more tidy. The estimated plans looked the same using temp table and table variable, but the execution plans are very different.
Unbeknownst to him, rewriting the procedure using table variable bumped into a query optimizer blind spot. If a table (temporary or permanent) is created in the same batch with the query, SQL Serve has to recompile the query since the query definition is unknown when the batch is compiled the first time.


This is not the case for table variables (and that was the main reasons SQL Server 2005 introduce them – to reduce recompilations when unnecessary). The actual execution plan for script 2 uses Hash Match to execute the Anti Semi Join at the top of the plan. There is a table scan of the temporary table #Tmp1 at the top of the plan building the hash table.
If you examine the properties of this scan you will find out that the number of Estimated rows is 20000 (was 1 in the Estimated plan as well as it is 1 for the table variable plan). Actual plan of SELECT query using temp table When examining query plans be careful to consider possible plan change during the batch execution due to recompiles.
Bear in mind that while table variables are not causing recompiles, you may need just the opposite to get the best query plan. You should always use temporary tables in your queries unless you intentionally want to avoid query recompilation and you are confident query variable will give you a good plan.
Introduction of statement level recompilation in SQL Server 2005 substantially lowered the need to use table variables in your queries.




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