Displaying Bottleneck Candidates

Bottleneck candidates are SQL statements that meet the conditions that you have defined for the SQL performance analysis.

You are logged on to the database as the database system administrator or as a database user.
The database is in the ONLINE operational state.

In the context menu of the database system administrator or the logged-on database user, choose Performance SQL Performance Analysis . Configure the SQL performance analysis as described in Configuring the SQL Performance Analysis.
At the bottom of the page, enter the number of SQL statements that you want to display and choose Get Bottleneck Candidates.

You can configure filters. The following filter types are available:

Cumulative filters (for example cumulated read pages, runtime, selectivity)
These filters use the information that the system collects during simple SQL monitoring. The system accumulates the properties of the single executions for each SQL statement.

They help you find those SQL statements that the system runs frequently. Minor improvements in the performance of such SQL statements can result in large performance gains in the overall system.
Single filters (for example read pages, runtime, selectivity)
They help you find those SQL statements for which single executions are particularly slow (for example only for specific parameter values).

Choose a filter from list to add to the analysis.

Performance Analysis: Filters
Filter Name	Filter Condition
Cumulated Read Pages	Total pages accessed by all executions of individual SQL statements
Cumulated Runtime	Total runtime (in s) of all executions of individual SQL statements
Cumulated Selectivity	Total selectivity (in s) of all executions of individual SQL statements
Read Pages	Pages accessed by single executions of individual SQL statements
Runtime	Runtime (in ms) of single executions of individual SQL statements
Selectivity	Selectivity (in %) of single executions of individual SQL statements

In the section Filter Detail below the filter table, enter a value for the filter condition.
Choose Add.
Only SQL statements that fulfill at least one of the filter conditions are displayed from now on (OR operator).

Select the filter in the filter table and choose Remove.

In the Bottleneck Candidates section you can refresh the list of bottleneck candidates.
In the bottleneck candidates list, select the bottleneck candidate.
Double click or choose (Bottleneck Candidate Details).
The Bottleneck Candidate Detail tab page is displayed. For more information, see Analyzing Bottleneck Candidates.

You can choose the start time from which bottleneck candidates are displayed:

The default layout of the bottleneck candidates list includes the most frequently used columns.

To change the layout, choose (Table Layout) and add or remove columns.

Display variants are pre-defined column sets. You can choose different display variants from the Display Variant list.

Bottleneck Candidates: Display Variants
Display Variant	Description
Default	Most important values
MCOD + LVC	Contains columns that are only available in specific SAP installations
IO Details	Focus on the I/O behavior
Physical Read Details	Focus on the physical reading behavior
Physical Write Details	Focus on the physical writing behavior
Wait Details	Focus on waiting situations
Caller Details	Focus on the calling application
Bridge Details	Contains special counters for bridge scenarios

To change the definition of a display variant:

You can sort the results by click on the respective column header.

To specify multiple sorting criteria, choose Sorting (Sorting).

SAP Note 819641 (FAQ: MaxDB Performance)