What is Stmm in Db2?

In a Db2 pureScale environment, each member has its own self-tuning memory manager (STMM) tuner, which actively tunes the memory configurations of the particular member that is based on dynamic workload characteristics and local resources.

How would you enable self tuning of memory areas that are controlled by memory configuration parameters?

To enable the self tuning of memory areas that are controlled by memory configuration parameters, set the relevant configuration parameters to AUTOMATIC using the UPDATE DATABASE CONFIGURATION command or the db2CfgSet API.

What is tuning memory?

A memory-tuning feature simplifies the task of memory configuration by automatically setting values for several memory configuration parameters.

What is memory tuning in Oracle?

Tuning memory allocation involves distributing available memory to Oracle memory structures. Oracle’s memory requirements depend on your application; therefore, you should tune memory allocation after tuning your application and SQL statements.

What is the importance of tuning memory allocation?

If you allocate memory before tuning your application and SQL statements, you may need to resize some Oracle memory structures to meet the needs of your modified statements and application. Tune memory allocation before you tune I/O. Allocating memory establishes the amount of I/O necessary for Oracle to operate.

How do I check my Oracle memory?

To get an idea for the different categories a process uses memory for, you can query the V$PROCESS_MEMORY table. This table shows the dynamic PGA memory usage for each Oracle processes and contains information, if used, for Java, PL/SQL, OLAP, and SQL areas.

What is a memory optimized table?

What are Memory Optimized Tables? A Memory Optimized Table, starting in SQL Server 2014, is simply a table that has two copies, one in active memory and one durable on disk whether that includes data or just Schema Only, which I will explain later.

What happens when a cursor is opened?

When a cursor is opened, the following things happen: The values of the bind variables are examined. Based on the values of the bind variables, the active set (the query result) is determined. The active set pointer is set to the first row.

What happens if CPU usage is high in Oracle?

Viewing CPU utilization for Oracle Oracle has many operations that are CPU intensive, and tuning can reduce CPU: Logical I/O (consistent gets) has high CPU overhead, and buffer touches can be reduced via SQL tuning (adding more selective indexes, materialized views). Library cache contention (high parses) drives-up CPU.

What is CPU utilization in Oracle?

Oracle CPU Utilization. V$SESSTAT shows Oracle CPU usage per session. You can use this view to determine which particular session is using the most CPU. V$RSRC_CONSUMER_GROUP shows CPU utilization statistics on a per consumer group basis, if you are running the Oracle Database Resource Manager.

How many indexes must a memory optimized table have?

one index
All memory-optimized tables must have at least one index, because it is the indexes that connect the rows together.

How do I create a memory optimized table?

Memory-optimized tables need at least one index to connect rows. This index can be a hash index or a nonclustered index. Individually for this table type, we chose the hash index type so we must set the bucket number. This number specifies the bucket number of the hash index.

How does the self tuning memory manager ( stmm ) work?

The Self-Tuning Memory Manger is a process that wakes up from time to time and reallocates how much memory several critical memory areas have allocated. It reallocates memory in specific ways based on the recent usage on the Db2 system STMM does not predict future or regular workloads and proactively allocate memory.

How to enable self tuning in DB2 memory manager?

STMM is enabled by setting the above parameters to AUTOMATIC, and setting the DB CFG parameter SELF_TUNING_MEM to ON. You can manually set any of the above parameters to exclude them from STMM’s dynamic changes, even if STMM is active. Simply set them to a static value. The package cache is one area you might want to consider this for.

Can you use stmm on a Blu database?

STMM cannot tune sort memory on BLU databases. It also cannot tune the utility heap, which is often very large in BLU databases. This means that STMM is a bit less useful for BLU. You could still use it to tune the remaining memory areas, which could still be 50% of your memory.

Which is better, a DBA or a stmm?

STMM does not predict future or regular workloads and proactively allocate memory. It does not prevent all possible out of memory conditions. It is a bit better for non-BLU systems, and has some restrictions on multi-partition systems. It is not a magic wand that will always do better than a DBA.