oracle database in-memory & multitenant - troug days'16 istanbul

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April 28-29, 2016Oracle Database In-Memory & MultitenantMahir M. Quluzade

2 Oracle Database In-Memory - Mahir M. Quluzade © 2016 http://www.mahir-quluzade.com

Mahir M. Quluzade

Oracle ACE AZEROUG (Azerbaijan Oracle User Group) TROUG (Turkish Oracle User Group) OCE 12c, 11g Author of OTech Magazine and OTN Articles Central Bank - Oracle DBA Oracle Blog : http//www.mahir-quluzade.com


What isOracle Multitenant?


Oracle Database Architecture

Oracle Instance– SGA & PGA – Background Processes

Oracle Database – Control Files– Data Files – Redo Logs (Online and Archived)– Parameter and Password file

Pre-12c Oracle Database

Database ServerMemory

BackgroundProcesses

DatabaseFiles


Oracle Database ArchitectureRequires memory, processes and database files

System Resources

ERPMemory

BackgroundProcesses

DatabaseFiles

CRMMemory

BackgroundProcesses

DatabaseFiles

DWMemory

BackgroundProcesses

DatabaseFiles


Container Database

New Multitenant ArchitectureMemory and processes required at multitenant container level only

System Resources

ERPMemory

BackgroundProcesses

DatabaseFiles

CRMMemory

BackgroundProcesses

DatabaseFiles

DWMemory

BackgroundProcesses

DatabaseFiles


New Multitenant ArchitectureMemory and processes required at multitenant container level only

System Resources

Container Database


Multitenant ArchitectureComponents of a Multitenant Container Database (CDB)

Multitenant Container DatabaseROOT

12.1

HCM12.1

DW12.1

CRM12.1

ERP12.1

Pluggable Databases (PDBs)

PDBs

Root

CDB

CREATE DATABASE … ENABLE PLUGGABLE DATABASE

Create CDB

CREATE PLUGGABLE DATABASE …Create PDB


Multitenant Architecture – Dynamics

PDBs share common SGA andbackground processes

Foreground sessions see only the PDB they connect to


What isOracle Database In-Memory?


Oracle Database In-Memory Goals


Breakthrough: Dual Format Database


What is changed in Oracle Instance?


What is changed in Oracle Instance?

SGA - System Global Area– Buffer Cache– Shared Pool– Redo Buffer– Large Pool– Other Memory Areas– In-Memory Area

Background Processes– DBWn– LGWR– …– Wnnn (worker processes ora_w00n_db_name)


In-Memory Area

Contains two sub-pools: – IMCU pool: Stores In Memory Compression Units (IMCUs)

– SMU pool: Stores Snapshot Metadata Units (SMUs)

IMCUs contain column formatted data SMUs contain metadata and transactional

information

In-Memory area is static area– 1MB Pool – Populated Columns Data– 64KB Pool – Objects Metadata


How to install and configure Oracle Database In-Memory?


Oracle Database In-Memory automatically installed as part of Oracle Database 12c Release 1 (12.1.0.2)

But not enabled by default

Installing: Oracle Database In-Memory


In-Memory Area

In-Memory control parameters starting “INMEMORY_” prefix Additional for optimizer control parameter OPTIMIZER_INMEMORY_AWARE

Core Initialization Parameters


Starting in Oracle Database 12c Release 2 (12.2), can increase INMEMORY_SIZE size dynamically by using ALTER SYSTEM. If free memory is available in the SGA, then the database allocates the memory to the IM column store.

Note: You cannot use ALTER SYSTEM to reduce INMEMORY_SIZE.

Enable In-Memory Area

SQL> alter system set memory_max_target=1324M scope=spfile;

SQL> alter system set inmemory_size=300M scope=spfile;

SQL> shutdown immediate;

SQL> startup ORACLE instance started. Total System Global Area 1392508928 bytes Fixed Size 2924304 bytes Variable Size 1040187632 bytes Database Buffers 16777216 bytes Redo Buffers 13852672 bytesIn-Memory Area 318767104 bytes Database mounted. Database opened.


How to configure In-Memory in Multitenant Container Database?


Parameters in Multitenant Container Database

V$SYSTEM_PARAMETERS.ISPDB_MODIFIABLE


Parameters in Multitenant Container Database


INMEMORY attributes in DDLs


Populating In-Memory Colum Store

SQL> CREATE TABLESAPCE users DATAFILE … INMEMORY;

SQL> ALTER TABLESPACE users INMEMORY;

– All new tables and materialized views in this tablespace will be enabled for IM column store by default.

INMEMORY attribute for Tablespaces



SQL> CREATE TABLE orders (ID NUMBER, …) INMEMORY;

SQL> ALTER TABLE orders INMEMORY;

Can exclude one or more not important columns for aggregation– SQL> ALTER TABLE orders INMEMORY NO INMEMORY(createuser_id);

Can disable IM Column Store for one or more partition– SQL> ALTER TABLE orders MODIFY PARTITION orders_p2000 NO INMEMORY;

INMEMORY attribute for Tables



SQL> CREATE MATERIALIZED VIEW sales_mv INMEMORY SELECT * FROM SALES;

SQL> SELECT table_name, inmemory, inmemory_priority, inmemory_distribute,

inmemory_compression FROM user_tables WHERE table_name = ‘SALES_MV'; TABLE_NAME INMEMORY INMEMORY_PRI INMEMORY_DISTRI INMEMORY_COMPRESS ---------- -------- ------------ --------------- ------------------- SALE_MV ENABLED NONE AUTO FOR QUERY LOW

INMEMORY attribute for Materialized Views



CRITICAL– Object is populated immediately after the database is opened

HIGH MEDIUM LOW NONE (default)

– Object only populated after they are scanned for the first time, if space available.

Controlled by the PRIORITY sub-clause of the INMEMORY clause

SQL> ALTER TABLE customers INMEMORY PRIORITY HIGH;


In-Memory Compression Levels

NO MEMCOMPRESS… Data is populated without any compression

MEMCOMPRESSION FOR DML … Minimal compression optimized for DML performance

MEMCOMPRESSION FOR QUERY LOW … Optimized for query performance (default)

MEMCOMPRESSION FOR QUERY HIGH… Optimized for query performance as well as space saving

MEMCOMPRESSION FOR CAPACITY LOW … Balanced with a greater bias towards as space saving

MEMCOMPRESSION FOR CAPACITY HIGH … Optimized for space saving

Controlled by the MEMCOMPRESS sub-clause of INMEMORY clause


In-Memory Compression LevelsControlled by the MEMCOMPRESS sub-clause of INMEMORY clause

SQL> ALTER TABLE customers INMEMORY 2 MEMCOMPRESSION NO

COMPRESSION;

SQL> ALTER TABLE customers INMEMORY 2 MEMCOMPRESSION FOR CAPACITY

LOW;


In-Memory Compression Levels

Use DBMS_COMPRESSION

Applies MEMCOMPRESS to sample set of data from a table

Returns estimated compression ratio

Controlled by the MEMCOMPRESS sub-clause of INMEMORY clause


In-Memory Column Store for RAC

Each node in RAC have IM Column Store– Same size recommended– Object by default distributed across all nodes

DISTRIBUTE BY ROWID RANGE DISTRIBUTE BY PARTITION DISTRIBUTE BY SUBPARTITION

– Consists of 1 IMCU objects distribute only one node

Populate same object to IM Column Store on

every nodes– Supported only Engineered Systems – EXADATA– Using DUPLICATE clause

SQL> ALTER TABLE orders INMEMORY 2 DISTRIBUTE BY PARTITION;

SQL> ALTER TABLE orders INMEMORY 2 DUPLICATE ALL;


How Does Database In-Memory Improve Performance?


Querying the In-Memory Column Store

Compressed Columnar Storage SIMD Vector Processing In-Memory Storage Indexes In-Memory Joins and Aggregations


Compressed Columnar Storage

Compressed Column Units allows an analytic query scan only data within the required column


The column format used in the IM column store has been specifically designed to maximize the number of column entries that can be loaded into the vector registers on the CPU and evaluated in a single CPU instruction

Each CPU core scans local in-memory columns Scans use super fast SIMD vector instructions

– Originally designed for graphics & science

Billions of rows/sec scan rate per CPU core – Row format is millions/sec

SIMD vector processing allows a set of column values to be evaluated together in a single CPU instruction

SIMD Vector Processing


In-Memory Storage Indexes

Each column is the made up of multiple column units

Min / max value is recorded for each column unit in a storage index

Storage index provides partition pruning like performance for ALL queries


In-Memory Joins

Bloom filters enable joins to be converted into fast column scans

Tried and true technology originally released in 10g

Same technique used to offload joins on Exadata


In-Memory JoinsExample

SQL> SELECT * 2 FROM customer c, 3 orders o 4 WHERE c.id = o.customer_id


In-Memory Aggregations

Without need to support objects such as indexes, summary tables and materialized views

New SQL Execution Operations– KEY VECTOR and VECTOR GROUP BY

Indicate plan is a vector transformation plan

Vector transformation plan designed for– Optimize queries involving aggregation and joins large

fact and multiple small dimension tables

– working with Star Queries


In-Memory Aggregations

Vector Transformation Plan supports – Aggregation operators :

SUM, AVERAGE, MIN, MAX, STD and VARIANCE COUNT DISTINCT operations not supported by VECTOR GROUP BY

– The grouping syntax used in query is GROUP BY GROUPING SETS, GROUP BY ROLLUP not currently supported

– All joins must be equijoins Multiple columns of dimension table join the fact table with same join type

and same data type (for best performance, not be wrapped in a fuction )


Vector Transformation Plan

SQL> SELECT t.calendar_year, 2 p.prod_category, 3 SUM(quantity_sold) 4 FROM times t, 5 products p, 6 sales f 7 WHERE t.time_id = f.time_id 8 AND p.prod_id = f.prod_id 9 GROUP BY t.calendar_year, 10 p.prod_category;

Example


What’scoming with Oracle Database 12.2?


What is coming with Oracle Database 12.2 ?

Starting in Oracle Database 12c Release 2 (12.2), can increase INMEMORY_SIZE size dynamically by using ALTER SYSTEM.

In-Memory Expressions (IM expressions)– IM expressions populate the results of frequently evaluated query expressions into the In-Memory

Column Store. A candidate for an IM expression might be (monthly_sales*12)/52.

In-Memory virtual columns (IM virtual columns)– IM virtual columns enable the IM column store to materialized some or all virtual columns on a table.

Active Data Guard will Support In-Memory

In-Memory Enhancements


Additional Information

• Oracle Database 12c Release 12.1.0.2 Documentation• Oracle Database In-Memory White Paper • Oracle Database In-Memory Aggregation Paper • When to use Oracle Database In-Memory


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