1. Microsoft SQL Server 2014 for Oracle DBAs Module 3
11: Monitoring and performance tuning
Microsoft SQL Server 2014 for Oracle DBAs Module 3
Database architecture

2. Logging and data dictionary
Module Overview
4: Database architecture
Logging and data dictionary
Note: The spelling of datafiles and data files above is intentional. Within Oracle, it is spelled as a single word as DATAFILE to denote a syntax element. (Note that there is also a view called DBA_DATA_FILES, so both forms are used in Oracle.) For SQL Server, it is two words and not used in syntax.

3. Lesson 1: Schema and data storage
4: Database architecture
Managing extents and pages

4. Schema and data structures (objects)
4: Database architecture
Schema – a collection of objects owned by a database user
Schemas in SQL Server provide logical separation of objects, similar to Oracle’s schema
Comparison of Core Schema and Data Structures (Objects)
Table
Index
View
Synonym
Sequence
Procedure
Function
Package
Queue in streams Advanced Queuing
Object Type
XML DB
Stored Procedure
N/A
Service Broker Queue
Type
XML Schema Collection & Data type

5. Temporary Tablespace Groups
Storage architecture
4: Database architecture
Database storage architecture includes physical and logical structures
Physical structures are data files, log files, and operating system blocks
Logical structures are subdivisions of data files used to manage storage space
Data File
Tablespace
Temporary Tablespace Groups
Segment
Extent
Heap/Index
Filegroup
Physical
Logical
Oracle
SQL Server
Blocks
Pages

6. Data blocks, extents, and segments
4: Database architecture
Structure
Oracle
SQL Server
Smallest unit of
Logical storage
Block size
Storage allocation
Extent size
Segment
Block
Variable
Any logical structure that is allocated storage
Page
8 KB fixed
Performed in multiple pages; are ‘extents’
64 KB fixed
No equivalent structure

7. 40074A
Storage allocation
4: Database architecture
Fundamental difference in storage allocation between Oracle and SQL Server 2k
block
6 x 2K = 12k
Extent
12K x 16K = 28K
Segment
(Table/Index)
8x 2K = 16k 8k
64K x 64K = 128K
Heap/Index
Oracle
SQL Server
8x 8K = 64k
 What does the size difference mean? Optimized for each of the database engine types

8. Managing extents and pages
4: Database architecture
File header extent
Extents in SQL Server
GAMs and SGAMs
File header
Page 0
SGAM
Page 3 …
GAM
Page 2
PFS
Page 1
table2
index1
index2
table3
index3
Mixed extent
table1
Uniform extent
Current use of extent
GAM bit
setting
SGAM bit
Free, not being used
Uniform, extent, or full mixed extent 1

9. Lesson 2: Tablespaces and datafiles
4: Database architecture
Demonstration: Viewing an instance’s system databases

10. Oracle tablespaces and datafiles
4: Database architecture
Oracle and SQL Server store data in datafiles
The largest logical storage structure in Oracle is a tablespace
The largest logical storage structure in SQL Server is a filegroup
Tablespaces/filegroups are used to group application objects
Tablespaces/filegroups optimize administration of datafiles

11. Three file types supported by SQL Server: Primary data files
SQL Server data files
4: Database architecture
Three file types supported by SQL Server:
Primary data files
Secondary data files
Log data files
Database: MyDB
Primary filegroup
c:\Program Files\Microsoft SQL Server\MSSWL\Data\MyDB_Prm.mdf
Log file
c:\Program Files\Microsoft SQL Server\MSSWL\Data\MyDB.Idf
MyDB_FG1 filegroup
c:\Program Files\Microsoft SQL Server\MSSWL\Data\MyDB._FG1_1.ndf
c:\Program Files\Microsoft SQL Server\MSSWL\Data\MyDB._FG1_2.ndf
4 MB
1 MB

12. Mapping of tablespaces and filegroups
4: Database architecture
Oracle database
instance
Data File
Tablespace Group
Redo Log
System Tablespace
SysAux Tablespace
Temporary Tablespace
BigFile Tablespace
User Data Tablespace
User Index Tablespace
Undo Tablespace
Redo Log Files
SQL Server
User Database
Log Files
Master DB
Resource DB
Temp DB
Model DB
MSDB
User DB
Data FG
Index FG
Log File(s)

13. Demonstration: Viewing an instance’s system databases
4: Database architecture
In this demonstration you will see how to:
Connect to an instance
Review system databases
Review application or user databases
Demonstration Steps
Open SQL Server Management Studio and connect to an instance.
Click Start → All Programs → Microsoft SQL Server 2014 → SQL Server Management Studio.
Connect to the instance INST01 using Windows authentication.
In the Object Explorer, expand the INST01 instance node, expand Databases, and then expand the System Databases folder. Below is a description of the system databases.
Master: Composed of system tables that keep track of the server installation as a whole and all databases that are subsequently created. The master database has system catalogs containing information about disk space, file allocations, usage, system-wide configuration settings, login accounts, the existence of other databases, and the existence of other SQL Servers.
Model: The model database is a template database. Every time a new database is created, SQL Server makes a copy of the model to form the basis of the new database.
TempDB: The temporary database, TempDB, is a workspace. Every time SQL Server is restarted, the TempDB is recreated and not recovered. It is used for temporary tables created explicitly by users, for worktables to hold intermediate results created internally by SQL Server for query processing and sorting, and for materialization of static cursors and the keys of key set cursors.
MSDB: The MSDB database is used by the SQL Server Agent service to perform scheduled activities such as backups and replication tasks.In the Databases folder, note that the user databases are shown. If Reporting Services were installed on this server, two reporting databases would be installed here:
ReportServer
ReportServerTempDB
Note the installed sample databases:
AdventureWorks2012: This is the sample OLTP database.
AdventureWorksDW2012: This is the sample data warehouse database.
(More notes on the next slide)

14. Lesson 3: Logging and data dictionary
4: Database architecture
Demonstration: View the data dictionary

15. 40074A
Logging model
4: Database architecture
Oracle uses online redo logs to record changes made to the database by transactions and undo segments to capture the ‘before image’ of data
SQL Server implements both of these functions using transaction logs. Each transaction record contains the undo and redo image of the transaction
 In-Memory OLTP – doesn’t use write ahead logging to disk – thus improving performance MVCC
Virtual log 1
Virtual log 2
Virtual log 3
Virtual log 4
Virtual log 5
Truncated
Unused
Start of logical log
MinLSN
Last checkpoint
End of logical log
Virtual Log 1
Virtual Log 2
Virtual Log 3
Virtual Log 4
Truncated
Start of logical log
MinLSN
Next to last checkpoint
Last checkpoint
End of logical log

16. 40074A
Data dictionary
4: Database architecture
In Oracle the data dictionary is stored under the SYS schema in the SYSTEM tablespace
In SQL Server the data dictionary consists of:
Catalog View—the best way to access system metadata
Backward Compatibility Views—All system tables from previous releases are provided as backward compatibility views
Dynamic Management Views—to view the current state of the SQL Server system. Provide real-time snapshots of internal memory structures indicating the server state.
INFORMATION_SCHEMA views—SQL-99 method to view system metadata
SQL Server’s Resource database contains the metadata for system stored procedures

17. Demonstration: View the data dictionary
4: Database architecture
In this demonstration you will learn how to:
View the dictionary with object explorer
View the data dictionary with catalog views
View the data dictionary within a database
View the data dictionary via system stored procedures
Demonstration Steps
Click any instance from the Object Explorer. If you are not sure which one to choose, select INST01.
Click Databases → System Databases → Master → Views → System Views to see catalog views.
To see similar catalog views for a user database other than the system databases, select and expand the Databases folder.
To view the system-stored procedures, go to Databases → System Databases → Master → Programmability.
Open the New Query Editor.
Right-click the Context menu. Notice the connection dialog. Navigate to the Change Connection dialog. Notice that you can change the context of the query by connecting it to another server.
Release the mouse button.
Look at the bottom right window of the query. Notice your identity and database connection properties.
Connect to the SQL Server INST01 instance and select the master database.
Use the following query to extract the system tables:
Select name from sys.objects where type = 'S'
Use the following query to extract views:
Select name from sys.objects where type = 'V'
You also can view properties of stored procedures. To show the names of stored procedures, execute the code below:
Select name from sys.objects where type = 'P'Open the Query Editor and select the Adventureworks2012 database.
To find column information for the Shift table in the AdventureWorks2012 database, execute the
(More notes on the next slide)

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