SAP DB2 on DB2 Administration
April 18, 2017 | Author: Bhaskar Sharma | Category: N/A
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Download SAP DB2 on DB2 Administration...
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DB2 Administration, Monitoring, Tuning in SAP Environment
Agenda Table space management Table space concepts and administration Automatic Storage Database administration Log file management Backup / Restore / Recovery Table maintenance (runstats, reorg) DB2 Parameters Problem determination Monitoring and performance tuning Memory Management and STMM Monitoring Tools DB2 Parallelism DB2 / SAP integration SAP DB2 file system and table space layout SAP DB2 Cockpit ...
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DB2 Table Space Management
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Table Spaces – Overview DB2 table spaces store data and indexes A table space consist of one or more containers. A container can be a Directory File Device There are two types of table spaces: System managed space (SMS): The corresponding containers are directories. The operating system's file manager controls the storage space. Database managed space (DMS): The corresponding containers are files or devices. The database manager controls the storage space. 15 February, 2012
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Table Spaces And Containers Database objects
Physical storage objects
System DB2 Instance Database SMS Table Space • Tables • Indexes • Long data DMS Table Space • Tables • Indexes • Long data
Containers
Directory 1
... Directory N
Containers
File 1
... File N
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Table Spaces – Usage types Depending on the usage type, the following table space categories can be distinguished: Regular table space Stores all permanent data Uses 4 byte RIDs Large table space Always of type DMS. V8: For example used to LONG VARCHAR and LOB data. V9: Stores all permanent data. Uses 6 byte RIDs System temporary table space Stores temporary tables, i.e. work areas used by the database manager to perform operations such as sorts or joins.
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Characteristics of DMS Table Spaces Table space containers are either pre-allocated files (DMS file containers) or raw devices (DMS device containers) Containers can be added, removed, or resized The space allocation unit is an extent Extents are striped across the containers of a table space in a round-robin fashion. An extent consists of two or more pages
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Characteristics of SMS Table Spaces
SMS table spaces use the file system manager of the operating system to manage the space where data is stored Containers cannot be added after the table space has been created. Table space capacity can be increased by enlarging underlying operating system file systems The data in the table space is striped by extent across the containers Database objects are stored in different files in the corresponding directories. For example SQL*.DAT files store information about tables (the asterisk * is replaced by a unique set of digits that identifies the table) Additional files may exist for a table (depending on data types, e.g. LONG fields and corresponding indexes that belong to the table).
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Storage of Table and Index Data Table data and corresponding indexes of a single table can be stored in different tablespaces: Data can be stored in a DMS or SMS table space Indexes can be stored separately from the data in a DMS or SMS table space. Large data types (e.g. LONG VARCHAR) can be stored in a separate DMS LARGE table space.
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Table Space Page Sizes Table spaces can be created with the following page sizes: 4 KB 8 KB 16 KB 32 KB A dedicated buffer pool is required for each page size which is used by the table spaces. The default page size is 4 KB. SAP uses uniform page size of 16K with Basis >= 6.40 Only one buffer pool required. Increased table space size limits due to larger page size
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Page Sizes And Table Space Limits (V8) 4KB
64GB 128GB
8KB
256GB
16KB
512GB
32KB Table space size
Page size 16M
255
4x109 Rows
Row ID (RID) 4 Bytes For tables in all table spaces (regular, temporary, DMS, SMS) 15 February, 2012
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Page Sizes And Table Space Limits (V9) 4KB
2TB 4TB
8KB
8TB
16KB
16TB
32KB Table space size
Page size 512M
~2K
1.1x1012 Rows
Row ID (RID) 6 Bytes For tables in LARGE table spaces (DMS only) Also all SYSTEM and USER temporary table spaces 15 February, 2012
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Table Space Statements
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Table Space Statements The CREATE TABLESPACE statement defines a new table space within the database, assigns containers to the table space, and records the table space definition and attributes in the catalog The ALTER TABLESPACE statement is used to modify an existing table space Required privileges for the user who executed these statements are SYSCTRL or SYSADM authority
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CREATE TABLESPACE – DMS Example CREATE LARGE TABLESPACE AKS#BTAB PAGESIZE 16K MANAGED BY DATABASE USING (file '/db2/AKS/sapdata1/NODE0000/AKS#BTAB.container001' 1000 M) EXTENTSIZE 2 FILE SYSTEM CACHING AUTORESIZE YES INCREASESIZE 200 M DROPPED TABLE RECOVERY OFF
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CREATE TABLESPACE – SMS Example CREATE TEMPORARY TABLESPACE SYSTOOLSTMPSPACE IN DATABASE PARTITION GROUP IBMCATGROUP PAGESIZE 16K MANAGED BY SYSTEM USING ('/db2/V91/saptemp1/NODE0000/temp16/SYSTOOLSTMPSPAC E.container000') EXTENTSIZE 2 PREFETCHSIZE AUTOMATIC BUFFERPOOL BP_STD_16K DROPPED TABLE RECOVERY OFF
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Getting Information About Table Spaces DB2 CLP commands: db2 list tablespaces [show detail] db2 list tablespace containers for [show detail] DB2 snapshot: db2 get snapshot for tablespaces on SQL table functions: Example: db2 "select PAGE_SIZE, EXTENT_SIZE, PREFETCH_SIZE from table(SNAPSHOT_TBS_CONT('sample',0) as o" Command db2pd: db2pd –db –tablespaces 15 February, 2012
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Example – LIST TABLESPACES SHOW DETAIL Tablespaces for Current Database Tablespace ID Name Type Contents State Detailed explanation: Normal Total pages Useable pages Used pages Free pages High water mark (pages) Page size (bytes) Extent size (pages) Prefetch size (pages) Number of containers […] 15 February, 2012
= = = = =
0 SYSCATSPACE Database managed space Any data 0x0000
= = = = = = = = =
166400 166398 51408 114990 51408 4096 2 2 1
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Example – LIST TABLESPACES SHOW DETAIL […] Tablespace ID Name Type Contents State Detailed explanation: Normal Total pages Useable pages Used pages Free pages High water mark (pages) Page size (bytes) Extent size (pages) Prefetch size (pages) Number of containers
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= = = = =
1 SYSTOOLSPACE System managed space Any data 0x0000
= = = = = = = = =
12761 12761 12761 Not applicable Not applicable 4096 32 32 1
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Example – LIST TABLESPACE CONTAINERS Output on Windows using DMS file containers: db2 list tablespace containers for 5 Tablespaces Containers for Tablespace 5 Container ID = 0 Name = c:\DB2\data.cont1 Type = Disk
Output on UNIX using device containers: db2 list tablespace containers for 5 Tablespaces Containers for Tablespace 5 Container ID = 0 Name = /dev/rdata1 Type = Disk
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Changing the Size of a Table Space
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Changing the Size of a Table Space
The ALTER TABLESPACE statement lets you add a container to an existing DMS table space or extend a container to increase its storage capacity
You can not ALTER a SMS table space – instead you need to increase the size of the underlying file system
Data will be striped evenly across all of the table space containers until the individual containers fill up
Adding a container to a DMS table space which is smaller than existing containers may result in reduced performance If some of the smaller containers become full, this may result in reduced I/O parallelism (e.g. during data prefetching).
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Rebalancing
When new containers are added to a table space or existing containers are extended, a rebalance of the table space data may occur
The process of rebalancing is done in an attempt to keep data evenly distributed across all containers of the table space.
Access to the table space is not restricted during rebalancing but there can be a significant impact on performance
To avoid rebalancing you may extend all existing containers by the same size or add new containers in a new stripe set
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Rebalancing (Cont’d) A rebalancing is done asynchronously after the following ALTER TABLESPACE options: ADD will result in forward rebalancing DROP will result in reverse rebalancing To avoid rebalancing choose the following ALTER TABLESPACE options: RESIZE / EXTEND / REDUCE ALL CONTAINERS BEGIN NEW STRIPE SET to create a new stripe set
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ALTER TABLESPACE – Examples To add a new DMS container file to table space PSAPBTABD: ALTER TABLESPACE PSAPBTABD ADD (FILE '/db2/P01/sapdata5/PSAPBTABD.container005' 25000) To extend all table space containers of table space ICP#STABD by 10000 pages: ALTER TABLESPACE ICP#STABD EXTEND (ALL 10000) To resize (e.g. shrink) all table space containers for table space Y9C#POOLI to a new size of 1000 Megabytes: ALTER TABLESPACE Y9C#POOLI RESIZE (ALL 1000) To drop a DMS container from table space SYSCATSPACE: ALTER TABLESPACE SYSCATSPACE DROP (FILE '/db2/P01/sapdata5/SYSCATSPACE.container005') 15 February, 2012
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ALTER TABLESPACE – Examples (Cont’d) To change the buffer pool for table space PSAPBTABD: ALTER TABLESPACE PSAPBTABD BUFFERPOOL SAPBP_32K To change the prefetch size of table space Y9C#POOLI: ALTER TABLESPACE Y9C#POOLI PREFETCHSIZE AUTOMATIC To turn off file system caching for table space ICP#STABD: ALTER TABLESPACE ICP#STABD NO FILE SYSTEM CACHING To turn off dropped table recovery for table space APPL1: ALTER TABLESPACE APPL1 DROPPED TABLE RECOVERY OFF
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Automatic Resizing Of DMS Table Spaces DMS table spaces have a feature called "auto-resize“ (available with DB2 V8.2.2). DB2 can automatically enlarge DMS table space for which the autoresize attribute is activated. SMS table spaces have similar capabilities for growing automatically but the term "auto-resize" is used exclusively for DMS Two additional attributes, MAXSIZE and INCREASESIZE, are associated with auto-resize table spaces: The MAXSIZE (Maximum Size) clause defines the maximum size for the table space. The INCREASESIZE clause defines the amount of space which is automatically added when the table space becomes full.
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How to enable Auto-resize Creating a DMS tablespace and enabling the auto-resize feature: CREATE TABLESPACE DMS1 MANAGED BY DATABASE USING (FILE '/db2data/DMS1' 10 M) AUTORESIZE YES You can also enable or disable the auto-resize feature after a DMS table space has been created by using the ALTER TABLESPACE statement: ALTER TABLESPACE NUC#BTABD AUTORESIZE YES ALTER TABLESPACE NUC#BTABD AUTORESIZE NO
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Auto-resize – Monitoring (1/2) Automatic resizing for DMS table spaces is displayed as part of the table space monitor snapshot output: Tablespace name
= NUC#USER1D
[…] Using automatic storage
= No
Auto-resize enabled
= Yes
File system caching
= Yes
[…] Current tablespace size (bytes)
= 10485760
Maximum tablespace size (bytes)
= NONE
Increase size (bytes)
= AUTOMATIC
Time of last successful resize
= 05/18/2005 16:48:51.474454
Last resize attempt failed
= No
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Auto-resize – Monitoring (2/2) The db2pd command does also provide information about the automatic resizing of DMS tablespaces db2pd –db -tab[lespaces] Tablespace Autoresize Statistics: Address Id AS AR Auto LastResize LRF 0x00000004C3957960 0 No Yes No 03/22/2006 16:19:51.434751 No 0x00000004C395F960 2 No Yes No None No 0x00000004C3962920 3 No Yes No None No 0x00000004C3962FA0 4 No Yes No None No 0x00000004C396A0A0 5 No Yes No 04/04/2006 07:42:36.268448 No 0x00000004C396B1C0 6 No Yes No None No 0x00000004C396B840 7 No Yes No 04/05/2006 15:41:02.263465 No
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InitSize
IncSize
IIP MaxSize
0
-4096
No
None
0
-16384
No
None
0
-4096
No
None
0
-16384
No
None
0
-16384
No
None
0
-16384
No
None
0
-16384
No
None
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Use of Concurrent/Direct IO Without file system caching DB2 always attempts to use concurrent I/O (CIO) wherever possible: In cases where CIO is not supported (for example, if JFS is used), direct I/O (DIO) will be used instead. NFS file systems usually do not support DIO/CIO (will result in warning messages in db2diag.log) The settings for the table spaces can be retrieved with the GET SNAPSHOT FOR TABLESPACES command Alternatively, use db2pd –tab … (search for column FSC)
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Automatic Storage
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Automatic Storage – Overview If automatic storage is enabled for a database the container management is completely handled by DB2. Automatic storage databases have a set of one or more storage paths associated with them. Example: CREATE DATABASE myDB ON /db2/ABC1, /db2/ABC2 If a table space is defined as "managed by automatic storage" DB2 performs the following tasks automatically: Initial creation of table space containers in the given storage paths. Extension of table space containers if required. Adding table space containers if required.
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Automatic Storage – Overview (Cont’d) A database can only be enabled for automatic storage when it is first created You cannot enable automatic storage for a database that was not originally defined to use it Similarly, you cannot disable automatic storage for a database that was originally designed to use it. New storage paths can be added to the database later on. Example: ALTER DATABASE myDB ADD STORAGE ON /db2/ABC3
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Automatic Storage – Database Path and Storage Path The database path is the path where DB2 stores control files for the database. It is specified by the DBPATH ON clause in the CREATE DATABASE command. The storage path is the path where DB2 creates automatic storage table space containers. It is specified by the ON clause. Multiple storage paths can be specified. If the DBPATH ON clause is not specified, the first path listed in the ON clause indicates the database path (in addition to it being a storage path).
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Automatic Storage Examples CREATE DATABASE ABC ON /db2/ABC Database is not automatic storage enabled (pre V8.2.2 default) Attention: With V9 the database is automatic storage enabled per default CREATE DATABASE ABC ON /db2/ABC1, /db2/ABC2 Database is automatic storage enabled Database Path: /db2/ABC1 Storage Paths: /db2/ABC1, /db2/ABC2 CREATE DATABASE ABC ON /db2/ABC/sapdata1, /db2/ABC/sapdata2 DBPATH ON /db2/ABC Database is automatic storage enabled Database Path: /db2/ABC Storage Path: /db2/ABC/sapdata1, /db2/ABC/sapdata2 15 February, 2012
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Automatic Storage & SAPinst Automatic storage is the default setup for all SAP NetWeaver 2004s (and higher) systems
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Automatic Storage – Table Spaces (1/3) Automatic storage table spaces are an extension of the existing SMS and DMS table space types: If the table space being created is a REGULAR or LARGE table space, it uses DMS file containers If the table space being created is a TEMPORARY table space, it uses SMS directory containers To create an automatic storage table space: CREATE LARGE TABLESPACE myTS MANGED BY AUTOMATIC STORAGE
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Automatic Storage – Table Spaces (2/3) The names associated with the automatic storage containers have the following format: / / NODE0000/ / Table space ID T#######/ C#######. Container ID EXT(ension) can be: CAT (system catalog), TMP (system temporary), UTM (user temporary), USR (user regular), LRG (user large) 15 February, 2012
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Automatic Storage – Table Spaces (3/3) Example paths used for automatic storage in a NW04S system: Tablespace Containers for Tablespace 0 Container ID = 0 Name = /db2/SAT/sapdata1/db2sat/NODE0000/SAT/T0000000/C0000000.CAT Type = File Tablespace Containers for Tablespace 3
Temporary table spaces are NOT using automatic storage in SAP environments
Container ID = 0 Name = /db2/SAT/saptemp1/NODE0000/temp16/PSAPTEMP16.container000 Type = Path Tablespace Containers for Tablespace 6 Container ID = 0 Name = /db2/SAT/sapdata1/db2sat/NODE0000/SAT/T0000006/C0000000.USR Type = File 15 February, 2012
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Automatic Storage – Monitoring Storage Paths A database snapshot includes the list of storage paths associated with the database: db2 get snapshot for db on Number of automatic storage paths Automatic storage path Automatic storage path
= 2 = /db2/SXI/sapdata1 = /db2/SXI/sapdata2
In addition you can use db2pd command: db2pd –db –sto[ragepaths] Database Storage Paths: Number of Storage Paths
2
Address PathName 0x237E0590 /db2/SXI/sapdata1 0x24260D90 /db2/SXI/sapdata2 15 February, 2012
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DB2 Database Administration
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DB2 Database Administration Log file management Backup / Restore / Recovery Table maintenance (runstats, reorg) DB2 Parameters Problem determination
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DB2 Logging – Overview Log Buffer
Online Active Log
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db2agent
db2pclnr
db2loggw
synchronous write on COMMIT/ ROLLBACK every second when log buffer is full
Buffer Pool
asynchronous write chngpgs_threshold is reached SOFTMAX has been reached No BP pages are available during insert/update
Database Files 44
DB2 Logging – Circular Logging 1
Primary Logfiles
n
3
2
1
Secondary log files – allocated if necessary / defined
n
Default configuration after database creation Not supported for production environments (no online backups possible – no point-in-time recovery) 15 February, 2012
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DB2 Logging – Archive Logging db2uext2 – located in $HOME/sqllib/adm (not provided by IBM)
DB2 archives log file (calls db2uext2 in V8.1)
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13
Active: Contains information for noncommitted or nonexternalized transactions
14
Offline archive: Archived from active log subdirectory to disk/ tape/ TSM … 15 February, 2012
Online archive: Contains information for committed and externalized transactions Stored in the active log directory
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DB2 Log File Management DB2 Engine
TSM
Vendor
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Overflow Log
History File
Disk
db2tapemgr
db2tapemgr
Failarch Path
Mirror Log
db2logmgr
Log Dir
Beginning with DB2 Version 8.2 log file management is part of the DB2 engine Supports disk, TSM, vendor library, user exit (db2uext2) Log file location information is stored in history file Configuration via DB configuration parameters
Tape
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Logging Configuration Parameters (1/4) Log archive method 1 (LOGARCHMETH1), log archive method 2 (LOGARCHMETH2) These parameters cause the database manager to archive log files to a location that is not the active log path If both of these parameters are specified, each log file is archived twice (e.g. to different media types) The parameter value includes a media type and, in some cases, a target field. Use a colon (:) to separate the values
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Logging Configuration Parameters (2/4) Valid values for LOGARCHMETH1and LOGARCHMETH2 are: DISK: Log files are archived to disk (e.g. log_archive directory) TSM: Tivoli Storage Manager is used for archiving. VENDOR: Vendor library is invoked. DB2 provides a vendor API for the log file management USEREXIT Program db2uext is invoked (not part of DB2 product) LOGRETAIN Log files are not archived automatically, i.e. inactive log files need to be archieved manually. OFF 15 February, 2012
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Logging Configuration Parameters (3/4) Log archive options 1 (LOGARCHOPT1), log archive options 2 (LOGARCHOPT2) Specifies a string which is passed on to the TSM server or vendor APIs Archive retry delay (ARCHRETRYDELAY) Specifies the amount of time (in seconds) to wait between attempts to archive log files after the previous attempt fails The default value is 20 seconds Failover archive path (FAILARCHPATH) Specifies an alternate directory for the archive log files if the log archive method specified fails
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Logging Configuration Parameters (4/4) Log file size (LOGFILSIZ) Size of log files (in 4 KB) Number of primary log files (LOGPRIMARY) Specifies the number of primary log files to be pre-allocated when starting the database Number of secondary log files (LOGSECOND) Specifies the number of secondary log files that are created and used for recovery log files (only as needed)
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Logging Configuration – Examples To turn on direct archiving of log files to Tivoli Data Protector on AIX use the following command: db2 update database cfg for QHA using LOGARCHMETH1 VENDOR:/usr/tivoli/tsm/tdp_r3/db264/libtdpdb264.a db2 update database cfg for QHA using LOGARCHOPT1 /db2/db2qha/tdpr3/vendor.env To turn on archiving of log files to disk use the following command: db2 update database cfg for TST using LOGARCHMETH1 DISK:/db2/TST/log_archive
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LIST HISTORY COMMAND The LIST HISTORY command lists entries in the recovery history file To see entries regarding archive log operations the archived logs issue: db2 list history ARCHIVE LOG all for database
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Closing Active Log File On Demand A DB2 command allows users to close and archive the active log at any time Allows users to acquire a complete set of log files up to the point in time at which the command is executed Only useable on recoverable databases (i.e. database is defined to use archival logging) Command: db2 archive log for database
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Log Disk Full Vs. Log File Full Two common problems that may occur regarding log space are: SQL0964C: Transaction log full Long running transactions are taking up all active log space of the database Solution: force the oldest transaction (reported in db2diag.log) or increase the number of secondary log files SQL0968C: Log disk full DB2 cannot create new log files in the log directory because the file system is full Usually caused by problems with the archiving of log files check the db2uext2, connection to TSM etc.
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DB2 Backup
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DB2 Backup – Overview The DB2 backup and restore utilities are built as part of the DB2 engine Image(s) are logical format Not file based Provides more flexibility for restore, e.g. change disk layout on restore Amount of resources used under complete control of the caller The more resources allocated the faster the utilities will run
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DB2 Backup – Overview (Cont’d) Backup Media available for DB2 Local devices, e.g. tape, disk, named pipe Tivoli Storage Server (TSM) XBSA compliant clients, e.g. Legato NetWorker Vendor supplied DB2 library, e.g. Veritas NetBackup DB2 Backup image contains table data as well as database configuration and history files
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DB2 Backup – Command Syntax (excerpt) BACKUP DATABASE database-alias [USER username [USING password]] [TABLESPACE (tblspace-name [ {,tblspace-name} ... ])] [ONLINE] [INCREMENTAL [DELTA]] [USE {TSM | XBSA} [OPEN num-sess SESSIONS] [OPTIONS {optionsstring | options-filename}] | TO dir/dev [ {,dir/dev} ... ] | LOAD lib-name [OPEN num-sess SESSIONS] [OPTIONS {optionsstring | options-filename}]] [WITH num-buff BUFFERS] [BUFFER buffer-size] [PARALLELISM n] [COMPRESS [COMPRLIB lib-name [EXCLUDE]] [COMPROPTS optionsstring]] [UTIL_IMPACT_PRIORITY [priority]] [{INCLUDE | EXCLUDE} LOGS]
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DB2 Backup Command – Examples Example command for an offline backup of database SI1 using Legato NetWorker Module on Solaris with 2 sessions: BACKUP DB SI1 LOAD /usr/lib/libnsrdb2.so OPEN 2 SESSIONS Example command for an online backup of database C11 to disk (directory c:\db2\backup): DB2 BACKUP DB C11 ONLINE TO c:\db2\backup Example command for an online backup of two table spaces of database QH2 to Tivoli Storage Manager (TSM): BACKUP DB QH2 TABLESPACE (PSAPPOOLD, PSAPPOOLI) ONLINE USE TSM COMPRESS
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DB2 History File The DB2 history file contains a record of recovery and administrative events Recovery events include backup, restore rollforward and archive log operations Additional logged events include create, alter, drop, or rename table space, reorganize table, drop table, and load Use the LIST HISTORY command to query the history file, for example to see all backups for database QPT, issue: db2 list history backup all for QPT
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LIST HISTORY BACKUP – Example Op Obj Timestamp+Sequence Type Dev Earliest Log Current Log Backup ID -- --- ------------------ ---- --- ------------ ------------ -------------N O S0019095.LOG S0019100.LOG B D 20060110182712001 ---------------------------------------------------------------------------Contains 7 tablespace(s):
Log file sequence required for 00001 SYSCATSPACE Operation: Backup 00002 APPL1 rollforward of ONLINE backup 00003 APPL 00004 APPL2 00005 DFACT 00006 APPL0 00007 SYSTOOLSPACE ---------------------------------------------------------------------------Comment: DB2 BACKUP QPT ONLINE Start Time: 20060110182712 End Time: 20060111013737 Status: A ---------------------------------------------------------------------------EID: 32069 Location: /usr/lib/libnsrdb2.so Location: here Legato Op Obj Timestamp+Sequence Type Dev Earliest Log Current Log Backup ID -- --- ------------------ ---- --- ------------ ------------ -------------B D 20060110182712002 N O S0019095.LOG S0019100.LOG ---------------------------------------------------------------------------Contains 7 tablespace(s): […] 15 February, 2012
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DB2 Restore
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DB2 Restore – Command Syntax (excerpt) RESTORE DATABASE source-database-alias { restore-options | CONTINUE | ABORT } restore-options: [USER username [USING password]] [ TABLESPACE (tblspace-name [ {,tblspace-name} ... ]) [ONLINE] | HISTORY FILE [ONLINE] | LOGS [ONLINE] | COMPRESSION LIBRARY [ONLINE]] [USE {TSM | XBSA} [OPEN num-sess SESSIONS] [OPTIONS {options-string | options-filename}] | FROM dir/dev [{,dir/dev} ... ] | LOAD shared-lib [OPEN num-sess SESSIONS] [OPTIONS {options-string | options-filename}]] [TAKEN AT date-time] [TO target-directory] [INTO target-database-alias] [LOGTARGET directory] [NEWLOGPATH directory] [WITH num-buff BUFFERS] [BUFFER buffer-size] [REPLACE HISTORY FILE] [REPLACE EXISTING] [REDIRECT] [PARALLELISM n] [COMPRLIB lib-name] [COMPROPTS options-string] [WITHOUT ROLLING FORWARD] [WITHOUT PROMPTING]
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DB2 Restore Command – Example Example command for a database restore of database SI1 using Legato NetWorker Module on AIX: This command will replace the current SI1 database with the backup image taken at 05-05 2005 at 12:55:00 db2 "restore db si1 load /usr/lib/libnsrdb2.o open 2 sessions taken at 20050505125500 with 4 buffers buffer 2048 parallelism 2 replace existing without prompting"
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Cross-platform Restoration Windows 32-bit
AIX 32-bit
Windows 64-bit
Big-endian Unix backup images are compatible
AIX 64-bit
Solaris 32-bit
Solaris 64-bit
HP-UX 32-bit
HP-UX 64-bit
Linux 32-bit
Linux 64-bit
Supported by SAP for Heterogeneous System Copies 15 February, 2012
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Database Copy Using Backup/Restore & Pipes Source
Target Backup
Database
1. 2. 3. 4. 5. 6.
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Restore
Database
Update .rhosts mkfifo mkfifo rsh "dd if= bs=8k" | dd of= db2 restore db from into db2 backup db to
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DB2 Recovery
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DB2 Roll Forward Versus Restart Recovery Two types of DB2 recovery: Restart recovery (aka crash recovery) Performed automatically during database restart (if DB parameter AUTORESTART is set to ON) DB2 reruns all transactions that were performed previously but have not been written to disk The DB2 log control file header contains the log sequence number, which must be used as the starting point of the recovery Restore & roll forward recovery Manually (using RESTORE and ROLLFORWARD commands – or RECOVER) 15 February, 2012
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DB2 Rollforward – Command Syntax (excerpt) ROLLFORWARD DATABASE database-alias [USER username [USING password]] {[TO {isotime [USING LOCAL TIME] | END OF LOGS}] [AND COMPLETE]} | {COMPLETE | CANCEL | QUERY STATUS [USING LOCAL TIME]} [TABLESPACE (tblspace-name [ {,tblspace-name} ... ]) [ONLINE]] [OVERFLOW LOG PATH (log-directory)] [RECOVER DROPPED TABLE dropped-table-id TO export-directory]
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DB2 Rollforward Command – Examples To query the roll forward status of database A3M enter: db2 rollforward db A3M query status To roll forward database B20 to end of logs (without using the db2uext2 to recover log files) and open the database afterwards, enter: db2 rollforward db B20 to end of logs and complete To roll forward database BUD to 01-01-2006, 14:05 local time, enter: db2 rollforward db BUD to 2006-01-0114.05.00.000000 using local time The database will remain in rollforward pending state – to open database issue db2 rollforward db BUD complete
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Simplified Database Recovery – RECOVER The RECOVER DATABASE command combines the functionality of the RESTORE DATABASE and ROLLFORWARD DATABASE commands When you use this command, you specify the point-in-time to which you want the database recovered You do not need to indicate which database backup image must be restored or which log files are required to reach the specified point-in-time The RECOVER DATABASE command also supports recovery operations to the end of the log files
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RECOVER DATABASE – Command Syntax (excerpt) RECOVER DATABASE database-alias [TO {isotime [USING LOCAL TIME | USING GMT TIME] | END OF LOGS} ] [USER username [USING password]] [USING HISTORY FILE (history-file)] [OVERFLOW LOG PATH (log-directory)] [COMPRLIB lib-name] [COMPROPTS options-string]
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RECOVER DATABASE Command – Examples To use the latest backup image and rollforward to the end of logs using all default values: RECOVER DB XDM To recover the database to a point-in-time, issue the following command: RECOVER DB PLN TO 2005-08-31-04:00:00 The most recent image that can be used will be restored, and logs applied until the PIT is reached To recover a subset of partitions, issue: RECOVER DB J20 TO END OF LOGS ON DBPARTITIONNUMS(2 TO 4, 7, 9) A point-in-time RECOVER cannot be done in this case, the recover must be done to end-of-logs 15 February, 2012
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Monitoring Backup/Restore Operations
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LIST UTILITIES Command DB2 V8.2 introduces the LIST UTILITIES command It can be used to monitor DB2 utilities like: Backup Restore Crash recovery Load Rebalance The SHOW DETAIL option of the LIST UTILITY command provides information about the progress of the operation Alternatively you can use the db2pd command, for example: db2pd –uti[lities] [–repeat 10]
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LIST UTILITIES Command – Example
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DB2 9 – Backup And Restore Enhancements New table function to list all files in a database Used to automate support of split mirror backup/recovery Restartable Recovery Re-issuing RECOVER command will pick up where it left off Ability to change Point In Time in either direction Rebuild partial database Eliminate the need for FULL database restore Ability to rebuild the database from set of table space backup images Redirected Restore Script builder Build a redirected restore script from a backup image: ...REDIRECT GENERATE SCRIPT file-name...
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Table/Index Maintenance
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Data Maintenance Process – Overview RUNSTATS
REORGCHK
YES
REORG
Reorganization needed? NO
REBIND
RUNSTATS
FLUSH PACKAGE CACHE
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Overview of the REORGCHK Utility REORGCHK is a data maintenance utility which uses the current database statistics to check if database objects need to be reorganized. Optionally it can also update database statistics. It generates a report with multiple REORG indicators (e.g. F1,F2,F3) for tables and indexes. Tables or indexes that require a REORG are marked with an asterisk. C:\>db2 reorgchk current statistics on table user Table statistics: F1: 100 * OVERFLOW / CARD < 5 F2: 100 * (Effective Space Utilization of Data Pages) > 70 F3: 100 * (Required Pages / Total Pages) > 80 SCHEMA NAME CARD OV NP FP ACTBLK TSIZE F1 F2 F3 REORG ---------------------------------------------------------------------------------------OLAF CL_SCHED - --OLAF CLASS_LIST - --OLAF DEPARTMENT 9 0 1 1 549 0 - 100 --OLAF EMP_ACT 75 0 1 1 2850 0 - 100 --OLAF EMP_PHOTO 12 0 1 1 2028 0 - 100 --OLAF EMP_RESUME 8 0 1 1 984 0 - 100 --OLAF EMPLOYEE 32 0 2 2 2784 0 68 100 -*-
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REORGCHK Utility – Examples The following command checks table mytab based on the current table statistics: REORGCHK CURRENT STATISTICS ON TABLE mytab The following command updates the statistics and checks all tables created under the schema sapr3: REORGCHK UPDATE STATISTICS ON SCHEMA sapr3 The following command updates the statistics and checks all tables: REORGCHK UPDATE STATISTICS ON TABLE ALL
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Overview of the RUNSTATS Utility The RUNSTATS utility is used to collect statistics about the characteristics of a table and the associated indexes Characteristics include number of records (cardinality), number of pages, average record length, and much more. This information is used by the DB2 cost based optimizer to choose the optimal access plan The decisions the optimizer makes are heavily influenced by statistical information about the size of the database tables and indexes Therefore it is crucial to keep the database statistics up to date so that an efficient data access plan can be chosen!
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RUNSTATS Syntax (excerpt) RUNSTATS ON TABLE table-name [USE PROFILE | statistics-options] statistics-options: [table-object-options] [ALLOW {WRITE | READ} ACCESS] [table-sampling-options] [profile-options] [UTIL_IMPACT_PRIORITY [priority]] table-object-options: [{FOR index-clause | [column-stats-clause] [AND index-clause]}] table-sampling-options: [TABLESAMPLE {BERNOULLI | SYSTEM} (numeric-literal) [REPEATABLE (integer-literal)]] profile-options: [{SET PROFILE [NONE | ONLY] | UPDATE PROFILE [ONLY]}] [UTIL_IMPACT_PRIORITY [priority]]
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RUNSTATS Utility – Examples The following command collects statistics on the table db2user.employee; Read and write access is allowed while the statistics are being calculated: RUNSTATS ON TABLE db2user.employee ALLOW WRITE ACCESS The following command collects statistics on table db2user.employee and detailed statistics on all its indexes: RUNSTATS ON TABLE db2user.employee AND DETAILED INDEXES ALL
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Overview of the REORG Utility The REORG utility reorganizes tables and indexes and eliminates fragmented or empty pages. DB2 provides the option of performing the reorg online or offline You may also reorganize a table using an index: The order of RIDs in the index corresponds to the order of rows in the table after the reorg is completed. This helps to minimize I/O operations when accessing data using that index. Information about the table reorganization is available in the database history file in table snapshot output
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Online Table Reorganization Enhances database availability by allowing reorganization of tables while permitting read and write (online) table access Reorg can be started, paused, and resumed. Table is reorganized in a piece-wise fashion: Vacate: Frees pages by moving data to the back of the table Fill: Fills the freed pages V A C A T E P A G E R A N G E : M O V E & C L E A N to m a k e s p a c e
T IM E
fre e space
F IL L P A G E R A N G E : M O V E & C L E A N to fill s p a c e
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Index Reorganization REORG INDEXES supports two different functions: Rebuild: This is the default. Rebuilds the index data into unfragmented, physically contiguous pages. Cleanup only: Indexes will not be rebuild. Removes committed pseudo deleted keys and pseudo empty pages. Online index rebuild mechanism: Shadow index is created during normal transaction processing When index creation is complete, the old index is swapped out and the new index is made available Sufficient temporary space needs to be available to build the new index
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REORG Utility – Examples Reorg of table ATAB in-place while allowing write access db2 connect to db2 reorg table sapr3.atab inplace allow write access To start, pause, and resume an in-place reorg of the ATAB table use the following commands: db2 reorg table sapr3.atab inplace start db2 reorg table sapr3.atab inplace pause db2 reorg table sapr3.atab inplace allow read access notruncate table resume Query database history file: db2 list history reorg all for database
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Automating Database Maintenance DB2 allows the automation of certain database activities BACKUP database RUNSTATS on tables and indexes REORG of tables and indexes A Configure Automatic Maintenance wizard is available to specify Maintenance objectives Timeframe Automatic Runstats is used for all new (7.00 and higher) SAP systems Check SAP note # 860724 on how to enable older SAP releases for automatic runstats
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Automating Database Maintenance Parameters Enablement is controlled using the hierarchical set of automatic maintenance database configuration parameters AUTO_MAINT (parent of all other parameters) AUTO_DB_BACKUP AUTO_TBL_MAINT (parent of all table maintenance parameters) AUTO_RUNSTATS AUTO_STATSPROF Turn on all three values in blue to enable automatic AUTO_PROFUPD runstats AUTO_REORG
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Automated Statistics Collection Instead of the DBA triggering the statistic collection (deciding when to run RUNSTATS and which statistics to collect), there will be a background process which determines statistics that are out of date and collects them Checking if RUNSTATS is needed takes place every two hours There is no way for the DBA to change this at this time Monitoring: Messages in the db2diag.log file indicate start / termination (success/failure) of automatic runstats execution
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Automatic Statistics Collection – db2diag.log For databases with automatic runstats enabled you will see messages like the following in the db2diag.log: 2006-08-01-17.06.20.137341+120 I26461795A322 LEVEL: Event PID : 23400 TID : 2369 PROC : db2hmon 0 INSTANCE: db2air NODE : 000 FUNCTION: DB2 UDB, Automatic Table Maintenance, db2HmonEvalStats, probe:100 START : Automatic Runstats: evaluation has started on database AIR 2006-08-01-17.18.31.757646+120 I26592803A377 LEVEL: Event PID : 23400 TID : 2682 PROC : db2hmon 0 INSTANCE: db2air NODE : 000 APPID : *LOCAL.db2air.060801151840 FUNCTION: DB2 UDB, Automatic Table Maintenance, AtmTable::runstats, probe:500 START : Automatic Runstats: runstats has started on table "SAPR3 "."DFKK_TRIGGER_PAY" 2006-08-01-17.18.33.704169+120 I26593181A388 LEVEL: Event PID : 23400 TID : 2682 PROC : db2hmon 0 INSTANCE: db2air NODE : 000 APPID : *LOCAL.db2air.060801151840 FUNCTION: DB2 UDB, Automatic Table Maintenance, AtmTable::runstats, probe:900 STOP : Automatic Runstats: runstats completed successfully on table "SAPR3 "."DFKK_TRIGGER_PAY" 15 February, 2012
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Checking Database Statistics To check if database statistics are up to date you can query the STATS_TIME from the SYSCAT.TABLES system catalog view Example: db2 "select substr(tabname,1,20), stats_time from syscat.tables where tabname = ‘MYTAB‘" To check entries in db2diag.log the db2diag tool can be used. Example: db2diag –gi "function:=runstats,stop:=mytab"
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DB2 Parameters
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DB2 Environment Configure the DB2 environment via: DB2 Profile Registry Operating System Environment Variables DB2 Database Manager Configuration Parameters DB2 Database Configuration Parameters Server machine OS environment variables
Instance
Database manager configuration file
DBM CFG
Database DB2 registry New features, platform dependent parameters, special optimizations
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Database configuration file
DB CFG
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DB2 Profile Registry Variables Use the db2set command to update registry variables Parameters can be set globally or for a specific instance: To set a parameter for current instance: db2set parameter=value To set a parameter for a specific instance: db2set parameter=value -i instance_name To set a parameter at the global level: db2set parameter=value -g Changes take effect after the instance has been restarted.
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Registry Variables for SAP Installations For SAP installations a special aggregate registry variable has been designed: db2set DB2_WORKLOAD=SAP To see the values that are included in DB2_WORKLOAD=SAP run db2set –gd DB2_WORKLOAD=SAP
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Aggregate Registry Variables – Example V8.2 [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i] [i]
DB2_WORKLOAD=SAP DB2_MDC_ROLLOUT=YES [DB2_WORKLOAD] DB2_SKIPINSERTED=YES [DB2_WORKLOAD] DB2_VIEW_REOPT_VALUES=YES [DB2_WORKLOAD] DB2_OBJECT_TABLE_ENTRIES=65532 [DB2_WORKLOAD] DB2_OPTPROFILE=YES [DB2_WORKLOAD] These values have DB2_IMPLICIT_UNICODE=YES [DB2_WORKLOAD] been overwritten DB2_INLIST_TO_NLJN=YES [DB2_WORKLOAD] (signified by the [O]) DB2_MINIMIZE_LISTPREFETCH=YES [DB2_WORKLOAD] DB2_UPDATE_PART_KEY=YES [DB2_WORKLOAD] DB2_REDUCED_OPTIMIZATION=4,UNIQUEINDEX,JOIN [0] DB2NOTIFYVERBOSE=YES [DB2_WORKLOAD] DB2_INTERESTING_KEYS=YES [DB2_WORKLOAD] DB2_EVALUNCOMMITTED=YES_DEFERISCANFETCH [DB2_WORKLOAD] DB2_ANTIJOIN=EXTEND [DB2_WORKLOAD] DB2_SKIPDELETED=NO [0] DB2MEMMAXFREE=2000000 [DB2_WORKLOAD] DB2_RR_TO_RS=YES [DB2_WORKLOAD] DB2_FORCE_FCM_BP=YES [DB2_WORKLOAD]
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DB2 Configuration Parameters Two groups of parameters: Database Manager Configuration parameters (DBM CFG) Database Configuration parameters (DB CFG) Types of parameters: Configurable (changes take effect after restart) Configurable Online (no restart required) Configurable Automatic (self tuning) Informational
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How To Change The Parameters? Parameters can be viewed/modified using the following CLP commands: Database Manager Configuration commands: GET DATABASE MANAGER CONFIGURATION (or: GET DBM CFG) UPDATE DATABASE MANAGER CONFIGURATION (or: UPDATE DBM CFG) Database Configuration commands: GET DATABASE CONFIGURATION FOR (or: GET DB CFG FOR ) UPDATE DATABASE CONFIGURATION FOR (or: UPDATE DB CFG FOR ) 15 February, 2012
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Database Manager Configuration – Sample Output Database Manager Configuration Node type = Enterprise Server Edition with local and remote clients ... Diagnostic error capture level (DIAGLEVEL) = 3 Notify Level (NOTIFYLEVEL) = 3 Diagnostic data directory path (DIAGPATH) = ... Default database monitor switches Buffer pool (DFT_MON_BUFPOOL) = ON Lock (DFT_MON_LOCK) = ON Sort (DFT_MON_SORT) = ON ... Database monitor heap size (4KB) (MON_HEAP_SZ) = 66 Java Virtual Machine heap size (4KB) (JAVA_HEAP_SZ) = 512 Audit buffer size (4KB) (AUDIT_BUF_SZ) = 0 Size of instance shared memory (4KB) (INSTANCE_MEMORY) = AUTOMATIC ... Maximum query degree of parallelism (MAX_QUERYDEGREE) = ANY Enable intra-partition parallelism (INTRA_PARALLEL) = YES ... No. of int. communication buffers(4KB)(FCM_NUM_BUFFERS) = AUTOMATIC No. of int. communication channels (FCM_NUM_CHANNELS) = AUTOMATIC ...
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Some Important DBM CFG Parameters
DIAGLEVEL DIAGPATH Monitor Switches NUM_POOLAGENTS SVCENAME INTRA_PARALLEL
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(Diagnostic Error Capture Level) (Diagnostic Data Directory Path) (DFT_MON_SORT, …) (Size of the DB2 agent pool) (TCP/IP Service Name) (Enables Intra-Partition Parallelism)
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Database Configuration – Sample Output Database Configuration for Database sample Database configuration release level Database release level ... Self tuning memory (SELF_TUNING_MEM) Size of database shared memory (4KB) (DATABASE_MEMORY) Max storage for lock list (4KB) (LOCKLIST) Percent. of lock lists per application (MAXLOCKS) Package cache size (4KB) (PCKCACHESZ) Sort heap thres for shared sorts (4KB) (SHEAPTHRES_SHR) Sort list heap (4KB) (SORTHEAP) ... Changed pages threshold (CHNGPGS_THRESH) Number of asynchronous page cleaners (NUM_IOCLEANERS) Number of I/O servers (NUM_IOSERVERS) Index sort flag (INDEXSORT) Sequential detect flag (SEQDETECT) Default prefetch size (pages) (DFT_PREFETCH_SZ) ...
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= 0x0b00 = 0x0b00 = = = = = = =
ON AUTOMATIC 50 22 (MAXAPPLS*8) 5000 256
= = = = = =
60 AUTOMATIC AUTOMATIC YES YES AUTOMATIC
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Some Important DB CFG Parameters
BUFFPAGE LOCKLIST SORTHEAP UTIL_HEAP_SZ NUM_IOCLEANERS NUM_IOSERVER LOGFILSIZ LOGPRIMARY LOGSECOND
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(Buffer Pool Size) (Size limit for Lock List) (Size limit for one active sort operation) (Utilities Heap Size) (Number of Page Cleaners) (Number of I/O Servers - Prefetchers) (Log File Size) (Number of Primary Log Files) (Number of Secondary Log Files)
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Configuration Commands Enhancements GET DBM CFG SHOW DETAIL Displays detailed information showing the current value of database manager configuration parameters as well as the value of the parameters the next time you start the instance GET DB CFG FOR SHOW DETAIL Displays detailed information showing the current value of database configuration parameters as well as the value of the parameters the next time you activate the database
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GET DB CFG SHOW DETAIL – Example Output Database Configuration for Database Description Parameter Current Value Delayed Value ----------------------------------------------------------------------------------------------------------Database configuration release level Database release level Database territory Database code page Database code set Database country/region code Database collating sequence Alternate collating sequence Database page size Dynamic SQL Query management Discovery support for this database
= 0x0a00 = 0x0a00 = = = = = (ALT_COLLATE) = =
en_US 1208 UTF-8 1 IDENTITY_16BIT
IDENTITY_16BIT
4096
4096
(DYN_QUERY_MGMT) = DISABLE (DISCOVER_DB) = ENABLE
Default query optimization class (DFT_QUERYOPT) Degree of parallelism (DFT_DEGREE) Continue upon arithmetic exceptions (DFT_SQLMATHWARN) Default refresh age (DFT_REFRESH_AGE) Default maintained table types for opt (DFT_MTTB_TYPES) Number of frequent values retained (NUM_FREQVALUES) Number of quantiles retained (NUM_QUANTILES)
= = = = = = =
5 1 NO 0 SYSTEM 10 20
Backup pending
= NO
DISABLE ENABLE 5 1 NO 0 SYSTEM 10 20
[…]
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DB2 Configuration Parameters & SAP As a starting point to tune your SAP DB2 database follow the SAP recommendations. SAP notes with DB2 standard parameter settings: 584952 – DB2 UDB ESE V8.1 and V8.2 899322 – DB2 9.1 Standard Parameter Settings 1086130 – DB2 9.5 Standard Parameter Settings 1329179 – DB2 9.7 Standard Parameter Settings
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Problem Determination
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Problem Source Identification Essential diagnostic information to identify the source of a problem: db2diag.log db2level DB2 configuration (instance, database, registry) Other possible information needed SAP/IBM support: db2nodes.cfg, trap/ dump files, stack files, core files, db2dart, DB2 Trace … Environment (set or env) Use the db2support tool to collect the data
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First-failure Data Capture (FFDC) First-failure data capture (FFDC) information is the set of diagnostic information that DB2 captures automatically when errors occur. Configuration parameters: The DIAGPATH dbm parameter specifies the path to the FFDC storage directory The DIAGLEVEL and NOTIFYLEVEL parameters control the detail of information you receive in the log files. The information captured by FFDC includes the following: db2diag.log and administration notification log Dump files and trap files Core files (on UNIX)
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DB2DIAG.LOG The first and most important source for problem analysis! Contains records about errors, warnings and informational records. Typical locations of DB2DIAG.LOG (values of DIAGPATH) Standard on UNIX: $HOME/sqllib/db2dump Standard SAP Installation on UNIX: /db2//db2dump Standard on Windows: \\
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DB2DIAG.LOG – DIAGLEVEL DIAGLEVEL 0 No logging 1 Severe errors 2 Severe and non-severe errors 3 Severe and non-severe errors plus warnings 4 Severe and non-severe errors, warnings and Info Default is 3 and acceptable for most of the time Level 4 generates a lot of information - only useful in special situations (e.g. installation, migration)
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DB2DIAG.LOG – Examples (1/3) Timestamp & time zone 2004-07-14-15.45.13.569918+120 I1A895 LEVEL: Event PID : 20940 TID : 1 PROC : db2agent (instance) 0 INSTANCE: db2xdm NODE : 000 DB : XDM APPHDL : 0-474 APPID: *LOCAL.db2xdm.040714163353 FUNCTION: DB2 UDB, RAS/PD component, _pdlogInt, probe:120 Severity level START : New db2diag.log file DATA #1 : Build Level, 144 bytes Instance "db2xdm" uses "64" bits and DB2 code release "SQL08020" with level identifier "03010106". Informational tokens are "DB2 v8.1.0.64", "s040704", "U498351", FixPak "7". DATA #2 : System Info, 1328 bytes System: SunOS us0014 5.8 Generic_108528-11 sun4u DB2 level information CPU: total:4 online:4 for started instance Physical Memory: total:2048 free:644 Virtual Memory: total:10229 free:7466 Swap Memory: total:8181 free:6822 Information in this record is only valid at the time when this file was created (see this record's time stamp).
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DB2DIAG.LOG – Examples (2/3) 2004-07-14-16.16.46.431884+120 I53029A379 LEVEL: Event PID : 23827 TID : 1 PROC : db2agent (instance) 0 INSTANCE: db2xdm NODE : 000 APPHDL : 0-8 APPID: *LOCAL.db2xdm.040714141645 FUNCTION: DB2 UDB, config/install, sqlfLogUpdateCfgParam, probe:20 CHANGE : CFG DB XDM: "Util_heap_sz" From: "5000" To: "131072"
Changes to configuration files documented in db2diag.log 2004-07-14-19.02.54.893205+120 E123020A589 LEVEL: Error PID : 7207 TID : 1 PROC : db2agent (XDM) 0 INSTANCE: db2xdm NODE : 000 DB : XDM APPHDL : 0-9 APPID: *LOCAL.db2xdm.040714165506 FUNCTION: DB2 UDB, buffer pool services, sqlbAllocateExtent, probe:830 MESSAGE : ADM6044E The DMS table space "PSAPLOADI" (ID "20") is full. Additional space can be added to the table space by either adding new containers or extending existing ones using the ALTER TABLESPACE SQL statement.
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DB2DIAG.LOG – Examples (3/3) OS error Called OS function
Unique record ID
2006-04-21-15.26.11.839221+120 E6835E555 LEVEL: Error (OS) PID : 6259 TID : 182968115104PROC : db2med.6158.0 0 INSTANCE: db2a3m NODE : 000 FUNCTION: DB2 UDB, oper system services, sqloLoadModule, probe:190 CALLED : OS, -, dlopen OSERR: EINTR (4) DATA #1 : Library name or path, 21 bytes /usr/lib/libnsrdb2.so DATA #2 : shared library load flags, PD_TYPE_LOAD_FLAGS, 4 bytes Formatted 0 error code DATA #3 : String, 80 bytes /usr/lib/libnsrdb2.so: cannot open shared object file: No such file or directory
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OS
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Administration Notification Log In addition to the db2diag.log an administration notification log (aka notify log) is available: Focus on administrative events (db2diag.log is intended for problem determination). Intended for use by database and system administrators. Notification messages also provide additional information to supplement the SQLCODE. The notification log is available on UNIX & Linux. On Windows it is part of the Windows Event Log The type of event and the level of detail of the information gathered are determined by the NOTIFYLEVEL (DBM parameter) Location defined by DIAGPATH configuration parameter File name is .nfy (for example db2sxi.nfy) Log messages are NLS enabled (i.e. printed in the locale of the database) while the db2diag.log is always in English
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DB2 Notify Log – Examples With Errors 2005-03-24-11.34.29.242569 Instance:db2sxi Node:000 PID:89198(db2agent (SXI )) Appid:*LOCAL.db2inst1.020205091435 recovery manager sqlpresr Probe:370 Database:SXI ADM1531E Crash recovery has completed successfully. 2005-06-08-11.46.52.310415 Instance:db2sxi Node:000 PID:23941(db2wdog 0 0) TID:332701696 Appid:none oper system services sqloRunInstance Probe:490 ADM0503C An unexpected internal processing error has occurred. ALL DB2 PROCESSES ASSOCIATED WITH THIS INSTANCE HAVE BEEN SHUTDOWN. Diagnostic information has been recorded. Contact IBM Support for further assistance.
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Diagnostic Information for IBM customer support In addition to the db2diag.log (and the administration notification) you may find the following files in the DIAGPATH, for example: Trap files: Function call stack, signals, exceptions. Core files: Memory image of terminated processes. Dump files: Additional information (control blocks etc) DB2 event log: Circular log of infrastructure-level events occurring in the database manager. …
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A Typical DB2 DIAGPATH -rw-r--r--rw-rw-rw-rw-r-----rw-r----drwxr-xr-x -rw-r--r--rw-r--r--rw-r--r--rw-r--r--rw-r--r--rw-r--r--rw-r--r--rw-r--r-drwxr-x---rw-r--r-drw-rw-rw-rw-r--r--rw-rw-rw-
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1 1 1 1 2 1 1 1 1 1 1 1 1 2 1 1 1 1
db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt db2qpt root root db2qpt db2qpt db2qpt
sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm sysadm
747988 May 6 4124675 Jun 16 6291376 Jul 18 6291376 Feb 12 4096 Feb 12 2731 Feb 12 2731 Feb 12 2731 Feb 12 2731 Feb 12 2729 Feb 12 2730 Feb 12 2730 Feb 12 2730 Feb 12 4096 Mar 1 14699 Mar 1 19514552 May 2 9262825 May 2 305440156 May
Event log
2005 xbsa.log 2005 db2diag.log_2005-06-16-10.59.37 2005 db2eventlog.000.crash db2dart files 15:57 db2eventlog.000 16:58 DART0000 17:04 t22378.000 17:19 t24338.000 17:34 t26239.000 Trap files 17:49 t28312.000 18:04 t228.000 18:19 t2447.000 18:34 t4466.000 Core file 18:49 t6428.000 19:37 c16591.000 19:37 t16591.000 13:27 db2qpt.nfy 15:29 UserExit.log 2 15:29 db2diag.log
Notify log
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Collect System Diagnostic Information – db2support The db2support utility is designed to automatically collect all DB2 and system diagnostic information available The utility will collect for example: The db2diag.log, all trap files, lock list files, dump files, buffer pool and table space control files, database and database manager configuration, system information … Collecting most of the information required to debug a problem: db2support -d -c Information is stored in a compressed ZIP archive db2support.zip
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DB2 Monitoring and Performance Tuning
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DB2 Monitoring and Performance Tuning Memory management Self Tuning Memory Manager (STMM) Monitoring Tools (e.g. snapshots, db2pd) DB2 Parallelism (intra- and inter partition parallelism)
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DB2 Memory Database Shared Memory Visible to all processes Some restrictions apply for older DB2 releases (e.g. number of shared memory segments is limited on 32 bit plattforms) Private Memory Visible only to the process that allocates it
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DB2 Memory Areas Database Manager Shared Memory
Database Global Memory Database DatabaseGlobal GlobalMemory Memory
Application Global Memory Application ApplicationGlobal GlobalMemory Memory
Agent Private Memory Agent AgentPrivate PrivateMemory Memory Agent/ Application Shared Memory Agent/ Agent/Application ApplicationShared SharedMemory Memory 15 February, 2012
•Allocated when database manager is started. •Contains monitor heap, FCM buffers, etc. •Allocated when database is activated. •Contains buffer pools, locklist, shared sort area, package cache, etc.
•Allocated when an application connects to the database •Used e.g. for communication between agents that work on the same SQL statement (if intra_parallel is enabled). •Allocated when an agent is created •Used e.g. for private sort heap •Allocated e.g. when a client issues a connect request •Used for communication between an agent and an application 125
Consumers of Database Global Memory Database Global Memory contains the following areas which can be adjusted online: Buffer pools (most important tuning area) Sort heap Lock list Package cache, catalog cache Utility Heap Database heap (e.g. log buffers) Size of Database Global Memory is defined by parameter database_memory. If database_memory is set to computed DB2 computes an appropriate value when the database is activated.
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Memory Tuning in DB2 9 – STMM DB2 9 introduces the Self Tuning Memory Manager (STMM): STMM senses the underlying workload and adjusts the size of the most important memory areas accordingly Can adapt quickly to workload shifts that require memory redistribution Adapts tuning frequency based on workload Database memory areas that can be dynamically adjusted by STMM: Buffer pools Sort heap Lock list Package cache Total size of database memory
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STMM – Activating Self Tuning Memory 1. Update your database configuration for all consumers: db2 update db cfg for using LOCKLIST AUTOMATIC MAXLOCKS AUTOMATIC PCKCACHESZ AUTOMATIC SORTHEAP AUTOMATIC SHEAPTHRES_SHR AUTOMATIC 2. Enable your bufferpools for STMM tuning: db2 alter bufferpool size AUTOMATIC 3. Set DATABASE_MEMORY to automatic: db2 update db cfg for using DATABASE_MEMORY AUTOMATIC 4. Switch on STMM: db2 update db cfg for using SELF_TUNING_MEM ON
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Buffer Pool - Overview A buffer pool is a storage area into which database pages (containing table rows or index entries) are temporarily read (and optionally changed). The purpose of the buffer pool is to improve database system performance (data can be accessed faster from memory than from disk). Multiple buffer pools can be configured for a database, e.g. to ensure that frequently accessed small tables are not swapped out by large tables. Buffer pools are assigned to table spaces, i.e. different table spaces may use different buffer pools.
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Buffer Pool Allocation Guidelines Buffer pool size specification Too small buffer pools may result in excessive disk I/O. Oversized buffer pools may result in paging. How to specify the buffer pool size: ALTER BUFFERPOOL name SIZE Let STMM figure out the optimal size of bufferpools depending on current workload. Guidelines The buffer pool should use at least 1/2 of the available memory A well tuned system should have a buffer pool hit ratio larger 96 percent
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Sort Memory Database Partition 1 Database Partition 0
Sort Heap
Sort
Sort
Sort
Sort memory for one active sort (SORTHEAP defines allowed maximum)
Total sort memory (SHEAPTHRES / SHEAPTHRES_SHR define limit per partition)
Allocation of sort memory:
INTRA_PARALLEL=OFF ⇒ Sort memory is „agent private memory“. ⇒ SHEAPTHRES is a soft limit for total sort memory of each database partition.
INTRA_PARALLEL=ON ⇒ Sort memory is shared memory. ⇒ Sort memory of size SHEAPTHRES_SHR is a hard limit for total sort memory. ⇒ SHEAPTHRES_SHR can be defined per partition.
Recommendations for initial sizing (SORTHEAP,SHEAPTHRES) are described in SAP notes 584952 (DB2 V8) and 899322 (DB2 9): SHEAPTHRES = #wp * sortheap 15 February, 2012
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Sort Overflow Sort Heap
Sort
Bufferpool
Sort
Tempory TS
Sort
Real Memory
Disk
Sort
Sort
A sort overflow occurs, if a sort requires more memory than defined by SORTHEAP: The sort operation first continues in the Bufferpool. If the Bufferpool is too small, the sort operation uses a temporary tablespace This means sorting on disk!
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DB2 Monitoring Tools
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The DB2 Memory Tracker The DB2 memory tracker tool db2mtrk offers a complete report of memory status for instances, databases, and agents. This command outputs the following memory pool allocation information: Memory type (e.g. bph = buffer pool) Current size Maximum size Largest size (high water mark) Agent who allocated memory pool (for private memory)
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The DB2 Memory Tracker Command Syntax:
i: instance memory d: database memory p: private memory
>>-db2mtrk--+---+--+---+--+---+--+---+------------------------> '-i-'
'-d-'
'-p-'
+-m-+
m: maximum value w: high water mark
'-w-'
>--+------------------------+--+---+--+---+----------------->< '-r--interval--+-------+-'
'-v-'
'-h-'
'-count-' v: verbose output h: help screen
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Example Output db2mtrk usdbair:db2air 2% db2mtrk -i -d Tracking Memory on: 2006/08/01 at 15:39:54 Memory for instance monh 240.0K
other 3.1M
Buffer pool IBMDEFAULTBP
Memory for database: AIR utilh 448.0K
pckcacheh catcacheh bph(1) bph(S32K) bph(S16K) bph(S8K) 147.5M 47.0M 23.1G 672.0K 416.0K 288.0K
bph(S4K) 224.0K
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lockh 210.6M
dbh 38.8M
other 0
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Monitoring System Performance Information about the system perform can be gathered using the following facilities: Snapshot monitor: A snapshot monitor provides cumulative information in the form of counters (e.g. number of logical and physical reads), and state information (e.g. currently held locks). They are used in the performance tuning of instances, databases, and applications running on DB2. Event monitor: An event monitor records the database activity when an event or transition occurs. They are used for example to record deadlocks, or executed SQL statements.
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Using DB2 Snapshots (1/2) The DB2 GET SNAPSHOT command can be used to monitor different areas of DB2 performance Database Manager Snapshot: db2 get snapshot for database manager Database Snapshot: db2 get snapshot for database on Table Snapshot: db2 get snapshot for tables on Bufferpool Snapshot: db2 get snapshot for bufferpools on Lock Snapshot: db2 get snapshot for locks on
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Using DB2 Snapshots (2/2) Application Snapshot: db2 get snapshot for application {APPLID appl-id | AGENTID applhandle} All information: db2 get snapshot for all on If using ESE with DPF you may limit snapshot to a certain partition or execute on all partitions: Single partition: db2 get snapshot for bufferpools on at dbpartitionnum All partitions: db2 get snapshot for database on global
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Example Output – GET SNAPSHOT FOR DB Database Snapshot Database name = CC4 Database path = /db2/CC4/db2cc4/NODE0000/SQL00001/ Input database alias = CC4 Database status = Active Catalog database partition number = 0 Catalog network node name = Operating system running at database server= LINUX Location of the database = Local First database connect timestamp = 11-06-2003 12:51:36.021102 Last reset timestamp = Last backup timestamp = 11-18-2003 02:27:44.195653 Snapshot timestamp = 11-18-2003 14:24:33.810170 High water mark for connections = Application connects = Secondary connects total = Applications connected currently = Appls. executing in db manager currently = Agents associated with applications = Maximum agents associated with applications= Maximum coordinating agents = Locks held currently Lock waits [...] 15 February, 2012
24 2110 0 21 0 21 24 24
= 0 = 27183 140
Snapshot – SQL Table Functions Snapshot information can be retrieved with SQL Table Functions, for example: SNAPSHOT_BP(, ) Returns buffer pool information SNAPSHOT_DATABASE(, ) Returns information from a database snapshot SNAPSHOT_TBS(, ) Returns information from a table space snapshot Example: Get number of buffer pool logical and physical reads: SELECT POOL_DAT_L_READS, POOL_DATA_P_READS FROM TABLE(SNAPSHOT_BP(‘', 0)) AS S 15 February, 2012
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Snapshot – SQL Administrative Views (V9) Snapshot information can be also retrieved with SQL Administrative Views. More convenient usage (e.g. syntax) than SQL table functions. Examples: SYSIBMADM.SNAPDB -> Database snapshot SYSIBMADM.SNAPTBSP -> Table space snaphot SYSIBMADM.SNAPTAB -> Table snapshot Usage example: DESCRIBE TABLE SYSIBMADM.SNAPDB SELECT SORT_OVERFLOWS FROM SYSIBMADM.SNAPDB
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DB2 Event Monitors – SAP In a SAP environment DB2 event monitors are used for monitoring deadlock situations Two event monitors are created as part of the SAP Installation db2 "create event monitor DB6_EDLMON1 for DEADLOCKS write to FILE '/db2//db2event/edlmon1' MAXFILES NONE BUFFERSIZE 2 BLOCKED REPLACE AUTOSTART" db2 "create event monitor DB6_EDLMON2 for DEADLOCKS write to FILE '/db2//db2event/edlmon2' MAXFILES NONE BUFFERSIZE 2 BLOCKED REPLACE“ Entries can be seen in transaction ST04 or by using db2evmon
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Monitor And Troubleshoot Command db2pd The utility db2pd retrieves information from DB2 memory sets (Created to look, feel, and function like Informix onstat utility) Runs very quickly as it is not acquiring any locks or latches Runs outside of the engines resources (even works on a hanging engine) The tool can provide a wide range of information, for example: Buffer Pools Table spaces (and table space containers) Dynamic SQL statements Agents, applications, locks, transactions Logs
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The db2pd Command – Examples To see all memory sets of the instance, and repeat this five times with an interval of 30 seconds, enter: db2pd –memsets –repeat 30 5 To see all memory sets of a database, enter: db2pd –memsets –db mydb To see the database configuration for database XDM (current and delayed values), enter: db2pd –db XDM –dbcfg To see all bufferpools of all databases of the instance, enter: db2pd –alldbs –bufferpools To get the dynamic SQL cache and put it into a file, enter: db2pd –db sample –dynamic file=dynamic.txt
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Screen Shot – db2pd For Buffer Pools Address Id Name NumTbsp PgsToRemov CurrentSz PostAlter 0x0000000221B98540 1 IBMDEFAULTBP 0 138056 138056 0 0x000000022073F280 4096 IBMSYSTEMBP4K 0 16 16 0 0x000000022073F6C0 4097 IBMSYSTEMBP8K 0 16 16 0 0x000000022073FB00 4098 IBMSYSTEMBP16K 0 16 16 0 0x0000000221B98100 4099 IBMSYSTEMBP32K 0 16 16 0
PageSz PA-NumPgs SuspndTSCt 16384 138056
BA-NumPgs
BlkSize
0
0
7
4096
16
0
0
0
8192
16
0
0
0
16384
16
0
0
0
32768
16
0
Buffer0pool hit ratio0 new with DB2 9
Bufferpool Statistics for all bufferpools (when BUFFERPOOL monitor switch is ON): BPID DatLRds DatPRds HitRatio TmpDatLRds TmpDatPRds HitRatio IdxLRds HitRatio TmpIdxLRds TmpIdxPRds HitRatio 1 1880491027 6819397 99.64% 1043024 311 99.97% 363097957 99.42% 0 0 00.00% 4096 0 0 00.00% 0 0 00.00% 0 00.00% 0 0 00.00% […]
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IdxPRds 2113817 0
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DB2 Monitoring in SAP Environment In a SAP environment transaction DB6Cockpit can be used to administer, monitor, and tune DB2. Use transaction ST04 to monitor the performance of your DB2 database, for example: Buffer pool hit ratio Hit ratio of Catalog Cache and Package Cache I/O Performance Lock situations Query the SQL cache Table space
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DB2 Database Parallelism
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Deployment of DB2 Parallelism for SAP Systems INTRA_PARALLEL=OFF:
Recommended for all SAP NW04s usage types, but not for SAP BI single-partition systems. ⇒ Each SQL-Statement is processed by a single database agent. INTRA_PARALLEL=ON:
Recommended for small SAP BI systems with a single database partition and at least 2 CPUs. ⇒ SAP BI specific queries are processed by multiple database agents. ⇒ Parallel index build. ⇒ Limited scalability but ease of administration compared to DPF. ⇒ Shared memory is allocated for sorts (parameter SHEAPTHRES_SHR). Multiple Database Partitions and INTRA_PARALLEL=OFF:
Recommended for large SAP BI systems with many CPUs. ⇒ Almost linear scalability for SAP BI queries. ⇒ Administration overhead because of multiple partitions. 15 February, 2012
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SAP and DB2
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SAP And DB2 Supported Combinations All supported SAP kernel versions are running with DB2 Version 8.2 and DB2 Version 9. The IBM/SAP Integration Center in Toronto tests compatibility with SAP software for all new DB2 versions or Fix Packs. The SAP Service Market Place provides information about supported combinations of SAP software and DB2 versions: http://service.sap.com/platforms Every Fix Pack that was successfully tested is documented in SAP Note 101809 "DB6: Supported Fix Packs for DB2 UDB for UNIX/Windows" Do not download a Fix Pack from the IBM Support web page for use with SAP software! 15 February, 2012
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SAP/DB2 Software Layers SAP Web Application Server Dispatcher disp+work[.exe]
User Environment: SAPSYSTEMNAME= DIR_LIBRARY= dbs_db6_schema=sap dbms_type=db6 DB2INSTANCE=db2 DB2DBDFT=
External SAP executables (part of SAP Kernel) With DBSL access, for example R3load, tp, R3trans, R3ldctl SAP DBSL dbdb6slib.[o,so,sl,dll] DB2 CLI libdb2 / db2cli.dll
SAP Work Processes SAP DBSL dbdb6slib.[o,so,sl,dll] DB2 CLI libdb2 / db2cli.dll
Without DBSL access, for example dmdb6srp ... DB2 CLI libdb2 / db2cli.dll
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DB2 Instances and R/3 Instances A SAP system, identified by the , consists of: One or more R/3 instances (dialog / central instance) The DB2 database instance DB2, which contains: Database which is used by the SAP system Database ADM is optional and may be used for log file management with older DB2 releases. You may run multiple SAP systems within a single DB2 database (MCOD System). For MCOD systems each SAP component uses a dedicated database schema (SAPSID) for the corresponding database objects.
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UNIX Users for DB2 and SAP db2 adm sapr3
DB2 instance owner SAP system administrator Owner of database objects, connect user MCOD Systems: sapr3 is replaced by sap user sapdb Schema for Java Engine db2as DB2 Administration Server owner
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DB2 Directory Structure in SAP Environment Directory structure under UNIX: /db2/db2 /db2/db2/sqllib /db2/db2/db2_v9 /db2//db2 /db2//sapdata[n] /db2//saptemp1 /db2//log_dir
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$HOME of db2 DB2 instance DB2 9 software Database directory DB2 directories for table space containers File system for SMS temporary table spaces DB2 online log directory
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Table Spaces in SAP Environment In a standard SAP installation, all user table spaces are created as DMS table spaces Containers are located in the /db2//sapdata file systems The temporary table spaces PSAPTEMP & PSAPTEMP16 are created as SMS table spaces Containers are located in the /db2//saptemp1 file system All newer SAP systems are using automatic storage per default New SAP releases use uniform page size 16k, uniform extent size 2, and automatic prefetch size.
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SAP DB2 Tablespaces (NW04s ABAP+Java) Uniform page size of 16K with SAP Basis 6.40 Uniform extent size of 2 with SAP Basis 7.00
Database Server Database Partition 0 SAP Basis Tablespaces ABAP ABAP Schema SAP
SAP BI Tablespaces ABAP
Java Schema SAPDB
SAP Basis Tablespaces Java
Tablespaces (D/I) SYSCATSPACE SAPSID#TEMP SAPSID#USER1 SAPSID#EL SAPSID#ES SAPSID#LOAD SAPSID#SOURCE SAPSID#DDIC SAPSID#PROT SAPSID#CLU SAPSID#POOL SAPSID#STAB SAPSID#BTAB
Usage DB2 data dictionary Sort, temp tables, reorg Default TS Dev. Environment Loads Dev. Environment Sources Screen and Report Loads Screen and Report Sources ABAP Dictionray Log-like tables (e.g. Spool) Cluster tables Pool tables (e.g. ATAB) Master data Transaction data
SAPSID#ODS SAPSID#DIM SAPSID#FACT
ODS, PSA tables Dimension tables InfoCube and Aggregate fact tables Tablespaces for Java Stack
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DB2 Security in SAP Environment
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DB2 Database Authorities in SAP Environment
SYSADM (UNIX user db2, UNIX group dbadm) Highest level of administrative authority. Users in this group can run all utilities and control all database objects in the instance. User db2 is used to create, backup, and restore the SAP database. SYSCTRL (UNIX user adm, UNIX group dbctl) Users in this group can perform maintenance and utility operations against the DB2 instance. But they are not allowed direct access to data in the databases. User adm may be used to start or stop the db2 instance/database SYSMAINT (UNIX user sap, UNIX group dbmnt) Perform maintenance operations on all databases associated with an instance without having direct access to data. User sap is e.g. used to create SAP tables, to connect to the database, and to take DB2 snapshots.
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SAP DB2 Connect User Password Encryption disp+work process retrieves and decrypts password of SAP connect user (sap) from password file dscdb6.conf: UNIX:
/usr/sap//SYS/global/dscdb6.conf
Windows:
\\%DSCDB6HOME%\sapmnt\\SYS\global\dscdb6.conf
Environment variable 'DB2DB6EKEY' is used by SAP for password encryption/decryption (the value of DB2DB6EKEY has to be identical on all SAP servers that belong to the SAP system). SAP connect user is defined by environment variable dbs_db6_schema und SAP profile parameter dbs/db6/schema
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Maintenance of SAP DB2 User Passwords Maintenance of passwords with program dscdb6up Create password file dscdb6.conf with password of connect user (sapr3/sap) or the SAP administrator (sid): dscdb6up -create Change password of corresponding user: dscdb6up Please remember: After changing the OS password for either the connect user or the SAP administrator you must also update the dscdb6.conf file!
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Overview - SAP DB2 Password Encryption User: adm
SAP work process (disp+work[.exe])
db2 connect to user sap using
Database Server
Read (decrypt)
dscdb6.conf
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Create/ update (encrypt)
dscdb6up[.exe]
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DB2 Authentication in SAP Environment
In an SAP environment, DB2 runs with authentication SERVER_ENCRYPT. When the SAP application connects to the DB2 database the following tasks are performed by DB2: 1. The SAP connect user password is encrypted by the DB2 client before it is send over the network. 2. The connect user and encrypted password are send to the DB2 database server. 3. The DB2 database server uses operating system services to authenticate the user.
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SAP DB2 Administration Tools The SAP DB2 Admin Tools are a collection of tools specific to the SAP environment, which supplement standard DB2 tools They can be divided into the following categories: Log file management tools Database backup and restore support tools Performance related tools Please note: Most of the tools have become obsolete with newer SAP releases and DB2 9
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Overview Of DB2 SAP Administration Tools
sddb6ins brarchive brrestore db2uext2 db6adutl dmdb6rdi dmdb6srp dmdb6rts brdb6brt db6util dmdb6bkp
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Admin Tools Installation Log file management Log File Archive Tool tools are supported for Log File Retrieval Tool SAP Rel.
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