Hello DBAs,

I have a question regarding DB2 performance. I have installed DB2 on SUSE 10 SP1 64bit and tried to restore a small database. What I noticed at the operating system is that the IO Queue depth is always at 1 and never get more than 1. My Qlogic HBA setting is at 128. When I run IOZone test, I get 128 IO Queue depth. Is the DB2 restore operation single-threaded? Or is there a way to tune DB2 to get more IO Queue depth? Please help me as this is too slow. Doesn't matter what I do (restore, create tablespace, etc..) I get only 1 outstanding IO when I run iostat -x. Any other test tools did not do this on my server so I suspect it's DB2.

thanks,

dbuser001

What DB2 version?
What is the configuration parameters
of the instance?
of the database?
db2set?

Andy

DB2 version is 9.5.
Single container
db2inst1@Dell6850b:~> db2set -i
DB2_SKIPINSERTED=ON
DB2_EVALUNCOMMITTED=YES
DB2_SKIPDELETED=ON
DB2COMM=tcpip

What are the configuration parameters of the instance and the db?
("GET DBM CFG" and "GET DB CFG FOR MyDB")

Andy

Hi Andy,

I tried to copy and paste the output but it's only working.

db2inst1@Dell6850b:~> db2 get db cfg for PRDXNGPS

Database Configuration for Database PRDXNGPS

Database configuration release level = 0x0c00
Database release level = 0x0c00

Database territory = US
Database code page = 1208
Database code set = UTF-8
Database country/region code = 1
Database collating sequence = IDENTITY
Alternate collating sequence (ALT_COLLATE) =
Number compatibility = OFF
Varchar2 compatibility = OFF
Database page size = 4096

Dynamic SQL Query management (DYN_QUERY_MGMT) = DISABLE

Discovery support for this database (DISCOVER_DB) = ENABLE

Restrict access = NO
Default query optimization class (DFT_QUERYOPT) = 5
Degree of parallelism (DFT_DEGREE) = 1
Continue upon arithmetic exceptions (DFT_SQLMATHWARN) = NO
Default refresh age (DFT_REFRESH_AGE) = 0
Default maintained table types for opt (DFT_MTTB_TYPES) = SYSTEM
Number of frequent values retained (NUM_FREQVALUES) = 10
Number of quantiles retained (NUM_QUANTILES) = 20

Decimal floating point rounding mode (DECFLT_ROUNDING) = ROUND_HALF_EVEN

Backup pending = NO

Database is consistent = YES
Rollforward pending = DATABASE
Restore pending = NO

Multi-page file allocation enabled = YES

Log retain for recovery status = RECOVERY
User exit for logging status = NO

Self tuning memory (SELF_TUNING_MEM) = ON
Size of database shared memory (4KB) (DATABASE_MEMORY) = AUTOMATIC
Database memory threshold (DB_MEM_THRESH) = 10
Max storage for lock list (4KB) (LOCKLIST) = AUTOMATIC
Percent. of lock lists per application (MAXLOCKS) = AUTOMATIC
Package cache size (4KB) (PCKCACHESZ) = AUTOMATIC
Sort heap thres for shared sorts (4KB) (SHEAPTHRES_SHR) = AUTOMATIC
Sort list heap (4KB) (SORTHEAP) = AUTOMATIC

Database heap (4KB) (DBHEAP) = AUTOMATIC
Catalog cache size (4KB) (CATALOGCACHE_SZ) = 260
Log buffer size (4KB) (LOGBUFSZ) = 256
Utilities heap size (4KB) (UTIL_HEAP_SZ) = 189807
Buffer pool size (pages) (BUFFPAGE) = 1000
SQL statement heap (4KB) (STMTHEAP) = AUTOMATIC
Default application heap (4KB) (APPLHEAPSZ) = AUTOMATIC
Application Memory Size (4KB) (APPL_MEMORY) = AUTOMATIC
Statistics heap size (4KB) (STAT_HEAP_SZ) = AUTOMATIC

Interval for checking deadlock (ms) (DLCHKTIME) = 10000
Lock timeout (sec) (LOCKTIMEOUT) = 30

Changed pages threshold (CHNGPGS_THRESH) = 10
Number of asynchronous page cleaners (NUM_IOCLEANERS) = AUTOMATIC
Number of I/O servers (NUM_IOSERVERS) = AUTOMATIC
Index sort flag (INDEXSORT) = YES
Sequential detect flag (SEQDETECT) = YES
Default prefetch size (pages) (DFT_PREFETCH_SZ) = AUTOMATIC

Track modified pages (TRACKMOD) = OFF

Default number of containers = 1
Default tablespace extentsize (pages) (DFT_EXTENT_SZ) = 32

Max number of active applications (MAXAPPLS) = AUTOMATIC
Average number of active applications (AVG_APPLS) = AUTOMATIC
Max DB files open per application (MAXFILOP) = 30720

Log file size (4KB) (LOGFILSIZ) = 4096
Number of primary log files (LOGPRIMARY) = 20
Number of secondary log files (LOGSECOND) = 235
Changed path to log files (NEWLOGPATH) =
Path to log files = /db2/data/db2inst1/NODE0000/SQL00001/SQLOGDIR/
Overflow log path (OVERFLOWLOGPATH) =
Mirror log path (MIRRORLOGPATH) =
First active log file = S0000035.LOG
Block log on disk full (BLK_LOG_DSK_FUL) = NO
Percent max primary log space by transaction (MAX_LOG) = 0
Num. of active log files for 1 active UOW(NUM_LOG_SPAN) = 0

Group commit count (MINCOMMIT) = 1
Percent log file reclaimed before soft chckpt (SOFTMAX) = 520
Log retain for recovery enabled (LOGRETAIN) = RECOVERY
User exit for logging enabled (USEREXIT) = OFF

HADR database role = STANDARD
HADR local host name (HADR_LOCAL_HOST) =
HADR local service name (HADR_LOCAL_SVC) =
HADR remote host name (HADR_REMOTE_HOST) =
HADR remote service name (HADR_REMOTE_SVC) =
HADR instance name of remote server (HADR_REMOTE_INST) =
HADR timeout value (HADR_TIMEOUT) = 120
HADR log write synchronization mode (HADR_SYNCMODE) = NEARSYNC
HADR peer window duration (seconds) (HADR_PEER_WINDOW) = 0

First log archive method (LOGARCHMETH1) = LOGRETAIN
Options for logarchmeth1 (LOGARCHOPT1) =
Second log archive method (LOGARCHMETH2) = OFF
Options for logarchmeth2 (LOGARCHOPT2) =
Failover log archive path (FAILARCHPATH) =
Number of log archive retries on error (NUMARCHRETRY) = 5
Log archive retry Delay (secs) (ARCHRETRYDELAY) = 20
Vendor options (VENDOROPT) =

Auto restart enabled (AUTORESTART) = ON
Index re-creation time and redo index build (INDEXREC) = SYSTEM (RESTART)
Log pages during index build (LOGINDEXBUILD) = OFF
Default number of loadrec sessions (DFT_LOADREC_SES) = 1
Number of database backups to retain (NUM_DB_BACKUPS) = 12
Recovery history retention (days) (REC_HIS_RETENTN) = 366
Auto deletion of recovery objects (AUTO_DEL_REC_OBJ) = OFF

TSM management class (TSM_MGMTCLASS) =
TSM node name (TSM_NODENAME) =
TSM owner (TSM_OWNER) =
TSM password (TSM_PASSWORD) =

Automatic maintenance (AUTO_MAINT) = OFF
Automatic database backup (AUTO_DB_BACKUP) = OFF
Automatic table maintenance (AUTO_TBL_MAINT) = ON
Automatic runstats (AUTO_RUNSTATS) = ON
Automatic statement statistics (AUTO_STMT_STATS) = OFF
Automatic statistics profiling (AUTO_STATS_PROF) = OFF
Automatic profile updates (AUTO_PROF_UPD) = OFF
Automatic reorganization (AUTO_REORG) = OFF

Enable XML Character operations (ENABLE_XMLCHAR) = YES
WLM Collection Interval (minutes) (WLM_COLLECT_INT) = 0

db2inst1@Dell6850b:~>

db2inst1@Dell6850b:~> db2 get dbm cfg

Database Manager Configuration

Node type = Enterprise Server Edition with local and remote clients

Database manager configuration release level = 0x0c00

CPU speed (millisec/instruction) (CPUSPEED) = 2.952151e-07
Communications bandwidth (MB/sec) (COMM_BANDWIDTH) = 1.000000e+02

Max number of concurrently active databases (NUMDB) = 8
Federated Database System Support (FEDERATED) = NO
Transaction processor monitor name (TP_MON_NAME) =

Default charge-back account (DFT_ACCOUNT_STR) =

Java Development Kit installation path (JDK_PATH) = /home/db2inst1/sqllib/java/jdk64

Diagnostic error capture level (DIAGLEVEL) = 3
Notify Level (NOTIFYLEVEL) = 3
Diagnostic data directory path (DIAGPATH) = /home/db2inst1/sqllib/db2dump

Default database monitor switches
Buffer pool (DFT_MON_BUFPOOL) = OFF
Lock (DFT_MON_LOCK) = OFF
Sort (DFT_MON_SORT) = OFF
Statement (DFT_MON_STMT) = OFF
Table (DFT_MON_TABLE) = OFF
Timestamp (DFT_MON_TIMESTAMP) = ON
Unit of work (DFT_MON_UOW) = OFF
Monitor health of instance and databases (HEALTH_MON) = ON

SYSADM group name (SYSADM_GROUP) = DB2IADM1
SYSCTRL group name (SYSCTRL_GROUP) =
SYSMAINT group name (SYSMAINT_GROUP) =
SYSMON group name (SYSMON_GROUP) =

Client Userid-Password Plugin (CLNT_PW_PLUGIN) =
Client Kerberos Plugin (CLNT_KRB_PLUGIN) =
Group Plugin (GROUP_PLUGIN) =
GSS Plugin for Local Authorization (LOCAL_GSSPLUGIN) =
Server Plugin Mode (SRV_PLUGIN_MODE) = UNFENCED
Server List of GSS Plugins (SRVCON_GSSPLUGIN_LIST) =
Server Userid-Password Plugin (SRVCON_PW_PLUGIN) =
Server Connection Authentication (SRVCON_AUTH) = NOT_SPECIFIED
Cluster manager (CLUSTER_MGR) =

Database manager authentication (AUTHENTICATION) = SERVER
Cataloging allowed without authority (CATALOG_NOAUTH) = NO
Trust all clients (TRUST_ALLCLNTS) = YES
Trusted client authentication (TRUST_CLNTAUTH) = CLIENT
Bypass federated authentication (FED_NOAUTH) = NO

Default database path (DFTDBPATH) = /home/db2inst1

Database monitor heap size (4KB) (MON_HEAP_SZ) = AUTOMATIC
Java Virtual Machine heap size (4KB) (JAVA_HEAP_SZ) = 2048
Audit buffer size (4KB) (AUDIT_BUF_SZ) = 0
Size of instance shared memory (4KB) (INSTANCE_MEMORY) = AUTOMATIC
Backup buffer default size (4KB) (BACKBUFSZ) = 1024
Restore buffer default size (4KB) (RESTBUFSZ) = 1024

Agent stack size (AGENT_STACK_SZ) = 1024
Sort heap threshold (4KB) (SHEAPTHRES) = 0

Directory cache support (DIR_CACHE) = YES

Application support layer heap size (4KB) (ASLHEAPSZ) = 15
Max requester I/O block size (bytes) (RQRIOBLK) = 32767
Query heap size (4KB) (QUERY_HEAP_SZ) = 1000

Workload impact by throttled utilities(UTIL_IMPACT_LIM) = 10

Priority of agents (AGENTPRI) = SYSTEM
Agent pool size (NUM_POOLAGENTS) = AUTOMATIC
Initial number of agents in pool (NUM_INITAGENTS) = 0
Max number of coordinating agents (MAX_COORDAGENTS) = AUTOMATIC
Max number of client connections (MAX_CONNECTIONS) = AUTOMATIC

Keep fenced process (KEEPFENCED) = YES
Number of pooled fenced processes (FENCED_POOL) = AUTOMATIC
Initial number of fenced processes (NUM_INITFENCED) = 0

Index re-creation time and redo index build (INDEXREC) = RESTART

Transaction manager database name (TM_DATABASE) = 1ST_CONN
Transaction resync interval (sec) (RESYNC_INTERVAL) = 180

SPM name (SPM_NAME) =
SPM log size (SPM_LOG_FILE_SZ) = 256
SPM resync agent limit (SPM_MAX_RESYNC) = 20
SPM log path (SPM_LOG_PATH) =

TCP/IP Service name (SVCENAME) = db2c_db2inst1
Discovery mode (DISCOVER) = SEARCH
Discover server instance (DISCOVER_INST) = ENABLE

Maximum query degree of parallelism (MAX_QUERYDEGREE) = ANY
Enable intra-partition parallelism (INTRA_PARALLEL) = NO

Maximum Asynchronous TQs per query (FEDERATED_ASYNC) = 0

No. of int. communication buffers(4KB)(FCM_NUM_BUFFERS) = AUTOMATIC
No. of int. communication channels (FCM_NUM_CHANNELS) = AUTOMATIC
Node connection elapse time (sec) (CONN_ELAPSE) = 10
Max number of node connection retries (MAX_CONNRETRIES) = 5
Max time difference between nodes (min) (MAX_TIME_DIFF) = 60

db2start/db2stop timeout (min) (START_STOP_TIME) = 10

OK. How many tablespaces are in the backup and what is the restore command you are using?

Andy

There are a total of 10 tablespaces. The command I use is
db2 restore DB PRDXNGPS to /db2/data without rolling forward

It doesn't matter if I restore one database or just run the import of a table. I only get one 1 IO queue depth when running iostat.

thanks,

You can try setting INTRA_PARALLEL to on and using the PARALLELISM parameter on the RESTORE set to something between 2 and 10. Also try the import from multiple client at one time and see what that does.

Andy

I have tried setting intra_parallel and use the parallelism but it did not help. Apparently, the IO queue length is always at 1 and cannot go beyond that. If I run a select statement then I get more than 1 IO queue length. I am suspecting that the import process or the restore process is single threaded operation. Thank you for your help. I really appreciate it.

dbuser001