SQL1042C An unexpected system error occurred. SQLSTATE=58004

An application owner reported an error on a DB2 database connection attempt.  A query on db2diag.log returned  this message

 

ADM1710C  The database is not accessible because the DB2 database 
          manager cannot write to the log control file "SQLOGCTL.LFH.2" on 
          database partition "0".  Possible reasons for this include: the file 
          does not exist; the file is not accessible to the database manager 
          because of network, file system, or OS problems; or incorrect file 
          permissions are preventing the database manager from writing to the 
          file.  Ensure that the file is accessible to the database manager and 
          that the file system is functioning properly, and restart or 
          reconnect to the database.

 

I attempted a DB2 database database connection, with a message of:

 

SQL1042C  An unexpected system error occurred.  SQLSTATE=58004

 

The database was marked as bad .  the DB2 error messages correlated with Linux messages, relating to SCSI errors .

 

 
Dec 19 08:02:05 server1 kernel: Buffer I/O error on device dm-18, logical block 1562696
Dec 19 08:02:05 server1 kernel: lost page write due to I/O error on dm-18
Dec 19 08:02:05 server1 kernel: SCSI error : <0 0 2 0> return code = 0x20000
Dec 19 08:02:05 server1 kernel: end_request: I/O error, dev sdc, sector 12503752

 

DB2 couldn’t write  due to the Linux file system drive moving into a read-only state ,which it does under certain circumstances to protect itself . Using Commands check for read only Linux file system  , to verify the filesystem was in read only , I contact the Linux administrator.

The filesytem was remounted and placed back into the read/write state. Various DB2 files were recovered and made accessible again – which allowed the database to become available .

 Read More

Commands to check for read only Linux file system - DBA DB2

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Command to see connection on a DB2 database - list applications

Commands to check for read only Linux file system

Checking for read only on the Linux file system is required when investigating certain DB2  problems especially disk errors

For example, I  saw an error :

--from db2diag.log 
SQL1042C An unexpected system error occurred. SQLSTATE=58004 . 
--from linux logs
Dec 19 08:02:05 server1 kernel: Buffer I/O error on device dm-18, logical block 1562696
Dec 19 08:02:05 server1 kernel: lost page write due to I/O error on dm-18
Dec 19 08:02:05 server1 kernel: SCSI error : <0 0 2 0> return code = 0x20000
Dec 19 08:02:05 server1 kernel: end_request: I/O error, dev sdc, sector 12503752

 

Some root cause analysis highlighted a disk error causing a Linux mountpoint to become a read only.

Commands to check for read only Linux  file system

 

grep ‘ro’ /proc/mounts

--miss remote mounts
grep ' ro ' /proc/mounts | grep -v ':'

 Read More

Linux multipath command

DB2 and Linux IO testing tools

Display Linux CPU information

 

DIA3208E Error encountered in TCP/IP protocol support

Question : I recently received a query from an application owner, who reported application outage issue.

 An inspection of the db2diag.log file found this message. How can I solve this problem?

DIA3208E  Error encountered in TCP/IP protocol support. TCP/IP function "close". Socket was "3". Errno was "9".
 Errno was "9".

 

Answer: The DIA3208E  Error encountered in TCP/IP protocol support  message indicates multiple db2tcpcm processes. If the instance is stopping and there is an attempt to terminate the sockets simultaneously , only one can close without an error

Option 1 -   db2set DB2TCPCONNMGRS=1

Option 2 – Install DB2 version 9.5 FixPack 6

 Read More

DB2 – verify DB2 is available - DBA DB2

Locate the DB2 connection port number on Linux - DBA DB2

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DB2 - SQL1035N The database is currently in use

Question : I’m trying to complete an OFFLINE FULL BACKUP and  receive this error message when executing db2 backup DB mydb.

 SQL1035N  The database is currently in use.  SQLSTATE=57019

 I’ve checked db2 list applications  - which returns no applications .

 How can I  fix?

Answer: First , check if the database is activated.

db2pd -db mydb -app

or

db2 list active databases

Second, if it’s activated , then deactivate the database

 db2 deactivate database

Third, try OFFLINE FULL BACKUP again

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DB2 - SQL1762N Unable to connect to database because there is not enough

Question :   In the daily check of the db2diag.log files the following error message appeared. How do I fix?

 

SQL1762N  Unable to connect to database because there is not enough 
          space to allocate active log files.

 

Answer: Possible Reasons include :
1) Could be space restriction on the drive . Hint: Check for DIA8312C Disk was full.

2) Log archiving method is not working as expected

3) Userexit is not working as expected

How to Fix  - Depending on which reason
1) Free up  space on drive

2) Fix  userexit and make sure it’s working correctly.

3)  Make sure log archiving method works correctly.. This could include investigating why the backup server is not accepting sessions

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