Six Things a DBA Should Knowdownloads.actian.com/online/media/pdf/Education... · A DBA should be...
Transcript of Six Things a DBA Should Knowdownloads.actian.com/online/media/pdf/Education... · A DBA should be...
Six Things a DBA Should Know
Six things a DBA should know
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Six things a DBA should know
Backup Restore Data Security Query Tuning Monitoring Instance Maintenance
Backup
Should be well understood Should be run on a regular basis and on
demand Enable recovery from unexpected issues
– Hardware failures– Disasters– Corruption due to user error
In addition recovery from– Bad application upgrades– Rollback patches
Backup
The most common problems– Insufficient disk space– Changes not journalled– Backup incomplete– Backup unreadable– Untested recovery
Backup
Ingres solutions– ckpdb– unloaddb– copydb– relocatedb– OS level backup
• Tar • CPIO• Backup• Etc.
– Replication
Restore
A Backup is – One half, a restore is the other– Useless if the data cannot be recovered
Very visible as restores required when– Things are down– In bad shape
Being unable to perform a restore is a career limiting move
Restore
No excuse for not being able to do a restore for• Production systems• The most esoteric restores• Partials• Point in time• Etc.
Practice and be prepared Third party products A restore may be done under pressure Do a successful restore and be a hero
Restore
Ingres supports– rollforwarddb– unloaddb– copydb– OS level backup
• Tar • CPIO• Backup• Etc.
Data Security
Insecure database objects, insecure data Often database security is lax due to
– Applications needing access to common objects– Ignorance– Laziness
Understand the needs– Some tables may be read only– Auditing tables
• Only inserts and selects• Not updates or deletes
Data Security
If data were money, how should it be treated? Give access only to the required data Access might be limited through
– Database procedures– Views
Data Security
Ingres supports– Permits– Grants– Roles– Groups– Database procedures– Views– Security auditing– Security alarms
Query Tuning
Tuning queries is a core skill for a DBA Many DBAs don't know how to
– Read a query plan– Choose a table structure– Create an index in parallel– Tune a query
Not everybody can be – Itzik Ben-Gan and tweak code – Joe Celko and write complex queries
Query Tuning
A DBA should know how to – Reading query plans– Indexing– Determining which indexes are used– Choosing the table structure– Optimization statistics
Performance tuning is– An art as much as a science– It takes experience to do it well
Query Tuning
Ingres supports– printqry– qep– trace point qe90– io_trace– lock_trace– optimizeonly– joinop [no]timeout– joinop [no]greedy– parallel
Monitoring
Systems have performance issues A DBA should be able to explain if
– There is a performance problem– Things are really busy– This is a symptom of a bigger issues
Using– DBMS tools– Performance Monitor tools– System tools
Monitoring
A DBA should be able to determine – If the problem is
• Hardware• Application• DBMS
– What's wrong– How to fix it
Monitoring
Ingres provides– Visual DBA– Visual Performance Monitor– Performance Monitor Wizard– Cache Statistics Monitor– IPM– iimonitor statistics– IMA– Logstat– Lockstat– Trace Points
Instance Maintenance In addition to database backup and restore
– Monitoring disk space usage– Moving objects for better performance– Adding and removing users
Instance tuning– Server monitoring– Changing configuration parameter– Adding or removing servers
Checking database integrity– Verifying system catalogues– Reviewing error and system log
Instance problems
Identify Create a test case Report Apply a patch as needed
Instance Maintenance
Ingres provides– Trace points– verifydb– iimonitor– Ingres Configuration Manager– Configuration By Forms– infodb– extenddb– usermod– sysmod– syscheck
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