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Module 17: A Tale of Three Tables
After completing this module, you will be able to:
Analyze the efficiency of backup procedures after a
single disk failure.
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Permanent Journal Scenario
A Tale of Three Tables
A user has three data tables:
Table X Fallback
Before and
After Image JournalsTable Y No Fallback
No Before and
Dual After Image JournalsTable Z No Fallback
Single Before and
Single After Image Journals
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Table X
Fallback protected data
Fallback protected before images
Fallback protected after images
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X Table X
Primary Primary Primary Primary1 2 3 4
Table X Table X Table X Table X
Fallback Fallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
After After After After
1 2 3 4
After After After After
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Before Before Before Before
1 2 3 4
Before Before Before Before
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Data
PJ
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Table Y
No fallback
Dual after image
AMP 1 AMP 2 AMP 3 AMP 4
Table Y Table Y Table Y Table Y
Primary Primary Primary Primary1 2 3 4
After After After After
1 2 3 4
After After After After
2 3 4 1
Data
PJ
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Table Z
No fallback
Single before images
Single after images
AMP 1 AMP 2 AMP 3 AMP 4
Table Z Table Z Table Z Table ZPrimary Primary Primary Primary
1 2 3 4
Before Before Before Before
1 2 3 4
After After After After
2 3 4 1
Data
PJ
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Permanent Journals(Putting all tables three together)
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X Table X
Primary Primary Primary Primary1 2 3 4
Table X Table X Table X Table XFallback Fallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
After After After After1 2 3 4
After After After After2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Before Before Before Before1 2 3 4
Before Before Before Before2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Table Y Table Y Table Y Table YPrimary Primary Primary Primary
1 2 3 4
After After After After
1 2 3 4After After After After
2 3 4 1
Table Z Table Z Table Z Table ZPrimary Primary Primary Primary
1 2 3 4
Before Before Before Before1 2 3 4
After After After After2 3 4 1
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Archive Policy
DAILY
CHECKPOINT ALL JOURNALS with SAVE
ARCHIVE JOURNAL TABLES
DELETE SAVED JOURNALS
ARCHIVE One Complete Table per Day
WEEKLY
Perform ALL-AMPs ARCHIVE of DATA TABLES
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Archive Scenario
Monday:Archive journals X, Y and Z
Archive table X
Tuesday:
Archive journals X, Y and ZArchive table Y
Wednesday:
Archive journals X, Y and Z
Archive table Z
Thursday:
AMP 3: Two drives fail in a drive group
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After Restart Processing Completes
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X
Primary Primary Primary1 2 4
Table X Table X Table XFallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 3
After After After1 2 4
After After After2, 3, 4 1, 3, 4 1, 2, 3
Before Before Before1 2 4
Before Before Before2, 3, 4 1, 3, 4 1, 2, 3
Table Y Table Y Table YPrimary Primary Primary
1 2 4
After After After
1 2 4After After After
2 3 1
Table Z Table Z Table ZPrimary Primary Primary
1 2 4
Before Before Before1 2 4
After After After2 3 1
1. Replace the 2 drives.2. Initialize the rank.
3. Format the array
(RAID 1 or 5).
4. Initialize and rebuild
the AMPs Vdisk
using Vprocmanager
functions (e.g.,
BOOT).
5. Use the table
REBUILD utility to
rebuild AMP 3 - the
VprocState will be
UTILITY during this
phase.
7. REBUILD will set the
VprocState to
ONLINE when
finished.
8. Restart Teradata.
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After REBUILD and Restart of Teradata
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X Table X
Primary Primary Primary Primary1 2 3 4
Table X Table X Table X Table XFallback Fallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
After After After After1 2 3 4
After After After After2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Before Before Before Before1 2 3 4
Before Before Before Before2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Table Y Table Y Table Y Table YPrimary Primary (Header) Primary
1 2 4
After After After After
1 2 3 4After After After After
2 3 4 1
Table Z Table Z Table Z Table ZPrimary Primary Primary
1 2 4
Before Before Before1 2 4
After After After2 3 1
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Table X Recovery
Fallback protected data
Fallback protected before images
Fallback protected after images
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X Table X
Primary Primary Primary Primary
1 2 3 4
Table X Table X Table X Table X
Fallback Fallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
After After After After
1 2 3 4
After After After After
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Before Before Before Before
1 2 3 4
Before Before Before Before
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Data
PJ
Fully Recovered
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Table Y Recovery
Before
Recovery:
AMP 1 AMP 2 AMP 3 AMP 4
Table Y Table Y Table Y Table YPrimary Primary (Header) Primary1 2 4
After After After After1 2 3 4
After After After After2 3 4 1
Data
PJ
1. Specific AMP RESTORE of Tuesdays ARCHIVE of Table Y.
2. Do NOT release utility locks.
3. RESTORE of Wednesdays ARCHIVE of journal Y.
4. Specific AMP ROLLFORWARD USE RESTORED journal of Table Y.
5. DELETE RESTORED JOURNAL Y.
6. Specific AMP ROLLFORWARD USE CURRENT journal of Table Y.
7. RELEASE utility LOCKs.
After
Recovery:
AMP 1 AMP 2 AMP 3 AMP 4
Table Y Table Y Table Y Table YPrimary Primary Primary Primary
1 2 3 4
After After After After1 2 3 4
After After After After2 3 4 1
Data
PJ
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Table Z Recovery
Before
Recovery:
AMP 1 AMP 2 AMP 3 AMP 4
Table Z Table Z Table Z Table ZPrimary Primary (Header) Primary1 2 4
Before Before Before1 2 4
After After After2 3 1
Data
PJ
1. Specific AMP RESTORE of Wednesday's ARCHIVE of Table Z.
2. Do NOT release utility locks.
3. Specific AMP ROLLFORWARD USE CURRENT journal of Table Z.
4. Perform all-AMPs ARCHIVE of Table Z.
5. Run CHECKPOINT WITH SAVE and DELETE SAVED JOURNAL.
6. RELEASE utility LOCKs.
After
Recovery:
AMP 1 AMP 2 AMP 3 AMP 4
Table Z Table Z Table Z Table ZPrimary Primary Primary Primary
1 2 3 4
Data
PJ
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After Recovery
AMP 1 AMP 2 AMP 3 AMP 4
Table X Table X Table X Table X
Primary Primary Primary Primary1 2 3 4
Table X Table X Table X Table XFallback Fallback Fallback Fallback
2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
After After After After1 2 3 4
After After After After2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Before Before Before Before1 2 3 4
Before Before Before Before2, 3, 4 1, 3, 4 1, 2, 4 1, 2, 3
Table Y Table Y Table Y Table YPrimary Primary Primary Primary
1 2 3 4
After After After After
1 2 3 4After After After After
2 3 4 1
Table Z Table Z Table Z Table ZPrimary Primary Primary Primary
1 2 3 4
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Summary
Fallback Tables Data is fully recoverable.
Dual Image Journals Journals play no part in recovery.
No Fallback Tables Data is partially available.
Dual Image Journals Data and journals is fully recoverable.
No Fallback Tables Data is partially available.
Single Image Journals Data is recoverable, but journals are lost.
No Fallback Tables Data is partially available.
No Journals Data can be recovered only to the point of the
last archive.
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