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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.