How long ROW ID is?

64 Bits...
AMP receives 32 bit hash value and row data from PE. AMP then append a 32 bit unique value to row HASH to make 64 bit ROW ID.
ROW ID is used to sort rows in AMP.

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Teradata performance tuning and optimization steps?

1. collecting statistics
2. Explain Statements
3. Avoid Product Joins when possible
4. select appropriate primary index to avoid skewness in storage
5. Avoid Redistribution when possible
6. Use sub-selects instead of big "IN" lists
7. Use derived tables
8. Use GROUP BY instead of DISTINCT ( GROUP BY sorts the data locally on the VPROC. DISTINCT sorts the data after it is redistributed)
9. Use Compression on large tables.

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What is TENACITY? What is its default value?

TENACITY specifies the amount of time in hours, to retry to obtain a loader slot or to establish all requested sessions to logon.
The default for Fast Load is “no tenacity”, meaning that it will not retry at all.
If several FastLoad jobs are executed at the same time, we recommend setting the TENACITY to 4, meaning that the system will continue trying to logon for the number of sessions requested for up to four hours.

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what is FALLBACK in teradata?

FALLBACK is a table protection feature used in case an AMP fails. You can use FALLBACK on all tables.
FALLBACK tables use twice as much disk space as NON-FALLBACK rows

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PERM space is a pre allocated space? True/ False?

False. PERM space is not pre allocated space. its a maximum allowed space
to user or a database.

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what is the use of TEMP space?

TEMPORARY (TEMP) space :
A database may or may not have TEMP space, however, it is required if Global Temporary Tables are used.

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what is FILLER command in Teradata?

while running Fastload or Multiload if you dont want to load a particular field from the datafile to the target
table then use the FILLER command to achieve.

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