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GeekInterview.com > Interview Questions > Data Warehousing > DataStage
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Question: What are Static Hash files and Dynamic Hash files?
Answer: As the names itself suggest what they mean. In general we use Type-30 dynamic Hash files. The Data file has a default size of 2Gb and the overflow file is used if the data exceeds the 2GB size. |
| May 05, 2007 12:47:24 |
#2 |
| gagan8877 |
Member Since: May 2007 Total Comments: 8 |
RE: What are Static Hash files and Dynamic Hash files?...
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Dynamic Hash Files can automatically adjust their sie - modulous (no. of groups) and separation (group size) based on the incoming data. Type 30 are dynamic.
Static files do not adjust their modulous automatically and are best when data is static.
Overflow groups are used when the data row size is equal to or greater than the specified Large Record size in dynamic HFs.
Since Static HFs do not create hashing groups automatically, when the group cannot accomodate a row it goes to overflow.
Overflows should be minized as much as possible to optimal performance. |
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