Calling "SELECT t.* from <table> AS t" to get meta information is too expensive
for big tables
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Key: MAPREDUCE-1224
URL: https://issues.apache.org/jira/browse/MAPREDUCE-1224
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: contrib/sqoop
Affects Versions: 0.20.1
Environment: all platforms, generic jdbc driver
Reporter: Spencer Ho
The SqlManager uses the query, "SELECT t.* from <table> AS t" to get table spec
is too expensive for big tables, and it was called twice to generate column
names and types. For tables that are big enough to be map-reduced, this is too
expensive to make sqoop useful.
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