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Diving
Into the Shared Pool - An In Depth Look at Tuning the Shared Pool (Part 2)
Oracle Tips by Mike Ault |
A Matter
Of Hashing
Long statements require special care to see
that bind variables are used to prevent this problem with hashing.
Another help for long statements is to use views to store values at
an intermediate state thus reducing the size of the variable portion
of the SQL. Notice in the example select in Figure 8 that the only
difference between the two identically hashed statements is that the
“region_code” and “region_dealer_num” comparison values are
different, if bind variables had been used in these statements there
would only have been one entry instead of two.
Guideline 6: Use bind variables, PL/SQL
(procedures or functions) and views to reduce the size of large SQL
statements to prevent hashing problems.
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