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https://issues.jboss.org/browse/TEIID-1726?page=com.atlassian.jira.plugin...
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Steven Hawkins commented on TEIID-1726:
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There is a lot more detail that is needed for this issue. For review the current
approaches to source hints are:
1. use the execution payload to associate an Oracle hint with the source query. Requires
JDBC client interaction and is only useful in situations where the hint is applicable to
all Oracle source queries from that user query. This would typically be single source
usage. From a general perspective the drawbacks are - requires JDBC logic, it's
oracle specific, you have no control over the hint positioning, you have no control over
which source queries receive the hint.
2. Modify table name in source values to include hints. The drawbacks are - hint position
will be in the from clause, a valid source query may not be created in some update
situations, and the hint is always applied regardless of the situation.
3. Customize the translator to look for known situations where hints are applicable. The
drawback is that custom code is required.
Alternatives or possible enhancements to the above include:
1. Implement the native query feature. This would allow the user to embed the appropriate
SQL at the physical model or possibly to issue a direct invocation through a procedure.
The drawbacks here are that native query physical tables would still always apply the hint
and procedures inhibit encapsulation.
2. Add a hint container with the ability to specify translator names and/or possibly
nodeids/table aliases (form the source plans), e.g.
/*+ sh oracle:... 10:... */ SELECT ...
We would then ensure that relevant translators would append the hints. Source validation
would be needed to ensure that SQL is not being injected. Drawbacks here include that
node ids can change whenever the source plan is different, and relying just on translator
names is not sufficient to distinguish multiple queries sent to the same source.
3. Have each hint application scenario addressed as an enhancement utilizing extension
metadata. If the user can describe the hint and the situation when it should be applied,
then we could add metadata/translator logic to automatically handle the case - or at least
apply the hint when certain extension metadata is present and the source query has a known
form.
Feedback will help determine what path(s) should be taken.
Requesting ability to add/use Oracle hints in EDS
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Key: TEIID-1726
URL:
https://issues.jboss.org/browse/TEIID-1726
Project: Teiid
Issue Type: Feature Request
Components: Server
Affects Versions: 7.4.1
Reporter: Debbie Steigner
Requesting the ability to use Oracle hints inside virtual transformations and enduser
queries in EDS and Teiid Designer
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