Solve I_S queries using CNF rewriting #7677
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Signed-off-by: GuptaManan100 <manan@planetscale.com>
Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Andres Taylor <andres@planetscale.com>
|
@pontusmelke am I doing it right? ;) |
Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Andres Taylor <andres@planetscale.com>
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We could use this strategy in more situations - we could replan when we encounter Scatter queries, vtgate joins and probably some more. |
Signed-off-by: Andres Taylor <andres@planetscale.com>
harshit-gangal
approved these changes
Mar 17, 2021
Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Andres Taylor <andres@planetscale.com>
Still got it 💥 |
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Description
To handle I_S queries correctly, we need to be able to find the
table_schemaandtable_namepredicates in the WHERE clause. Sometimes, this is difficult because of how the query is written.What this PR does is to introduce a rewriter that is able to massage boolean logic into a simpler form. It normalises the predicates into a form that the planner is looking for, and this makes it possible for the planner to find more applicable rules.
CNF, short for conjuctive normal form, rewrites the predicates into
an AND of ORs, which is exactly what the planner is looking for.Related Issue(s)
Fixes: #7377
Checklist
NopeAddedNot neededImpacted Areas in Vitess
Components that this PR will affect: