Details
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Improvement
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Resolution: Unresolved
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Major - P3
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None
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2.8.0-rc1
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None
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Query Optimization
Description
The mongodb regex parser cannot create accurate bounds to allow indexed lookups when the regex includes the "|" character. This was allowed previously, but could lead to incorrect results.
Original Description
I've got a database with 14 mio rows representing an imaginary "file system". There are (amongst others) the fields "type" (only "folder" or "file"), "folder" and "filename".
I now try this:
{
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type:'folder',
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folder:/^example1/
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}
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|
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Very fast. No results - as expected. In fact, no rows even start with "example".
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I now try this:
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{
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type:'folder',
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folder:/^example2/
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}
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Very fast, too. No results again - as expected.
Now, I try this:
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{
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type:'folder',
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folder:/^example(1|2)/
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}
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This query never returns. The whole database becomes horribly slow to the point of being unusable. I cannot even run any other queries. This used to work on 2.4.x. Why? 
Attachments
Issue Links
- is duplicated by
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SERVER-22939 A regular expression with an escaped pipe '|' character is treated as non-simple
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- related to
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