[Xapian-tickets] [Xapian] #752: Segmentation fault in matcher/queryoptimiser
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nobody at xapian.org
Wed Aug 9 05:46:56 BST 2017
#752: Segmentation fault in matcher/queryoptimiser
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Reporter: rsto | Owner: olly
Type: defect | Status: assigned
Priority: normal | Milestone: 1.4.5
Component: Matcher | Version: git master
Severity: normal | Resolution:
Keywords: | Blocked By:
Blocking: | Operating System: All
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Comment (by olly):
I've compared the current approach of handing over ownership of the hint
to the `QueryOptimiser` object with just setting the hint to `NULL` in
situations where it might be invalidated.
The differences each way in my tests were very small, and similar in size
but in opposite directions. As you'd expect, handing over ownership
incurs a little extra overhead; but the gain in a small-scale test for the
hint being set when it gets used was also small.
I think the conclusion is actually to keep the ownership mechanism -
although it didn't give us a big gain in my tests, those were small scale
tests and the gain with a larger database should be greater, while
overhead for tracking ownership is essentially fixed. The key point is
really that that we pay a small fixed cost which can save us nothing to
lots.
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Ticket URL: <https://trac.xapian.org/ticket/752#comment:4>
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