Edit report at https://bugs.php.net/bug.php?id=60836&edit=1
ID: 60836
Comment by: phristen at yahoo dot com
Reported by: oliver at hofff dot com
Summary: Improve array_intersect_key performance
Status: Open
Type: Feature/Change Request
Package: Arrays related
PHP Version: Irrelevant
Block user comment: N
Private report: N
New Comment:
Actually sorry, it does make sense...
But it's easily solvable. Just run the shortest array against the first array
(unless they happen to be the same) to get the values, then run the result
against the rest of them.
Previous Comments:
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[2012-03-25 17:27:58] phristen at yahoo dot com
carloschilazo, what you said doesn't make sense.
Intersecting A, B, and C will produce the same result as intersecting C, B, and
A, or any other combination of the operands.
Unfortunately, a lot of PHP array functions are known to be extremely
inefficient :(
------------------------------------------------------------------------
[2012-01-27 03:52:11] carloschilazo at gmail dot com
we cant start walking the shortest array given, because we first need to know
which elements we need to look in the other arrays, and those are the ones
presesnt in the first array
" returns an array containing all the entries of array1 which have keys that
are
present in all the arguments. "
------------------------------------------------------------------------
[2012-01-22 00:34:49] oliver at hofff dot com
Description:
------------
The trivial test script below runs longer than the extpected "instant"
execution (lot longer).
This is because the algorithm walks the first argument and looks up the key in
every other array supplied as an argument.
Instead it should walk the shortest array given, and look up the keys in every
other array.
Maybe this issue or similar ones also apply to other array functions, which
perform set operations, but I have not checked the code of them.
Of course the optimization could be done in userland, but that feels not right.
Test script:
---------------
$arr = array_fill(0, 1000000, '...');
$i = 1000;
while($i--) {
array_intersect_key($arr, array());
}
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Edit this bug report at https://bugs.php.net/bug.php?id=60836&edit=1
