Improve memory consumption by using static child canceller callback without binding to parent promise #117
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jsor
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May 4, 2018
src/Promise.php
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| if ($this->requiredCancelRequests <= 0) { | ||
| $this->cancel(); | ||
| return new static($this->resolver($onFulfilled, $onRejected, $onProgress), self::parentCancellerFunction($parent)); } |
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CS: missing linebreak before the closing } of the method
This was referenced May 4, 2018
jsor
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May 6, 2018
WyriHaximus
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This incorporates the work done by @clue in the following PR's for reactphp/promise: * reactphp/promise#115 * reactphp/promise#116 * reactphp/promise#117 * reactphp/promise#118 * reactphp/promise#119 Co-authored-by: Christian Lück <christian@lueck.tv>
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This incorporates the work done by @clue in the following PR's for reactphp/promise: * reactphp/promise#113 * reactphp/promise#115 * reactphp/promise#116 * reactphp/promise#117 * reactphp/promise#118 * reactphp/promise#119 Co-authored-by: Christian Lück <christian@lueck.tv>
This was referenced Jun 9, 2018
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Calling
cancel()on a child promise that follows its parent promise now no longer causes a cyclic garbage reference in any exception trace as discussed in #46. This builds on top of the implementation approach in #115 and #116 and the ideas discussed in #46.The gist here is that
$promise->then()->cancel()now no longer causes any unexpected cyclic garbage reference and consumers of this package do not need to take special care of this.Similar patches have been introduced with #115 and #116 to implement a similar logic for the resolution and cancellation callbacks and this PR takes advantage of this for its internal implementation.
Invoking the benchmarking example from #113 shows no effect because it does not use child promises. After patching this to use
$promise->then()->cancel()instead of$promise->cancel(), this shows a very significant performance and memory improvement! Initially this peaked somewhere around 15 MB on my system taking 24s. After applying this patch, this script reports a constant memory consumption of around 0.6 MB taking 5s.This PR actually includes a test that shows how garbage memory references are no longer an issue in any supported PHP version and how cancelling a child promise no longer causes any such references on its own (this means that this requires no effort on the consumer side).