Avoid extra allocation in OrderByOperator#getOutput()#16447
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martint merged 1 commit intotrinodb:masterfrom Mar 17, 2023
Merged
Avoid extra allocation in OrderByOperator#getOutput()#16447martint merged 1 commit intotrinodb:masterfrom
martint merged 1 commit intotrinodb:masterfrom
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martint
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Mar 8, 2023
| blocks[i] = nextPage.getBlock(outputChannels[i]); | ||
| } | ||
| return new Page(nextPage.getPositionCount(), blocks); | ||
| return nextPage.getColumns(outputChannels); |
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getColumns() calls wrapBlocksWithoutCopy(positionCount, blocks), while new Page(count, blocks) uses blocksCopyRequired = true. Have you analyzed the impact of that change in semantics?
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Yep, that's the intention behind this change. The Block[] array in the previous implementation was created locally (not shared anywhere else) but was created once and then immediately cloned by the page constructor unnecessarily. Now we only create a single copy of the blocks array inside of Page#getColumns which requires no additional copy (and makes the code a little cleaner).
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@martint - ping for review / merge |
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Description
Changes
OrderByOperator#getOutput()to usePage#getColumns(outputChannels)instead of building an array of output blocks itself, which avoids an extra allocation.Release notes
(x) This is not user-visible or docs only and no release notes are required.
( ) Release notes are required, please propose a release note for me.
( ) Release notes are required, with the following suggested text: