[CALCITE-3330] propagateCostImprovements() could result in stack over… #1445
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…flow Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation.
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I have a UT failure at MongoAdapterTest.testGroupByAvgSumCount() due to the operator sequence change. My understand is this does not actually affect the plan. But would appreciate if someone is more familiar with the background can review it. Thx. |
danny0405
reviewed
Oct 10, 2019
| "{$sort: {STATE: 1}}")); | ||
| "{$sort: {STATE: 1}}", | ||
| "{$project: {STATE: 1, A: {$divide: [{$cond:[{$eq: ['$_2', {$literal: 0}]},null,'$_1']}, '$_2']}, S: {$cond:[{$eq: ['$_2', {$literal: 0}]},null,'$_1']}, C: '$_2'}}" | ||
| )); |
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I'm a little confused why the plan has changed, because this patch seems have equivalent logic function as before.
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It's possible because the sequence of cost propagation is changed now thus the memo can be different. But anyway the plan is equivalent.
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You mean the planner choose a same cost plan with before but with different structure ?
XuQianJin-Stars
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Nov 17, 2019
…ements Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation. Close apache#1445
XuQianJin-Stars
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Nov 20, 2019
…ements Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation. Close apache#1445
XuQianJin-Stars
pushed a commit
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Nov 20, 2019
…ements Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation. Close apache#1445
wangxlong
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Feb 13, 2020
…ements Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation. Close apache#1445
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…flow
Current implementation uses depth first approach for propagating cost improvements to parent rel nodes. This could lead to stack overflow if the rel node hierarchy is very deep. Fix this by using breath first approach for cost propagation.