Fix race conditions in CREATE/DROP of different replicas of ReplicatedMergeTree#11592
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alexey-milovidov merged 4 commits intomasterfrom Jun 11, 2020
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PVS Ok. |
alesapin
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I think it's quite a complicated solution, but I cannot propose something simpler. It will not work between concurrent drop/create between different versions but it's OK.
| else if (code == Coordination::ZNOTEMPTY) | ||
| { | ||
| throw Exception(fmt::format( | ||
| "The old table was not completely removed from ZooKeeper, {} still exists and may contain some garbage.", zookeeper_path), ErrorCodes::TABLE_WAS_NOT_DROPPED); |
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How it's possible? We create both zookeeper_path and it's content in a single transaction bellow. It can be empty or doesn't exist.
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I think that it's not possible. And it does not reproduce in test.
I will change to code to LOGICAL_ERROR.
| ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path, "", zkutil::CreateMode::Persistent)); | ||
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| /// Check that the table is not being dropped right now. | ||
| ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/dropped", "", zkutil::CreateMode::Persistent)); |
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interesting way to check that node doesn't exist)
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Yes, and I did not invent it :) It's already used in other places in code.
tavplubix
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Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Fix race conditions in CREATE/DROP of different replicas of ReplicatedMergeTree. Continue to work if the table was not removed completely from ZooKeeper or not created successfully. This fixes #11432.
Detailed description / Documentation draft:
See https://clickhouse-test-reports.s3.yandex.net/11580/e2c6d090192d870edffc40e40deeb4c14417e5be/functional_stateless_tests_(thread)/test_run.txt.out.log