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ISSUES-2259 support truncate syntax #2260

Merged
merged 4 commits into from
Jun 9, 2018
Merged

ISSUES-2259 support truncate syntax #2260

merged 4 commits into from
Jun 9, 2018

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zhang2014
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@zhang2014 zhang2014 commented Apr 22, 2018 •
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#2259

CheckList

  • StorageBuffer
  • StorageCatBoostPool
  • StorageDictionary
  • StorageDistributed
  • StorageFile
  • StorageKafka
  • StorageLog
  • StorageMaterializedView
  • StorageMemory
  • StorageMerge
  • StorageMergeTree
  • StorageMySQL
  • StorageNull
  • StorageODBC
  • StorageReplicatedMergeTree
  • StorageSet
  • StorageStripeLog
  • StorageTinyLog
  • StorageView
    I hereby agree to the terms of the CLA available at: https://yandex.ru/legal/cla/?lang=en

zhang2014
zhang2014 commented Apr 22, 2018
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dbms/src/Storages/StorageMergeTree.cpp Outdated
@@ -126,6 +126,13 @@ void StorageMergeTree::drop()
data.dropAllData();
}

void StorageMergeTree::truncate()
{
shutdown();
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@alexey-milovidov shutdown is synchronous? What would I do if it wasn't ? Because I need to know when the merge task is terminated.

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It's synchronous.

@alexey-milovidov
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Please check for ReplicatedMergeTree tables. The implementation shouldn't be trivial for them.

@zhang2014
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The current idea is based on the ReplicatedMergeTreeLogEntryData::TRUNCATE_TABLE command

@zhang2014 zhang2014 force-pushed the feature/support_truncate branch 6 times, most recently from a7b8106 to ad40fcf Compare April 24, 2018 12:41
@zhang2014 zhang2014 mentioned this pull request Apr 25, 2018
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@zhang2014 zhang2014 force-pushed the feature/support_truncate branch 3 times, most recently from 00588d4 to f7fb7ab Compare May 2, 2018 01:32
@zhang2014 zhang2014 force-pushed the feature/support_truncate branch 5 times, most recently from fbdfa12 to 9db8f35 Compare May 5, 2018 16:06
@zhang2014 zhang2014 changed the title [WIP] ISSUES-2259 support truncate syntax ISSUES-2259 support truncate syntax May 5, 2018
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I'm done. Please help review the changes. @alexey-milovidov @ztlpn

@zhang2014 zhang2014 force-pushed the feature/support_truncate branch 3 times, most recently from 31c0789 to 8936d88 Compare May 5, 2018 18:13
alexey-milovidov
alexey-milovidov reviewed May 9, 2018
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dbms/src/Common/ZooKeeper/Types.h Outdated
@@ -54,6 +54,9 @@ using SetResponse = ZooKeeperImpl::ZooKeeper::SetResponse;
using ListResponse = ZooKeeperImpl::ZooKeeper::ListResponse;
using CheckResponse = ZooKeeperImpl::ZooKeeper::CheckResponse;

template <typename R>
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Missing comment.

alexey-milovidov
alexey-milovidov reviewed May 9, 2018
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dbms/src/Common/ZooKeeper/Types.h Outdated
@@ -54,6 +54,9 @@ using SetResponse = ZooKeeperImpl::ZooKeeper::SetResponse;
using ListResponse = ZooKeeperImpl::ZooKeeper::ListResponse;
using CheckResponse = ZooKeeperImpl::ZooKeeper::CheckResponse;

template <typename R>
using MultiAsyncResponse = std::vector<std::pair<std::string, std::future<R>>>;
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Bad name. It shouldn't mess up with "multi" operation in ZooKeeper.
More correct name: AsyncResponses.

alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Merging: Fixed half of problems #2260
d56c199
alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Merging: Fixed most of problems #2260
f3d8b4e
alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Merging: Fixed most of problems #2260
cfacdf1
alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Merging: Fixed most of problems, actualized test #2260
6475ea9
@alexey-milovidov alexey-milovidov merged commit 3afb335 into ClickHouse:master Jun 9, 2018
alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Databases/IDatabase.h
/// Delete metadata, the deletion of which differs from the recursive deletion of the directory, if any.
virtual void drop() = 0;
/// Delete database metadata, if exists.
virtual void drop(Context & context)
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@alexey-milovidov alexey-milovidov Jun 9, 2018 •
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Method body should be in .cpp

This method is not quite correct, because only Ordinary databases have metadata for tables as files in metadata directory. Other databases doesn't require removal of metadata from filesystem.

Creating and removing database.sql files is not the responsibility of Database itself.
For example, database doesn't create this file, so it shouldn't remove it.

Another example: tables (Storages) are not responsible for creating and removing .sql files - it is the responsibility of Database. By the same principle, Database is not responsible for creating and removing its .sql files - this is the responsibility of caller.

If this method removes internal metadata directory, why it doesn't remove internal data directory?

Fixed.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Interpreters/ClusterProxy/TruncateStreamFactory.cpp
@@ -0,0 +1,68 @@
#include <Interpreters/ClusterProxy/TruncateStreamFactory.h>
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We shouldn't proxy TRUNCATE query for Distributed table, because query ON CLUSTER already do it.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Interpreters/InterpreterDropQuery.cpp
String current_table_name = table.first->getTableName();

if (drop.detach)
else if (kind == ASTDropQuery::Kind::Truncate)
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checkTableCanBeDropped should be called for truncate, because it is equally dangerous operation.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Parsers/ASTDropQuery.h
String getID() const override { return (detach ? "DetachQuery_" : "DropQuery_") + database + "_" + table; };
String getID() const override
{
if (kind == ASTDropQuery::Kind::Drop)
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Non-trivial methods should be in .cpp.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Parsers/ASTDropQuery.h
<< (detach ? "DETACH TABLE " : "DROP TABLE ")
<< (if_exists ? "IF EXISTS " : "") << (settings.hilite ? hilite_none : "")
<< (!database.empty() ? backQuoteIfNeed(database) + "." : "") << backQuoteIfNeed(table);
settings.ostr << (settings.hilite ? hilite_keyword : "");
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Copy-paste.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/IStorage.h
/** Delete the table data. Called before deleting the directory with the data.
* If you do not need any action other than deleting the directory with data, you can leave this method blank.
*/
virtual void truncate(const ASTPtr & /*query*/)
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This comment is a copy-paste of the above. This may lead to confusion.
I've totally rewrite this comment.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/MergeTree/MergeTreeData.cpp
@@ -797,7 +797,16 @@ void MergeTreeData::dropAllData()

LOG_TRACE(log, "dropAllData: removing data from filesystem.");

Poco::File(full_path).remove(true);
std::vector<Poco::File> data_dirs;
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Motivation is unclear.

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Missing comments.

alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Reverted unclear modification #2260
ebe5e3f
alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageDistributed.cpp
}
}

ClusterProxy::TruncateStreamFactory truncate_stream_factory(cluster);
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I've removed this.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageMergeTree.cpp

void StorageMergeTree::truncate(const ASTPtr & /*query*/)
{
merger.merges_blocker.cancelForever();
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How the merges are supposed to work after truncate?

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp

if (fake_part_name.empty())
if (dropBlocksInPartition(*zookeeper, partition_id, entry, detach))
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dropParts, not Blocks.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
@@ -3808,14 +3802,18 @@ void ReplicatedMergeTreeMergeSelectingThread::clearState()
{
deduplicate = false; /// TODO: read deduplicate option from table config

uncached_merging_predicate = [this](const MergeTreeData::DataPartPtr & left, const MergeTreeData::DataPartPtr & right)
uncached_merging_predicate = [this](const MergeTreeData::DataPartPtr &left, const MergeTreeData::DataPartPtr &right)
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Accidential modification.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
{
return canMergePartsAccordingToZooKeeperInfo(left, right, storage->getZooKeeper(), storage->zookeeper_path, storage->data);
return canMergePartsAccordingToZooKeeperInfo(left,
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Accidential modification.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
};

merging_predicate_args_to_key = [](const MergeTreeData::DataPartPtr & left, const MergeTreeData::DataPartPtr & right)
merging_predicate_args_to_key = [](const MergeTreeData::DataPartPtr &left, const MergeTreeData::DataPartPtr &right)
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Accidential modification.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
{
return std::make_pair(left->name, right->name);
return std::make_pair(left->name, right->name);
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Accidential modification. Wrong indentation.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
@@ -3824,11 +3822,49 @@ void ReplicatedMergeTreeMergeSelectingThread::clearState()

now = std::chrono::steady_clock::time_point();

can_merge = [&] (const MergeTreeData::DataPartPtr & left, const MergeTreeData::DataPartPtr & right, String *)
can_merge = [&](const MergeTreeData::DataPartPtr &left, const MergeTreeData::DataPartPtr &right, String *)
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Accidential modification.

alexey-milovidov
alexey-milovidov reviewed Jun 9, 2018
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dbms/src/Storages/StorageReplicatedMergeTree.cpp
return partsWillNotBeMergedOrDisabled(left, right, storage->queue)
&& cached_merging_predicate->get(now, uncached_merging_predicate, merging_predicate_args_to_key, left, right);
return partsWillNotBeMergedOrDisabled(left, right, storage->queue)
&& cached_merging_predicate->get(now, uncached_merging_predicate, merging_predicate_args_to_key, left, right);
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Accidential modification.

alexey-milovidov added a commit that referenced this pull request Jun 9, 2018
@alexey-milovidov
Reverted unclear modification #2260
641076d
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alexey-milovidov commented Jun 9, 2018 •
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I would like to prefer different method of implementation:

There is default implementation for truncate, that simply do drop and create table under lock.
All tables will use default implementation except ReplicatedMergeTree.

Cons:

  • the lock will be in global scope, not for table scope;
  • metadata_modification_time will be updated;
  • this method is less atomic: the table may become dropped instead of truncated when server was died in the middle;

Pros:

  • simple implementation, almost no additional logic.

alexey-milovidov added a commit that referenced this pull request Jun 10, 2018
@alexey-milovidov
Removed wrong modification #2260
72af2b7
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alexey-milovidov commented Jun 10, 2018 •
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@zhang2014

Thank you! This is definitely useful feature.
What to do further... For example, our users have a request to implement
CREATE OR REPLACE for tables and especially for views.

This should be done atomically (from the client point of view). It can be done under global (context) lock.

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zhang2014 commented Jun 11, 2018 •
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@alexey-milovidov Thank for you review, I have learned a lot.
If necessary, I will continue to follow up and fix these problems, But it may be a few days later, The TCP ClickHouse JDBC Driver we implemented will be released recently : )
cc @sundy-li

@alexey-milovidov alexey-milovidov mentioned this pull request Sep 4, 2018
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@ztlpn ztlpn Awaiting requested review from ztlpn

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@zhang2014 @alexey-milovidov @ludv1x