Merge branch 'master' into fix-access-gtest-in-arcadia

This commit is contained in:
Nikolai Kochetov 2021-08-10 16:13:11 +03:00 committed by GitHub
commit 8613cfd4e2
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26 changed files with 333 additions and 43 deletions

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@ -43,10 +43,10 @@ CREATE DATABASE mysql ENGINE = MaterializedMySQL('localhost:3306', 'db', 'user',
**Settings on MySQL-server side**
For the correct work of `MaterializeMySQL`, there are few mandatory `MySQL`-side configuration settings that should be set:
For the correct work of `MaterializedMySQL`, there are few mandatory `MySQL`-side configuration settings that should be set:
- `default_authentication_plugin = mysql_native_password` since `MaterializeMySQL` can only authorize with this method.
- `gtid_mode = on` since GTID based logging is a mandatory for providing correct `MaterializeMySQL` replication. Pay attention that while turning this mode `On` you should also specify `enforce_gtid_consistency = on`.
- `default_authentication_plugin = mysql_native_password` since `MaterializedMySQL` can only authorize with this method.
- `gtid_mode = on` since GTID based logging is a mandatory for providing correct `MaterializedMySQL` replication. Pay attention that while turning this mode `On` you should also specify `enforce_gtid_consistency = on`.
## Virtual columns {#virtual-columns}

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@ -125,6 +125,44 @@ Result:
└───────────────────────────┘
```
## subBitmap {#subBitmap}
Creates a subset of bitmap limit the results to `cardinality_limit` with offset of `offset`.
**Syntax**
``` sql
subBitmap(bitmap, offset, cardinality_limit)
```
**Arguments**
- `bitmap` [Bitmap object](#bitmap_functions-bitmapbuild).
- `offset` the number of offsets. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
- `cardinality_limit` The subset cardinality upper limit. Type: [UInt32](../../sql-reference/data-types/int-uint.md).
**Returned value**
The subset.
Type: `Bitmap object`.
**Example**
Query:
``` sql
SELECT bitmapToArray(subBitmap(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]), toUInt32(10), toUInt32(10))) AS res;
```
Result:
``` text
┌─res─────────────────────────────┐
│ [10,11,12,13,14,15,16,17,18,19] │
└─────────────────────────────────┘
```
## bitmapContains {#bitmap_functions-bitmapcontains}
Checks whether the bitmap contains an element.

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@ -88,6 +88,30 @@ SELECT bitmapToArray(bitmapSubsetLimit(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12
│ [30,31,32,33,100,200,500] │
└───────────────────────────┘
## subBitmap {#subBitmap}
将位图跳过`offset`个元素,限制大小为`limit`个的结果转换为另一个位图。
subBitmap(bitmap, offset, limit)
**参数**
- `bitmap` 位图对象.
- `offset` 跳过多少个元素.
- `limit` 子位图基数上限.
**示例**
``` sql
SELECT bitmapToArray(subBitmap(bitmapBuild([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]), toUInt32(10), toUInt32(10))) AS res
```
```text
┌─res─────────────────────────────┐
│ [10,11,12,13,14,15,16,17,18,19] │
└─────────────────────────────────┘
```
## bitmapContains {#bitmapcontains}
检查位图是否包含指定元素。

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@ -1,3 +1,6 @@
#include <string>
#include "Common/MemoryTracker.h"
#include "Columns/ColumnsNumber.h"
#include "ConnectionParameters.h"
#include "QueryFuzzer.h"
#include "Suggest.h"
@ -100,6 +103,14 @@
#pragma GCC optimize("-fno-var-tracking-assignments")
#endif
namespace CurrentMetrics
{
extern const Metric Revision;
extern const Metric VersionInteger;
extern const Metric MemoryTracking;
extern const Metric MaxDDLEntryID;
}
namespace fs = std::filesystem;
namespace DB
@ -524,6 +535,18 @@ private:
{
UseSSL use_ssl;
MainThreadStatus::getInstance();
/// Limit on total memory usage
size_t max_client_memory_usage = config().getInt64("max_memory_usage_in_client", 0 /*default value*/);
if (max_client_memory_usage != 0)
{
total_memory_tracker.setHardLimit(max_client_memory_usage);
total_memory_tracker.setDescription("(total)");
total_memory_tracker.setMetric(CurrentMetrics::MemoryTracking);
}
registerFormats();
registerFunctions();
registerAggregateFunctions();
@ -2581,6 +2604,7 @@ public:
("opentelemetry-tracestate", po::value<std::string>(), "OpenTelemetry tracestate header as described by W3C Trace Context recommendation")
("history_file", po::value<std::string>(), "path to history file")
("no-warnings", "disable warnings when client connects to server")
("max_memory_usage_in_client", po::value<int>(), "sets memory limit in client")
;
Settings cmd_settings;

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@ -68,7 +68,7 @@
html, body
{
/* Personal choice. */
font-family: Sans-Serif;
font-family: Liberation Sans, DejaVu Sans, sans-serif, Noto Color Emoji, Apple Color Emoji, Segoe UI Emoji;
background: var(--background-color);
color: var(--text-color);
}
@ -96,11 +96,16 @@
.monospace
{
/* Prefer fonts that have full hinting info. This is important for non-retina displays.
Also I personally dislike "Ubuntu" font due to the similarity of 'r' and 'г' (it looks very ignorant).
*/
Also I personally dislike "Ubuntu" font due to the similarity of 'r' and 'г' (it looks very ignorant). */
font-family: Liberation Mono, DejaVu Sans Mono, MonoLisa, Consolas, Monospace;
}
.monospace-table
{
/* Liberation is worse than DejaVu for block drawing characters. */
font-family: DejaVu Sans Mono, Liberation Mono, MonoLisa, Consolas, Monospace;
}
.shadow
{
box-shadow: 0 0 1rem var(--shadow-color);
@ -325,8 +330,8 @@
<span id="toggle-dark">🌑</span><span id="toggle-light">🌞</span>
</div>
<div id="data_div">
<table class="monospace shadow" id="data-table"></table>
<pre class="monospace shadow" id="data-unparsed"></pre>
<table class="monospace-table shadow" id="data-table"></table>
<pre class="monospace-table shadow" id="data-unparsed"></pre>
</div>
<svg id="graph" fill="none"></svg>
<p id="error" class="monospace shadow">

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@ -579,6 +579,37 @@ public:
}
}
UInt64 rb_offset_limit(UInt64 offset, UInt64 limit, RoaringBitmapWithSmallSet & r1) const
{
if (limit == 0 || offset >= size())
return 0;
if (isSmall())
{
UInt64 count = 0;
UInt64 offset_count = 0;
auto it = small.begin();
for (;it != small.end() && offset_count < offset; ++it)
++offset_count;
for (;it != small.end() && count < limit; ++it, ++count)
r1.add(it->getValue());
return count;
}
else
{
UInt64 count = 0;
UInt64 offset_count = 0;
auto it = rb->begin();
for (;it != rb->end() && offset_count < offset; ++it)
++offset_count;
for (;it != rb->end() && count < limit; ++it, ++count)
r1.add(*it);
return count;
}
}
UInt64 rb_min() const
{
if (isSmall())

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@ -44,6 +44,13 @@ void Block::initializeIndexByName()
}
void Block::reserve(size_t count)
{
index_by_name.reserve(count);
data.reserve(count);
}
void Block::insert(size_t position, ColumnWithTypeAndName elem)
{
if (position > data.size())
@ -287,6 +294,7 @@ std::string Block::dumpIndex() const
Block Block::cloneEmpty() const
{
Block res;
res.reserve(data.size());
for (const auto & elem : data)
res.insert(elem.cloneEmpty());
@ -364,6 +372,8 @@ Block Block::cloneWithColumns(MutableColumns && columns) const
Block res;
size_t num_columns = data.size();
res.reserve(num_columns);
for (size_t i = 0; i < num_columns; ++i)
res.insert({ std::move(columns[i]), data[i].type, data[i].name });
@ -381,6 +391,8 @@ Block Block::cloneWithColumns(const Columns & columns) const
throw Exception("Cannot clone block with columns because block has " + toString(num_columns) + " columns, "
"but " + toString(columns.size()) + " columns given.", ErrorCodes::LOGICAL_ERROR);
res.reserve(num_columns);
for (size_t i = 0; i < num_columns; ++i)
res.insert({ columns[i], data[i].type, data[i].name });
@ -393,6 +405,8 @@ Block Block::cloneWithoutColumns() const
Block res;
size_t num_columns = data.size();
res.reserve(num_columns);
for (size_t i = 0; i < num_columns; ++i)
res.insert({ nullptr, data[i].type, data[i].name });

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@ -152,6 +152,7 @@ public:
private:
void eraseImpl(size_t position);
void initializeIndexByName();
void reserve(size_t count);
/// This is needed to allow function execution over data.
/// It is safe because functions does not change column names, so index is unaffected.

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@ -31,6 +31,10 @@ SRCS(
MySQL/PacketsProtocolText.cpp
MySQL/PacketsReplication.cpp
NamesAndTypes.cpp
PostgreSQL/Connection.cpp
PostgreSQL/PoolWithFailover.cpp
PostgreSQL/Utils.cpp
PostgreSQL/insertPostgreSQLValue.cpp
PostgreSQLProtocol.cpp
QueryProcessingStage.cpp
Settings.cpp

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@ -49,6 +49,7 @@ SRCS(
TTLUpdateInfoAlgorithm.cpp
copyData.cpp
finalizeBlock.cpp
formatBlock.cpp
materializeBlock.cpp
narrowBlockInputStreams.cpp

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@ -13,6 +13,7 @@ void registerFunctionsBitmap(FunctionFactory & factory)
factory.registerFunction<FunctionBitmapToArray>();
factory.registerFunction<FunctionBitmapSubsetInRange>();
factory.registerFunction<FunctionBitmapSubsetLimit>();
factory.registerFunction<FunctionBitmapSubsetOffsetLimit>();
factory.registerFunction<FunctionBitmapTransform>();
factory.registerFunction<FunctionBitmapSelfCardinality>();

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@ -460,9 +460,24 @@ public:
}
};
struct BitmapSubsetOffsetLimitImpl
{
public:
static constexpr auto name = "subBitmap";
template <typename T>
static void apply(
const AggregateFunctionGroupBitmapData<T> & bitmap_data_0,
UInt64 range_start,
UInt64 range_end,
AggregateFunctionGroupBitmapData<T> & bitmap_data_2)
{
bitmap_data_0.rbs.rb_offset_limit(range_start, range_end, bitmap_data_2.rbs);
}
};
using FunctionBitmapSubsetInRange = FunctionBitmapSubset<BitmapSubsetInRangeImpl>;
using FunctionBitmapSubsetLimit = FunctionBitmapSubset<BitmapSubsetLimitImpl>;
using FunctionBitmapSubsetOffsetLimit = FunctionBitmapSubset<BitmapSubsetOffsetLimitImpl>;
class FunctionBitmapTransform : public IFunction
{

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@ -1091,7 +1091,14 @@ void AsynchronousMetrics::update(std::chrono::system_clock::time_point update_ti
{
sensor_file->rewind();
Int64 temperature = 0;
readText(temperature, *sensor_file);
try
{
readText(temperature, *sensor_file);
}
catch (const ErrnoException & e)
{
LOG_DEBUG(&Poco::Logger::get("AsynchronousMetrics"), "Hardware monitor '{}', sensor '{}' exists but could not be read, error {}.", hwmon_name, sensor_name, e.getErrno());
}
if (sensor_name.empty())
new_values[fmt::format("Temperature_{}", hwmon_name)] = temperature * 0.001;

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@ -21,6 +21,7 @@ SRCS(
ASTCreateRowPolicyQuery.cpp
ASTCreateSettingsProfileQuery.cpp
ASTCreateUserQuery.cpp
ASTDatabaseOrNone.cpp
ASTDictionary.cpp
ASTDictionaryAttributeDeclaration.cpp
ASTDropAccessEntityQuery.cpp
@ -95,6 +96,7 @@ SRCS(
ParserCreateSettingsProfileQuery.cpp
ParserCreateUserQuery.cpp
ParserDataType.cpp
ParserDatabaseOrNone.cpp
ParserDescribeTableQuery.cpp
ParserDictionary.cpp
ParserDictionaryAttributeDeclaration.cpp

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@ -1166,6 +1166,23 @@ void WindowTransform::appendChunk(Chunk & chunk)
// Write out the aggregation results.
writeOutCurrentRow();
if (isCancelled())
{
// Good time to check if the query is cancelled. Checking once
// per block might not be enough in severe quadratic cases.
// Just leave the work halfway through and return, the 'prepare'
// method will figure out what to do. Note that this doesn't
// handle 'max_execution_time' and other limits, because these
// limits are only updated between blocks. Eventually we should
// start updating them in background and canceling the processor,
// like we do for Ctrl+C handling.
//
// This class is final, so the check should hopefully be
// devirtualized and become a single never-taken branch that is
// basically free.
return;
}
// Move to the next row. The frame will have to be recalculated.
// The peer group start is updated at the beginning of the loop,
// because current_row might now be past-the-end.
@ -1255,10 +1272,12 @@ IProcessor::Status WindowTransform::prepare()
// next_output_block_number, first_not_ready_row, first_block_number,
// blocks.size());
if (output.isFinished())
if (output.isFinished() || isCancelled())
{
// The consumer asked us not to continue (or we decided it ourselves),
// so we abort.
// so we abort. Not sure what the difference between the two conditions
// is, but it seemed that output.isFinished() is not enough to cancel on
// Ctrl+C. Test manually if you change it.
input.close();
return Status::Finished;
}

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@ -80,8 +80,10 @@ struct RowNumber
* the order of input data. This property also trivially holds for the ROWS and
* GROUPS frames. For the RANGE frame, the proof requires the additional fact
* that the ranges are specified in terms of (the single) ORDER BY column.
*
* `final` is so that the isCancelled() is devirtualized, we call it every row.
*/
class WindowTransform : public IProcessor /* public ISimpleTransform */
class WindowTransform final : public IProcessor
{
public:
WindowTransform(

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@ -31,11 +31,6 @@ SRCS(
Formats/IOutputFormat.cpp
Formats/IRowInputFormat.cpp
Formats/IRowOutputFormat.cpp
Formats/Impl/ArrowBlockInputFormat.cpp
Formats/Impl/ArrowBlockOutputFormat.cpp
Formats/Impl/ArrowBufferedStreams.cpp
Formats/Impl/ArrowColumnToCHColumn.cpp
Formats/Impl/CHColumnToArrowColumn.cpp
Formats/Impl/BinaryRowInputFormat.cpp
Formats/Impl/BinaryRowOutputFormat.cpp
Formats/Impl/CSVRowInputFormat.cpp

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@ -141,6 +141,7 @@ SRCS(
StorageMerge.cpp
StorageMergeTree.cpp
StorageMongoDB.cpp
StorageMongoDBSocketFactory.cpp
StorageMySQL.cpp
StorageNull.cpp
StorageReplicatedMergeTree.cpp

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@ -647,7 +647,7 @@ def run_tests_array(all_tests_with_params):
failures_chain += 1
status += MSG_FAIL
status += print_test_time(total_time)
status += " - having exception:\n{}\n".format(
status += " - having exception in stdout:\n{}\n".format(
'\n'.join(stdout.split('\n')[:100]))
status += 'Database: ' + testcase_args.testcase_database
elif reference_file is None:

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@ -91,6 +91,14 @@ tag4 [0,1,2,3,4,5,6,7,8,9] [5,999,2] [2,888,20] [0,1,3,4,6,7,8,9,20]
[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,100,200,500]
[30,31,32,33,100,200,500]
[100,200,500]
[]
[]
[1,5,7,9]
[5,7,9]
[5,7]
[0,1,2,3,4,5,6,7,8,9]
[30,31,32,33,100,200,500]
[100,200,500]
0
0
0

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@ -286,6 +286,25 @@ select bitmapToArray(bitmapSubsetLimit(bitmapBuild([
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,
100,200,500]), toUInt32(100), toUInt16(200)));
-- subBitmap:
---- Empty
SELECT bitmapToArray(subBitmap(bitmapBuild(emptyArrayUInt32()), toUInt8(0), toUInt32(10)));
SELECT bitmapToArray(subBitmap(bitmapBuild(emptyArrayUInt16()), toUInt32(0), toUInt64(10)));
---- Small
select bitmapToArray(subBitmap(bitmapBuild([1,5,7,9]), toUInt8(0), toUInt32(4)));
select bitmapToArray(subBitmap(bitmapBuild([1,5,7,9]), toUInt32(1), toUInt64(4)));
select bitmapToArray(subBitmap(bitmapBuild([1,5,7,9]), toUInt16(1), toUInt32(2)));
---- Large
select bitmapToArray(subBitmap(bitmapBuild([
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,
100,200,500]), toUInt32(0), toUInt32(10)));
select bitmapToArray(subBitmap(bitmapBuild([
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,
100,200,500]), toUInt32(30), toUInt32(200)));
select bitmapToArray(subBitmap(bitmapBuild([
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,
100,200,500]), toUInt32(34), toUInt16(3)));
-- bitmapMin:
---- Empty
SELECT bitmapMin(bitmapBuild(emptyArrayUInt8()));

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@ -0,0 +1,3 @@
Started
Sent kill request
Exit 138

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@ -0,0 +1,36 @@
#!/usr/bin/env bash
CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
# shellcheck source=../shell_config.sh
. "$CURDIR"/../shell_config.sh
set -e -o pipefail
# Run a test query that takes very long to run.
query_id="01572_kill_window_function-$CLICKHOUSE_DATABASE"
$CLICKHOUSE_CLIENT --query_id="$query_id" --query "SELECT count(1048575) OVER (PARTITION BY intDiv(NULL, number) ORDER BY number DESC NULLS FIRST ROWS BETWEEN CURRENT ROW AND 1048575 FOLLOWING) FROM numbers(255, 1048575)" >/dev/null 2>&1 &
client_pid=$!
echo Started
# Use one query to both kill the test query and verify that it has started,
# because if we try to kill it before it starts, the test will fail.
while [ -z "$($CLICKHOUSE_CLIENT --query "kill query where query_id = '$query_id' and current_database = currentDatabase()")" ]
do
# If we don't yet see the query in the process list, the client should still
# be running. The query is very long.
kill -0 -- $client_pid
sleep 1
done
echo Sent kill request
# Wait for the client to terminate.
client_exit_code=0
wait $client_pid || client_exit_code=$?
echo "Exit $client_exit_code"
# We have tested for Ctrl+C.
# The following client flags don't cancel, but should: --max_execution_time,
# --receive_timeout. Probably needs asynchonous calculation of query limits, as
# discussed with Nikolay on TG: https://t.me/c/1214350934/21492

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@ -0,0 +1,40 @@
#!/usr/bin/expect -f
# This is a test for system.warnings. Testing in interactive mode is necessary,
# as we want to see certain warnings from client
log_user 0
set timeout 60
match_max 100000
# A default timeout action is to do nothing, change it to fail
expect_after {
timeout {
exit 1
}
}
set basedir [file dirname $argv0]
spawn bash -c "source $basedir/../shell_config.sh ; \$CLICKHOUSE_CLIENT_BINARY \$CLICKHOUSE_CLIENT_OPT --disable_suggestion --max_memory_usage_in_client=1"
expect ":) "
send -- "SELECT arrayMap(x -> range(x), range(number)) FROM numbers(1000)\r"
expect "Code: 241"
expect ":) "
# Exit.
send -- "\4"
expect eof
set basedir [file dirname $argv0]
spawn bash -c "source $basedir/../shell_config.sh ; \$CLICKHOUSE_CLIENT_BINARY \$CLICKHOUSE_CLIENT_OPT --disable_suggestion --max_memory_usage_in_client=1"
expect ":) "
send -- "SELECT * FROM (SELECT * FROM system.numbers LIMIT 600000) as num WHERE num.number=60000\r"
expect "60000"
expect ":) "
# Exit.
send -- "\4"
expect eof

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@ -2,19 +2,9 @@
<div class="container text-center">
<h2 id="success-stories" class="display-4">Success stories</h2>
<div class="row">
<div class="col-lg-4 py-3">
<a href="https://blog.cloudflare.com/http-analytics-for-6m-requests-per-second-using-clickhouse/" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<div class="card py-3 dots-lb">
<div class="card-body">
<h4 class="card-title">HTTP and DNS analytics</h4>
<p class="card-text text-muted">by Cloudflare</p>
</div>
</div>
</a>
</div>
<div class="col-lg-4 py-3">
<a href="docs/en/introduction/history/" class="text-reset text-decoration-none">
<div class="card py-3 dots-cc">
<div class="card py-3 dots-lb">
<div class="card-body">
<h4 class="card-title">Yandex Metrica</h4>
<p class="card-text text-muted">The original usecase</p>
@ -23,11 +13,21 @@
</a>
</div>
<div class="col-lg-4 py-3">
<a href="https://www.slideshare.net/glebus/using-clickhouse-for-experimentation-104247173" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<a href="https://eng.uber.com/logging/" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<div class="card py-3 dots-cc">
<div class="card-body">
<h4 class="card-title">Log Platform</h4>
<p class="card-text text-muted">at Uber</p>
</div>
</div>
</a>
</div>
<div class="col-lg-4 py-3">
<a href="https://tech.ebayinc.com/engineering/ou-online-analytical-processing/" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<div class="card py-3 dots-rb">
<div class="card-body">
<h4 class="card-title">Experimentation</h4>
<p class="card-text text-muted">at Spotify</p>
<h4 class="card-title">Analytical Processing</h4>
<p class="card-text text-muted">at eBay</p>
</div>
</div>
</a>
@ -35,31 +35,31 @@
</div>
<div class="row">
<div class="col-lg-4 py-3">
<a href="https://translate.yandex.com/translate?url=http%3A%2F%2Fwww.jianshu.com%2Fp%2F4c86a2478cca&amp;lang=zh-en" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<a href="https://blog.cloudflare.com/http-analytics-for-6m-requests-per-second-using-clickhouse/" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<div class="card py-3 dots-rb">
<div class="card-body">
<h4 class="card-title">OLAP contest victory</h4>
<p class="card-text text-muted">by Analysys</p>
<h4 class="card-title">HTTP and DNS analytics</h4>
<p class="card-text text-muted">at Cloudflare</p>
</div>
</div>
</a>
</div>
<div class="col-lg-4 py-3">
<a href="https://translate.yandex.com/translate?url=http%3A%2F%2Fsouslecapot.net%2F2018%2F11%2F21%2Fpatrick-chatain-vp-engineering-chez-contentsquare-penser-davantage-amelioration-continue-que-revolution-constante%2F&lang=fr-en" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<a href="https://www.slideshare.net/glebus/using-clickhouse-for-experimentation-104247173" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
<div class="card py-3 dots-rhb">
<div class="card-body">
<h4 class="card-title">Digital experience analytics</h4>
<p class="card-text text-muted">by ContentSquare</p>
<h4 class="card-title">Experimentation</h4>
<p class="card-text text-muted">at Spotify</p>
</div>
</div>
</a>
</div>
<div class="col-lg-4 py-3">
<a href="https://translate.yandex.com/translate?url=https%3A%2F%2Ftech.geniee.co.jp%2Fentry%2F2017%2F07%2F20%2F160100" class="text-reset text-decoration-none" rel="external nofollow noreferrer" target="_blank">
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<h4 class="card-title">Speeding up Report API</h4>
<p class="card-text text-muted">at Geniee</p>
<h4 class="card-title">Business Intelligence</h4>
<p class="card-text text-muted">at Deutsche Bank</p>
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