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support clickhouse as mysql federated server

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This commit is contained in:
Maksim Fedotov 2019-11-11 17:31:12 +03:00
parent c71e874a8c
commit 0403444f14
1 changed files with 48 additions and 20 deletions
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68
dbms/programs/server/MySQLHandler.cpp
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@ -15,6 +15,7 @@
#include <IO/ReadBufferFromString.h>
#include <IO/WriteBufferFromPocoSocket.h>
#include <Storages/IStorage.h>
#include <boost/algorithm/string/replace.hpp>
#if USE_POCO_NETSSL
#include <Poco/Net/SecureStreamSocket.h>
@ -266,29 +267,56 @@ void MySQLHandler::comPing()
packet_sender->sendPacket(OK_Packet(0x0, client_capability_flags, 0, 0, 0), true);
}
void MySQLHandler::comQuery(ReadBuffer & payload)
{
bool with_output = false;
std::function<void(const String &)> set_content_type = [&with_output](const String &) -> void {
with_output = true;
};
void MySQLHandler::comQuery(ReadBuffer &payload) {
std::string query = std::string(payload.position(), payload.buffer().end());
const String query("select ''");
ReadBufferFromString empty_select(query);
bool should_replace = false;
// Translate query from MySQL to ClickHouse.
// This is a temporary workaround until ClickHouse supports the syntax "@@var_name".
if (std::string(payload.position(), payload.buffer().end()) == "select @@version_comment limit 1") // MariaDB client starts session with that query
// This is a workaround in order to support adding ClickHouse to MySQL using federated server.
// As Clickhouse doesn't support these statements, we just send OK packet in response.
if (
(0 == strncasecmp("SET NAMES", query.c_str(), 9))
||
(0 == strncasecmp("SET character_set_results", query.c_str(), 25))
||
(0 == strncasecmp("SET FOREIGN_KEY_CHECKS", query.c_str(), 22))
||
(0 == strncasecmp("SET AUTOCOMMIT", query.c_str(), 14))
||
(0 == strncasecmp("SET SESSION TRANSACTION ISOLATION LEVEL", query.c_str(), 39))
)
{
should_replace = true;
}
Context query_context = connection_context;
executeQuery(should_replace ? empty_select : payload, *out, true, query_context, set_content_type, nullptr);
if (!with_output)
packet_sender->sendPacket(OK_Packet(0x00, client_capability_flags, 0, 0, 0), true);
}
else
{
bool with_output = false;
std::function<void(const String &)> set_content_type = [&with_output](const String &) -> void {
with_output = true;
};
String replacement_query = ("select ''");
bool should_replace = false;
// Translate query from MySQL to ClickHouse.
// This is a temporary workaround until ClickHouse supports the syntax "@@var_name".
if (query == "select @@version_comment limit 1") // MariaDB client starts session with that query
{
should_replace = true;
}
// This is a workaround in order to support adding ClickHouse to MySQL using federated server.
if (0 == strncasecmp("SHOW TABLE STATUS LIKE", query.c_str(), 22))
{
should_replace = true;
replacement_query = boost::replace_all_copy(query, "SHOW TABLE STATUS LIKE ", "SELECT name AS Name, engine AS Engine, '10' AS Version, 'Dynamic' AS Row_format, 0 AS Rows, 0 AS Avg_row_length, 0 AS Data_length, 0 AS Max_data_length, 0 AS Index_length, 0 AS Data_free, 'NULL' AS Auto_increment, metadata_modification_time AS Create_time, metadata_modification_time AS Update_time, metadata_modification_time AS Check_time, 'utf8_bin' AS Collation, 'NULL' AS Checksum, '' AS Create_options, '' AS Comment FROM system.tables WHERE name=");
}
ReadBufferFromString replacement(replacement_query);
Context query_context = connection_context;
executeQuery(should_replace ? replacement : payload, *out, true, query_context, set_content_type, nullptr);
if (!with_output)
packet_sender->sendPacket(OK_Packet(0x00, client_capability_flags, 0, 0, 0), true);
}
}
void MySQLHandler::authPluginSSL()