ClickHouse/dbms/src/Storages/System/StorageSystemZooKeeper.cpp

154 lines
5.4 KiB
C++
Raw Normal View History

#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeDateTime.h>
#include <Storages/System/StorageSystemZooKeeper.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTFunction.h>
#include <Interpreters/Context.h>
#include <Common/ZooKeeper/ZooKeeper.h>
2017-07-13 20:58:19 +00:00
#include <Common/typeid_cast.h>
namespace DB
{
2018-07-24 18:40:53 +00:00
NamesAndTypesList StorageSystemZooKeeper::getNamesAndTypes()
{
return {
{ "name", std::make_shared<DataTypeString>() },
{ "value", std::make_shared<DataTypeString>() },
{ "czxid", std::make_shared<DataTypeInt64>() },
{ "mzxid", std::make_shared<DataTypeInt64>() },
{ "ctime", std::make_shared<DataTypeDateTime>() },
{ "mtime", std::make_shared<DataTypeDateTime>() },
{ "version", std::make_shared<DataTypeInt32>() },
{ "cversion", std::make_shared<DataTypeInt32>() },
{ "aversion", std::make_shared<DataTypeInt32>() },
{ "ephemeralOwner", std::make_shared<DataTypeInt64>() },
{ "dataLength", std::make_shared<DataTypeInt32>() },
{ "numChildren", std::make_shared<DataTypeInt32>() },
{ "pzxid", std::make_shared<DataTypeInt64>() },
{ "path", std::make_shared<DataTypeString>() },
};
}
static bool extractPathImpl(const IAST & elem, String & res)
{
const ASTFunction * function = typeid_cast<const ASTFunction *>(&elem);
if (!function)
return false;
if (function->name == "and")
{
for (size_t i = 0; i < function->arguments->children.size(); ++i)
if (extractPathImpl(*function->arguments->children[i], res))
return true;
return false;
}
if (function->name == "equals")
{
const ASTExpressionList & args = typeid_cast<const ASTExpressionList &>(*function->arguments);
const IAST * value;
if (args.children.size() != 2)
return false;
const ASTIdentifier * ident;
if ((ident = typeid_cast<const ASTIdentifier *>(&*args.children.at(0))))
value = &*args.children.at(1);
else if ((ident = typeid_cast<const ASTIdentifier *>(&*args.children.at(1))))
value = &*args.children.at(0);
else
return false;
if (ident->name != "path")
return false;
const ASTLiteral * literal = typeid_cast<const ASTLiteral *>(value);
if (!literal)
return false;
if (literal->value.getType() != Field::Types::String)
return false;
res = literal->value.safeGet<String>();
return true;
}
return false;
}
2017-03-12 19:18:07 +00:00
/** Retrieve from the query a condition of the form `path = 'path'`, from conjunctions in the WHERE clause.
*/
static String extractPath(const ASTPtr & query)
{
const ASTSelectQuery & select = typeid_cast<const ASTSelectQuery &>(*query);
if (!select.where_expression)
return "";
String res;
return extractPathImpl(*select.where_expression, res) ? res : "";
}
void StorageSystemZooKeeper::fillData(MutableColumns & res_columns, const Context & context, const SelectQueryInfo & query_info) const
{
String path = extractPath(query_info.query);
if (path.empty())
throw Exception("SELECT from system.zookeeper table must contain condition like path = 'path' in WHERE clause.");
zkutil::ZooKeeperPtr zookeeper = context.getZooKeeper();
/// In all cases except the root, path must not end with a slash.
String path_corrected = path;
if (path_corrected != "/" && path_corrected.back() == '/')
path_corrected.resize(path_corrected.size() - 1);
zkutil::Strings nodes = zookeeper->getChildren(path_corrected);
String path_part = path_corrected;
if (path_part == "/")
path_part.clear();
std::vector<std::future<Coordination::GetResponse>> futures;
futures.reserve(nodes.size());
for (const String & node : nodes)
futures.push_back(zookeeper->asyncTryGet(path_part + '/' + node));
for (size_t i = 0, size = nodes.size(); i < size; ++i)
{
auto res = futures[i].get();
if (res.error == Coordination::ZNONODE)
continue; /// Node was deleted meanwhile.
const Coordination::Stat & stat = res.stat;
size_t col_num = 0;
res_columns[col_num++]->insert(nodes[i]);
res_columns[col_num++]->insert(res.data);
res_columns[col_num++]->insert(Int64(stat.czxid));
res_columns[col_num++]->insert(Int64(stat.mzxid));
res_columns[col_num++]->insert(UInt64(stat.ctime / 1000));
res_columns[col_num++]->insert(UInt64(stat.mtime / 1000));
res_columns[col_num++]->insert(Int64(stat.version));
res_columns[col_num++]->insert(Int64(stat.cversion));
res_columns[col_num++]->insert(Int64(stat.aversion));
res_columns[col_num++]->insert(Int64(stat.ephemeralOwner));
res_columns[col_num++]->insert(Int64(stat.dataLength));
res_columns[col_num++]->insert(Int64(stat.numChildren));
res_columns[col_num++]->insert(Int64(stat.pzxid));
res_columns[col_num++]->insert(path); /// This is the original path. In order to process the request, condition in WHERE should be triggered.
}
}
}