1 | #include <Parsers/ASTRenameQuery.h> |
2 | #include <Databases/IDatabase.h> |
3 | #include <Interpreters/Context.h> |
4 | #include <Interpreters/InterpreterRenameQuery.h> |
5 | #include <Storages/IStorage.h> |
6 | #include <Interpreters/DDLWorker.h> |
7 | #include <Common/typeid_cast.h> |
8 | |
9 | |
10 | namespace DB |
11 | { |
12 | |
13 | |
14 | InterpreterRenameQuery::InterpreterRenameQuery(const ASTPtr & query_ptr_, Context & context_) |
15 | : query_ptr(query_ptr_), context(context_) |
16 | { |
17 | } |
18 | |
19 | |
20 | struct RenameDescription |
21 | { |
22 | RenameDescription(const ASTRenameQuery::Element & elem, const String & current_database) : |
23 | from_database_name(elem.from.database.empty() ? current_database : elem.from.database), |
24 | from_table_name(elem.from.table), |
25 | to_database_name(elem.to.database.empty() ? current_database : elem.to.database), |
26 | to_table_name(elem.to.table) |
27 | {} |
28 | |
29 | String from_database_name; |
30 | String from_table_name; |
31 | |
32 | String to_database_name; |
33 | String to_table_name; |
34 | }; |
35 | |
36 | |
37 | BlockIO InterpreterRenameQuery::execute() |
38 | { |
39 | const auto & rename = query_ptr->as<ASTRenameQuery &>(); |
40 | |
41 | if (!rename.cluster.empty()) |
42 | { |
43 | NameSet databases; |
44 | for (const auto & elem : rename.elements) |
45 | { |
46 | databases.emplace(elem.from.database); |
47 | databases.emplace(elem.to.database); |
48 | } |
49 | |
50 | return executeDDLQueryOnCluster(query_ptr, context, std::move(databases)); |
51 | } |
52 | |
53 | String path = context.getPath(); |
54 | String current_database = context.getCurrentDatabase(); |
55 | |
56 | /** In case of error while renaming, it is possible that only part of tables was renamed |
57 | * or we will be in inconsistent state. (It is worth to be fixed.) |
58 | */ |
59 | |
60 | std::vector<RenameDescription> descriptions; |
61 | descriptions.reserve(rename.elements.size()); |
62 | |
63 | /// To avoid deadlocks, we must acquire locks for tables in same order in any different RENAMES. |
64 | struct UniqueTableName |
65 | { |
66 | String database_name; |
67 | String table_name; |
68 | |
69 | UniqueTableName(const String & database_name_, const String & table_name_) |
70 | : database_name(database_name_), table_name(table_name_) {} |
71 | |
72 | bool operator< (const UniqueTableName & rhs) const |
73 | { |
74 | return std::tie(database_name, table_name) < std::tie(rhs.database_name, rhs.table_name); |
75 | } |
76 | }; |
77 | |
78 | /// Don't allow to drop tables (that we are renaming); don't allow to create tables in places where tables will be renamed. |
79 | std::map<UniqueTableName, std::unique_ptr<DDLGuard>> table_guards; |
80 | |
81 | for (const auto & elem : rename.elements) |
82 | { |
83 | descriptions.emplace_back(elem, current_database); |
84 | |
85 | UniqueTableName from(descriptions.back().from_database_name, descriptions.back().from_table_name); |
86 | UniqueTableName to(descriptions.back().to_database_name, descriptions.back().to_table_name); |
87 | |
88 | table_guards[from]; |
89 | table_guards[to]; |
90 | } |
91 | |
92 | /// Must do it in consistent order. |
93 | for (auto & table_guard : table_guards) |
94 | table_guard.second = context.getDDLGuard(table_guard.first.database_name, table_guard.first.table_name); |
95 | |
96 | for (auto & elem : descriptions) |
97 | { |
98 | context.assertTableDoesntExist(elem.to_database_name, elem.to_table_name); |
99 | auto from_table = context.getTable(elem.from_database_name, elem.from_table_name); |
100 | auto from_table_lock = from_table->lockExclusively(context.getCurrentQueryId()); |
101 | |
102 | context.getDatabase(elem.from_database_name)->renameTable( |
103 | context, |
104 | elem.from_table_name, |
105 | *context.getDatabase(elem.to_database_name), |
106 | elem.to_table_name, |
107 | from_table_lock); |
108 | } |
109 | |
110 | return {}; |
111 | } |
112 | |
113 | |
114 | } |
115 | |