servers/mysql/
federated.rs

1// Copyright 2023 Greptime Team
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Use regex to filter out some MySQL federated components' emitted statements.
16//! Inspired by Databend's "[mysql_federated.rs](https://github.com/datafuselabs/databend/blob/ac706bf65845e6895141c96c0a10bad6fdc2d367/src/query/service/src/servers/mysql/mysql_federated.rs)".
17
18use std::collections::HashMap;
19use std::sync::Arc;
20
21use common_query::Output;
22use common_recordbatch::RecordBatches;
23use common_time::timezone::system_timezone_name;
24use datatypes::prelude::ConcreteDataType;
25use datatypes::schema::{ColumnSchema, Schema};
26use datatypes::vectors::StringVector;
27use once_cell::sync::Lazy;
28use regex::bytes::RegexSet;
29use regex::Regex;
30use session::context::QueryContextRef;
31use session::SessionRef;
32
33static SELECT_VAR_PATTERN: Lazy<Regex> = Lazy::new(|| Regex::new("(?i)^(SELECT @@(.*))").unwrap());
34static MYSQL_CONN_JAVA_PATTERN: Lazy<Regex> =
35    Lazy::new(|| Regex::new("(?i)^(/\\* mysql-connector-j(.*))").unwrap());
36static SHOW_LOWER_CASE_PATTERN: Lazy<Regex> =
37    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES LIKE 'lower_case_table_names'(.*))").unwrap());
38static SHOW_VARIABLES_LIKE_PATTERN: Lazy<Regex> =
39    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES( LIKE (.*))?)").unwrap());
40
41// SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP());
42static SELECT_TIME_DIFF_FUNC_PATTERN: Lazy<Regex> =
43    Lazy::new(|| Regex::new("(?i)^(SELECT TIMEDIFF\\(NOW\\(\\), UTC_TIMESTAMP\\(\\)\\))").unwrap());
44
45// sqlalchemy < 1.4.30
46static SHOW_SQL_MODE_PATTERN: Lazy<Regex> =
47    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES LIKE 'sql_mode'(.*))").unwrap());
48
49static OTHER_NOT_SUPPORTED_STMT: Lazy<RegexSet> = Lazy::new(|| {
50    RegexSet::new([
51        // Txn.
52        "(?i)^(ROLLBACK(.*))",
53        "(?i)^(COMMIT(.*))",
54        "(?i)^(START(.*))",
55
56        // Set.
57        "(?i)^(SET NAMES(.*))",
58        "(?i)^(SET character_set_results(.*))",
59        "(?i)^(SET net_write_timeout(.*))",
60        "(?i)^(SET FOREIGN_KEY_CHECKS(.*))",
61        "(?i)^(SET AUTOCOMMIT(.*))",
62        "(?i)^(SET SQL_LOG_BIN(.*))",
63        "(?i)^(SET SESSION TRANSACTION(.*))",
64        "(?i)^(SET TRANSACTION(.*))",
65        "(?i)^(SET sql_mode(.*))",
66        "(?i)^(SET SQL_SELECT_LIMIT(.*))",
67        "(?i)^(SET PROFILING(.*))",
68
69        // mysqlclient.
70        "(?i)^(SELECT \\$\\$)",
71
72        // mysqldump.
73        "(?i)^(SET SQL_QUOTE_SHOW_CREATE(.*))",
74        "(?i)^(LOCK TABLES(.*))",
75        "(?i)^(UNLOCK TABLES(.*))",
76        "(?i)^(SELECT LOGFILE_GROUP_NAME, FILE_NAME, TOTAL_EXTENTS, INITIAL_SIZE, ENGINE, EXTRA FROM INFORMATION_SCHEMA.FILES(.*))",
77
78        // mydumper.
79        "(?i)^(/\\*!80003 SET(.*) \\*/)$",
80        "(?i)^(SHOW MASTER STATUS)",
81        "(?i)^(SHOW ALL SLAVES STATUS)",
82        "(?i)^(LOCK BINLOG FOR BACKUP)",
83        "(?i)^(LOCK TABLES FOR BACKUP)",
84        "(?i)^(UNLOCK BINLOG(.*))",
85        "(?i)^(/\\*!40101 SET(.*) \\*/)$",
86
87        // DBeaver.
88        "(?i)^(SHOW WARNINGS)",
89        "(?i)^(/\\* ApplicationName=(.*)SHOW WARNINGS)",
90        "(?i)^(/\\* ApplicationName=(.*)SHOW PLUGINS)",
91        "(?i)^(/\\* ApplicationName=(.*)SHOW ENGINES)",
92        "(?i)^(/\\* ApplicationName=(.*)SELECT @@(.*))",
93        "(?i)^(/\\* ApplicationName=(.*)SHOW @@(.*))",
94        "(?i)^(/\\* ApplicationName=(.*)SET net_write_timeout(.*))",
95        "(?i)^(/\\* ApplicationName=(.*)SET SQL_SELECT_LIMIT(.*))",
96        "(?i)^(/\\* ApplicationName=(.*)SHOW VARIABLES(.*))",
97
98        // pt-toolkit
99        "(?i)^(/\\*!40101 SET(.*) \\*/)$",
100
101        // mysqldump 5.7.16
102        "(?i)^(/\\*!40100 SET(.*) \\*/)$",
103        "(?i)^(/\\*!40103 SET(.*) \\*/)$",
104        "(?i)^(/\\*!40111 SET(.*) \\*/)$",
105        "(?i)^(/\\*!40101 SET(.*) \\*/)$",
106        "(?i)^(/\\*!40014 SET(.*) \\*/)$",
107        "(?i)^(/\\*!40000 SET(.*) \\*/)$",
108    ]).unwrap()
109});
110
111static VAR_VALUES: Lazy<HashMap<&str, &str>> = Lazy::new(|| {
112    HashMap::from([
113        ("tx_isolation", "REPEATABLE-READ"),
114        ("session.tx_isolation", "REPEATABLE-READ"),
115        ("transaction_isolation", "REPEATABLE-READ"),
116        ("session.transaction_isolation", "REPEATABLE-READ"),
117        ("session.transaction_read_only", "0"),
118        ("max_allowed_packet", "134217728"),
119        ("interactive_timeout", "31536000"),
120        ("wait_timeout", "31536000"),
121        ("net_write_timeout", "31536000"),
122        ("version_comment", "Greptime"),
123    ])
124});
125
126// Recordbatches for select function.
127// Format:
128// |function_name|
129// |value|
130fn select_function(name: &str, value: &str) -> RecordBatches {
131    let schema = Arc::new(Schema::new(vec![ColumnSchema::new(
132        name,
133        ConcreteDataType::string_datatype(),
134        true,
135    )]));
136    let columns = vec![Arc::new(StringVector::from(vec![value])) as _];
137    RecordBatches::try_from_columns(schema, columns)
138        // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
139        .unwrap()
140}
141
142// Recordbatches for show variable statement.
143// Format is:
144// | Variable_name | Value |
145// | xx            | yy    |
146fn show_variables(name: &str, value: &str) -> RecordBatches {
147    let schema = Arc::new(Schema::new(vec![
148        ColumnSchema::new("Variable_name", ConcreteDataType::string_datatype(), true),
149        ColumnSchema::new("Value", ConcreteDataType::string_datatype(), true),
150    ]));
151    let columns = vec![
152        Arc::new(StringVector::from(vec![name])) as _,
153        Arc::new(StringVector::from(vec![value])) as _,
154    ];
155    RecordBatches::try_from_columns(schema, columns)
156        // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
157        .unwrap()
158}
159
160fn select_variable(query: &str, query_context: QueryContextRef) -> Option<Output> {
161    let mut fields = vec![];
162    let mut values = vec![];
163
164    // query like "SELECT @@aa, @@bb as cc, @dd..."
165    let query = query.to_lowercase();
166    let vars: Vec<&str> = query.split("@@").collect();
167    if vars.len() <= 1 {
168        return None;
169    }
170
171    // skip the first "select"
172    for var in vars.iter().skip(1) {
173        let var = var.trim_matches(|c| c == ' ' || c == ',');
174        let var_as: Vec<&str> = var
175            .split(" as ")
176            .map(|x| {
177                x.trim_matches(|c| c == ' ')
178                    .split_whitespace()
179                    .next()
180                    .unwrap_or("")
181            })
182            .collect();
183
184        // get value of variables from known sources or fallback to defaults
185        let value = match var_as[0] {
186            "session.time_zone" | "time_zone" => query_context.timezone().to_string(),
187            "system_time_zone" => system_timezone_name(),
188            _ => VAR_VALUES
189                .get(var_as[0])
190                .map(|v| v.to_string())
191                .unwrap_or_else(|| "0".to_owned()),
192        };
193
194        values.push(Arc::new(StringVector::from(vec![value])) as _);
195        match var_as.len() {
196            1 => {
197                // @@aa
198                // field is '@@aa'
199                fields.push(ColumnSchema::new(
200                    format!("@@{}", var_as[0]),
201                    ConcreteDataType::string_datatype(),
202                    true,
203                ));
204            }
205            2 => {
206                // @@bb as cc:
207                // var is 'bb'.
208                // field is 'cc'.
209                fields.push(ColumnSchema::new(
210                    var_as[1],
211                    ConcreteDataType::string_datatype(),
212                    true,
213                ));
214            }
215            _ => return None,
216        }
217    }
218
219    let schema = Arc::new(Schema::new(fields));
220    // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
221    let batches = RecordBatches::try_from_columns(schema, values).unwrap();
222    Some(Output::new_with_record_batches(batches))
223}
224
225fn check_select_variable(query: &str, query_context: QueryContextRef) -> Option<Output> {
226    if [&SELECT_VAR_PATTERN, &MYSQL_CONN_JAVA_PATTERN]
227        .iter()
228        .any(|r| r.is_match(query))
229    {
230        select_variable(query, query_context)
231    } else {
232        None
233    }
234}
235
236fn check_show_variables(query: &str) -> Option<Output> {
237    let recordbatches = if SHOW_SQL_MODE_PATTERN.is_match(query) {
238        Some(show_variables("sql_mode", "ONLY_FULL_GROUP_BY STRICT_TRANS_TABLES NO_ZERO_IN_DATE NO_ZERO_DATE ERROR_FOR_DIVISION_BY_ZERO NO_ENGINE_SUBSTITUTION"))
239    } else if SHOW_LOWER_CASE_PATTERN.is_match(query) {
240        Some(show_variables("lower_case_table_names", "0"))
241    } else if SHOW_VARIABLES_LIKE_PATTERN.is_match(query) {
242        Some(show_variables("", ""))
243    } else {
244        None
245    };
246    recordbatches.map(Output::new_with_record_batches)
247}
248
249// Check for SET or others query, this is the final check of the federated query.
250fn check_others(query: &str, _query_ctx: QueryContextRef) -> Option<Output> {
251    if OTHER_NOT_SUPPORTED_STMT.is_match(query.as_bytes()) {
252        return Some(Output::new_with_record_batches(RecordBatches::empty()));
253    }
254
255    let recordbatches = if SELECT_TIME_DIFF_FUNC_PATTERN.is_match(query) {
256        Some(select_function(
257            "TIMEDIFF(NOW(), UTC_TIMESTAMP())",
258            "00:00:00",
259        ))
260    } else {
261        None
262    };
263    recordbatches.map(Output::new_with_record_batches)
264}
265
266// Check whether the query is a federated or driver setup command,
267// and return some faked results if there are any.
268pub(crate) fn check(
269    query: &str,
270    query_ctx: QueryContextRef,
271    _session: SessionRef,
272) -> Option<Output> {
273    // INSERT don't need MySQL federated check. We assume the query doesn't contain
274    // federated or driver setup command if it starts with a 'INSERT' statement.
275    let the_6th_index = query.char_indices().nth(6).map(|(i, _)| i);
276    if let Some(index) = the_6th_index {
277        if query[..index].eq_ignore_ascii_case("INSERT") {
278            return None;
279        }
280    }
281
282    // First to check the query is like "select @@variables".
283    check_select_variable(query, query_ctx.clone())
284        // Then to check "show variables like ...".
285        .or_else(|| check_show_variables(query))
286        // Last check
287        .or_else(|| check_others(query, query_ctx))
288}
289
290#[cfg(test)]
291mod test {
292
293    use common_query::OutputData;
294    use common_time::timezone::set_default_timezone;
295    use session::context::{Channel, QueryContext};
296    use session::Session;
297
298    use super::*;
299
300    #[test]
301    fn test_check_abnormal() {
302        let session = Arc::new(Session::new(None, Channel::Mysql, Default::default(), 0));
303        let query = "🫣一点不正常的东西🫣";
304        let output = check(query, QueryContext::arc(), session.clone());
305
306        assert!(output.is_none());
307    }
308
309    #[test]
310    fn test_check() {
311        let session = Arc::new(Session::new(None, Channel::Mysql, Default::default(), 0));
312        let query = "select 1";
313        let result = check(query, QueryContext::arc(), session.clone());
314        assert!(result.is_none());
315
316        let query = "select version";
317        let output = check(query, QueryContext::arc(), session.clone());
318        assert!(output.is_none());
319
320        fn test(query: &str, expected: &str) {
321            let session = Arc::new(Session::new(None, Channel::Mysql, Default::default(), 0));
322            let output = check(query, QueryContext::arc(), session.clone());
323            match output.unwrap().data {
324                OutputData::RecordBatches(r) => {
325                    assert_eq!(&r.pretty_print().unwrap(), expected)
326                }
327                _ => unreachable!(),
328            }
329        }
330
331        let query = "SELECT @@version_comment LIMIT 1";
332        let expected = "\
333+-------------------+
334| @@version_comment |
335+-------------------+
336| Greptime          |
337+-------------------+";
338        test(query, expected);
339
340        // variables
341        let query = "select @@tx_isolation, @@session.tx_isolation";
342        let expected = "\
343+-----------------+------------------------+
344| @@tx_isolation  | @@session.tx_isolation |
345+-----------------+------------------------+
346| REPEATABLE-READ | REPEATABLE-READ        |
347+-----------------+------------------------+";
348        test(query, expected);
349
350        // set system timezone
351        set_default_timezone(Some("Asia/Shanghai")).unwrap();
352        // complex variables
353        let query = "/* mysql-connector-java-8.0.17 (Revision: 16a712ddb3f826a1933ab42b0039f7fb9eebc6ec) */SELECT  @@session.auto_increment_increment AS auto_increment_increment, @@character_set_client AS character_set_client, @@character_set_connection AS character_set_connection, @@character_set_results AS character_set_results, @@character_set_server AS character_set_server, @@collation_server AS collation_server, @@collation_connection AS collation_connection, @@init_connect AS init_connect, @@interactive_timeout AS interactive_timeout, @@license AS license, @@lower_case_table_names AS lower_case_table_names, @@max_allowed_packet AS max_allowed_packet, @@net_write_timeout AS net_write_timeout, @@performance_schema AS performance_schema, @@sql_mode AS sql_mode, @@system_time_zone AS system_time_zone, @@time_zone AS time_zone, @@transaction_isolation AS transaction_isolation, @@wait_timeout AS wait_timeout;";
354        let expected = "\
355+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+
356| auto_increment_increment | character_set_client | character_set_connection | character_set_results | character_set_server | collation_server | collation_connection | init_connect | interactive_timeout | license | lower_case_table_names | max_allowed_packet | net_write_timeout | performance_schema | sql_mode | system_time_zone | time_zone     | transaction_isolation | wait_timeout; |
357+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+
358| 0                        | 0                    | 0                        | 0                     | 0                    | 0                | 0                    | 0            | 31536000            | 0       | 0                      | 134217728          | 31536000          | 0                  | 0        | Asia/Shanghai    | Asia/Shanghai | REPEATABLE-READ       | 31536000      |
359+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+";
360        test(query, expected);
361
362        let query = "show variables";
363        let expected = "\
364+---------------+-------+
365| Variable_name | Value |
366+---------------+-------+
367|               |       |
368+---------------+-------+";
369        test(query, expected);
370
371        let query = "show variables like 'lower_case_table_names'";
372        let expected = "\
373+------------------------+-------+
374| Variable_name          | Value |
375+------------------------+-------+
376| lower_case_table_names | 0     |
377+------------------------+-------+";
378        test(query, expected);
379
380        let query = "SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP())";
381        let expected = "\
382+----------------------------------+
383| TIMEDIFF(NOW(), UTC_TIMESTAMP()) |
384+----------------------------------+
385| 00:00:00                         |
386+----------------------------------+";
387        test(query, expected);
388    }
389}
servers/mysql/federated.rs

servers/mysql/
federated.rs
