servers/mysql/
federated.rs

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
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
// Copyright 2023 Greptime Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Use regex to filter out some MySQL federated components' emitted statements.
//! Inspired by Databend's "[mysql_federated.rs](https://github.com/datafuselabs/databend/blob/ac706bf65845e6895141c96c0a10bad6fdc2d367/src/query/service/src/servers/mysql/mysql_federated.rs)".

use std::collections::HashMap;
use std::sync::Arc;

use common_query::Output;
use common_recordbatch::RecordBatches;
use common_time::timezone::system_timezone_name;
use datatypes::prelude::ConcreteDataType;
use datatypes::schema::{ColumnSchema, Schema};
use datatypes::vectors::StringVector;
use once_cell::sync::Lazy;
use regex::bytes::RegexSet;
use regex::Regex;
use session::context::QueryContextRef;
use session::SessionRef;

static SELECT_VAR_PATTERN: Lazy<Regex> = Lazy::new(|| Regex::new("(?i)^(SELECT @@(.*))").unwrap());
static MYSQL_CONN_JAVA_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new("(?i)^(/\\* mysql-connector-j(.*))").unwrap());
static SHOW_LOWER_CASE_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES LIKE 'lower_case_table_names'(.*))").unwrap());
static SHOW_VARIABLES_LIKE_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES( LIKE (.*))?)").unwrap());

// SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP());
static SELECT_TIME_DIFF_FUNC_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new("(?i)^(SELECT TIMEDIFF\\(NOW\\(\\), UTC_TIMESTAMP\\(\\)\\))").unwrap());

// sqlalchemy < 1.4.30
static SHOW_SQL_MODE_PATTERN: Lazy<Regex> =
    Lazy::new(|| Regex::new("(?i)^(SHOW VARIABLES LIKE 'sql_mode'(.*))").unwrap());

static OTHER_NOT_SUPPORTED_STMT: Lazy<RegexSet> = Lazy::new(|| {
    RegexSet::new([
        // Txn.
        "(?i)^(ROLLBACK(.*))",
        "(?i)^(COMMIT(.*))",
        "(?i)^(START(.*))",

        // Set.
        "(?i)^(SET NAMES(.*))",
        "(?i)^(SET character_set_results(.*))",
        "(?i)^(SET net_write_timeout(.*))",
        "(?i)^(SET FOREIGN_KEY_CHECKS(.*))",
        "(?i)^(SET AUTOCOMMIT(.*))",
        "(?i)^(SET SQL_LOG_BIN(.*))",
        "(?i)^(SET SESSION TRANSACTION(.*))",
        "(?i)^(SET TRANSACTION(.*))",
        "(?i)^(SET sql_mode(.*))",
        "(?i)^(SET SQL_SELECT_LIMIT(.*))",
        "(?i)^(SET @@(.*))",
        "(?i)^(SET PROFILING(.*))",

        // mysqlclient.
        "(?i)^(SELECT \\$\\$)",

        // mysqldump.
        "(?i)^(SET SQL_QUOTE_SHOW_CREATE(.*))",
        "(?i)^(LOCK TABLES(.*))",
        "(?i)^(UNLOCK TABLES(.*))",
        "(?i)^(SELECT LOGFILE_GROUP_NAME, FILE_NAME, TOTAL_EXTENTS, INITIAL_SIZE, ENGINE, EXTRA FROM INFORMATION_SCHEMA.FILES(.*))",

        // mydumper.
        "(?i)^(/\\*!80003 SET(.*) \\*/)$",
        "(?i)^(SHOW MASTER STATUS)",
        "(?i)^(SHOW ALL SLAVES STATUS)",
        "(?i)^(LOCK BINLOG FOR BACKUP)",
        "(?i)^(LOCK TABLES FOR BACKUP)",
        "(?i)^(UNLOCK BINLOG(.*))",
        "(?i)^(/\\*!40101 SET(.*) \\*/)$",

        // DBeaver.
        "(?i)^(SHOW WARNINGS)",
        "(?i)^(/\\* ApplicationName=(.*)SHOW WARNINGS)",
        "(?i)^(/\\* ApplicationName=(.*)SHOW PLUGINS)",
        "(?i)^(/\\* ApplicationName=(.*)SHOW ENGINES)",
        "(?i)^(/\\* ApplicationName=(.*)SELECT @@(.*))",
        "(?i)^(/\\* ApplicationName=(.*)SHOW @@(.*))",
        "(?i)^(/\\* ApplicationName=(.*)SET net_write_timeout(.*))",
        "(?i)^(/\\* ApplicationName=(.*)SET SQL_SELECT_LIMIT(.*))",
        "(?i)^(/\\* ApplicationName=(.*)SHOW VARIABLES(.*))",

        // pt-toolkit
        "(?i)^(/\\*!40101 SET(.*) \\*/)$",

        // mysqldump 5.7.16
        "(?i)^(/\\*!40100 SET(.*) \\*/)$",
        "(?i)^(/\\*!40103 SET(.*) \\*/)$",
        "(?i)^(/\\*!40111 SET(.*) \\*/)$",
        "(?i)^(/\\*!40101 SET(.*) \\*/)$",
        "(?i)^(/\\*!40014 SET(.*) \\*/)$",
        "(?i)^(/\\*!40000 SET(.*) \\*/)$",
    ]).unwrap()
});

static VAR_VALUES: Lazy<HashMap<&str, &str>> = Lazy::new(|| {
    HashMap::from([
        ("tx_isolation", "REPEATABLE-READ"),
        ("session.tx_isolation", "REPEATABLE-READ"),
        ("transaction_isolation", "REPEATABLE-READ"),
        ("session.transaction_isolation", "REPEATABLE-READ"),
        ("session.transaction_read_only", "0"),
        ("max_allowed_packet", "134217728"),
        ("interactive_timeout", "31536000"),
        ("wait_timeout", "31536000"),
        ("net_write_timeout", "31536000"),
        ("version_comment", "Greptime"),
    ])
});

// Recordbatches for select function.
// Format:
// |function_name|
// |value|
fn select_function(name: &str, value: &str) -> RecordBatches {
    let schema = Arc::new(Schema::new(vec![ColumnSchema::new(
        name,
        ConcreteDataType::string_datatype(),
        true,
    )]));
    let columns = vec![Arc::new(StringVector::from(vec![value])) as _];
    RecordBatches::try_from_columns(schema, columns)
        // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
        .unwrap()
}

// Recordbatches for show variable statement.
// Format is:
// | Variable_name | Value |
// | xx            | yy    |
fn show_variables(name: &str, value: &str) -> RecordBatches {
    let schema = Arc::new(Schema::new(vec![
        ColumnSchema::new("Variable_name", ConcreteDataType::string_datatype(), true),
        ColumnSchema::new("Value", ConcreteDataType::string_datatype(), true),
    ]));
    let columns = vec![
        Arc::new(StringVector::from(vec![name])) as _,
        Arc::new(StringVector::from(vec![value])) as _,
    ];
    RecordBatches::try_from_columns(schema, columns)
        // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
        .unwrap()
}

fn select_variable(query: &str, query_context: QueryContextRef) -> Option<Output> {
    let mut fields = vec![];
    let mut values = vec![];

    // query like "SELECT @@aa, @@bb as cc, @dd..."
    let query = query.to_lowercase();
    let vars: Vec<&str> = query.split("@@").collect();
    if vars.len() <= 1 {
        return None;
    }

    // skip the first "select"
    for var in vars.iter().skip(1) {
        let var = var.trim_matches(|c| c == ' ' || c == ',');
        let var_as: Vec<&str> = var
            .split(" as ")
            .map(|x| {
                x.trim_matches(|c| c == ' ')
                    .split_whitespace()
                    .next()
                    .unwrap_or("")
            })
            .collect();

        // get value of variables from known sources or fallback to defaults
        let value = match var_as[0] {
            "time_zone" => query_context.timezone().to_string(),
            "system_time_zone" => system_timezone_name(),
            _ => VAR_VALUES
                .get(var_as[0])
                .map(|v| v.to_string())
                .unwrap_or_else(|| "0".to_owned()),
        };

        values.push(Arc::new(StringVector::from(vec![value])) as _);
        match var_as.len() {
            1 => {
                // @@aa
                // field is '@@aa'
                fields.push(ColumnSchema::new(
                    format!("@@{}", var_as[0]),
                    ConcreteDataType::string_datatype(),
                    true,
                ));
            }
            2 => {
                // @@bb as cc:
                // var is 'bb'.
                // field is 'cc'.
                fields.push(ColumnSchema::new(
                    var_as[1],
                    ConcreteDataType::string_datatype(),
                    true,
                ));
            }
            _ => return None,
        }
    }

    let schema = Arc::new(Schema::new(fields));
    // unwrap is safe because the schema and data are definitely able to form a recordbatch, they are all string type
    let batches = RecordBatches::try_from_columns(schema, values).unwrap();
    Some(Output::new_with_record_batches(batches))
}

fn check_select_variable(query: &str, query_context: QueryContextRef) -> Option<Output> {
    if [&SELECT_VAR_PATTERN, &MYSQL_CONN_JAVA_PATTERN]
        .iter()
        .any(|r| r.is_match(query))
    {
        select_variable(query, query_context)
    } else {
        None
    }
}

fn check_show_variables(query: &str) -> Option<Output> {
    let recordbatches = if SHOW_SQL_MODE_PATTERN.is_match(query) {
        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"))
    } else if SHOW_LOWER_CASE_PATTERN.is_match(query) {
        Some(show_variables("lower_case_table_names", "0"))
    } else if SHOW_VARIABLES_LIKE_PATTERN.is_match(query) {
        Some(show_variables("", ""))
    } else {
        None
    };
    recordbatches.map(Output::new_with_record_batches)
}

// Check for SET or others query, this is the final check of the federated query.
fn check_others(query: &str, _query_ctx: QueryContextRef) -> Option<Output> {
    if OTHER_NOT_SUPPORTED_STMT.is_match(query.as_bytes()) {
        return Some(Output::new_with_record_batches(RecordBatches::empty()));
    }

    let recordbatches = if SELECT_TIME_DIFF_FUNC_PATTERN.is_match(query) {
        Some(select_function(
            "TIMEDIFF(NOW(), UTC_TIMESTAMP())",
            "00:00:00",
        ))
    } else {
        None
    };
    recordbatches.map(Output::new_with_record_batches)
}

// Check whether the query is a federated or driver setup command,
// and return some faked results if there are any.
pub(crate) fn check(
    query: &str,
    query_ctx: QueryContextRef,
    _session: SessionRef,
) -> Option<Output> {
    // INSERT don't need MySQL federated check. We assume the query doesn't contain
    // federated or driver setup command if it starts with a 'INSERT' statement.
    if query.len() > 6 && query[..6].eq_ignore_ascii_case("INSERT") {
        return None;
    }

    // First to check the query is like "select @@variables".
    check_select_variable(query, query_ctx.clone())
        // Then to check "show variables like ...".
        .or_else(|| check_show_variables(query))
        // Last check
        .or_else(|| check_others(query, query_ctx))
}

#[cfg(test)]
mod test {

    use common_query::OutputData;
    use common_time::timezone::set_default_timezone;
    use session::context::{Channel, QueryContext};
    use session::Session;

    use super::*;

    #[test]
    fn test_check() {
        let session = Arc::new(Session::new(None, Channel::Mysql, Default::default()));
        let query = "select 1";
        let result = check(query, QueryContext::arc(), session.clone());
        assert!(result.is_none());

        let query = "select version";
        let output = check(query, QueryContext::arc(), session.clone());
        assert!(output.is_none());

        fn test(query: &str, expected: &str) {
            let session = Arc::new(Session::new(None, Channel::Mysql, Default::default()));
            let output = check(query, QueryContext::arc(), session.clone());
            match output.unwrap().data {
                OutputData::RecordBatches(r) => {
                    assert_eq!(&r.pretty_print().unwrap(), expected)
                }
                _ => unreachable!(),
            }
        }

        let query = "SELECT @@version_comment LIMIT 1";
        let expected = "\
+-------------------+
| @@version_comment |
+-------------------+
| Greptime          |
+-------------------+";
        test(query, expected);

        // variables
        let query = "select @@tx_isolation, @@session.tx_isolation";
        let expected = "\
+-----------------+------------------------+
| @@tx_isolation  | @@session.tx_isolation |
+-----------------+------------------------+
| REPEATABLE-READ | REPEATABLE-READ        |
+-----------------+------------------------+";
        test(query, expected);

        // set system timezone
        set_default_timezone(Some("Asia/Shanghai")).unwrap();
        // complex variables
        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;";
        let expected = "\
+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+
| 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; |
+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+
| 0                        | 0                    | 0                        | 0                     | 0                    | 0                | 0                    | 0            | 31536000            | 0       | 0                      | 134217728          | 31536000          | 0                  | 0        | Asia/Shanghai    | Asia/Shanghai | REPEATABLE-READ       | 31536000      |
+--------------------------+----------------------+--------------------------+-----------------------+----------------------+------------------+----------------------+--------------+---------------------+---------+------------------------+--------------------+-------------------+--------------------+----------+------------------+---------------+-----------------------+---------------+";
        test(query, expected);

        let query = "show variables";
        let expected = "\
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
|               |       |
+---------------+-------+";
        test(query, expected);

        let query = "show variables like 'lower_case_table_names'";
        let expected = "\
+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| lower_case_table_names | 0     |
+------------------------+-------+";
        test(query, expected);

        let query = "SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP())";
        let expected = "\
+----------------------------------+
| TIMEDIFF(NOW(), UTC_TIMESTAMP()) |
+----------------------------------+
| 00:00:00                         |
+----------------------------------+";
        test(query, expected);
    }
}