session/
lib.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
15pub mod context;
16pub mod hints;
17pub mod protocol_ctx;
18pub mod query_id;
19pub mod session_config;
20pub mod table_name;
21
22use std::collections::{HashMap, VecDeque};
23use std::net::SocketAddr;
24use std::sync::{Arc, RwLock};
25use std::time::Duration;
26
27use auth::UserInfoRef;
28use common_catalog::build_db_string;
29use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
30use common_recordbatch::cursor::RecordBatchStreamCursor;
31pub use common_session::ReadPreference;
32use common_time::Timezone;
33use common_time::timezone::get_timezone;
34use context::{ConfigurationVariables, QueryContextBuilder};
35use derive_more::Debug;
36
37use crate::context::{Channel, ConnInfo, QueryContextRef, dialect_for_channel};
38
39/// Maximum number of warnings to store per session (similar to MySQL's max_error_count)
40const MAX_WARNINGS: usize = 64;
41
42/// Session for persistent connection such as MySQL, PostgreSQL etc.
43#[derive(Debug)]
44pub struct Session {
45    catalog: RwLock<String>,
46    mutable_inner: Arc<RwLock<MutableInner>>,
47    conn_info: ConnInfo,
48    configuration_variables: Arc<ConfigurationVariables>,
49    // the process id to use when killing the query
50    process_id: u32,
51}
52
53pub type SessionRef = Arc<Session>;
54
55/// A container for mutable items in query context
56#[derive(Debug, Clone)]
57pub(crate) struct MutableInner {
58    schema: String,
59    user_info: UserInfoRef,
60    timezone: Timezone,
61    query_timeout: Option<Duration>,
62    read_preference: ReadPreference,
63    #[debug(skip)]
64    pub(crate) cursors: HashMap<String, Arc<RecordBatchStreamCursor>>,
65    /// Warning messages for MySQL SHOW WARNINGS support
66    warnings: VecDeque<String>,
67}
68
69impl Default for MutableInner {
70    fn default() -> Self {
71        Self {
72            schema: DEFAULT_SCHEMA_NAME.into(),
73            user_info: auth::userinfo_by_name(None),
74            timezone: get_timezone(None).clone(),
75            query_timeout: None,
76            read_preference: ReadPreference::Leader,
77            cursors: HashMap::with_capacity(0),
78            warnings: VecDeque::new(),
79        }
80    }
81}
82
83impl Session {
84    pub fn new(
85        addr: Option<SocketAddr>,
86        channel: Channel,
87        configuration_variables: ConfigurationVariables,
88        process_id: u32,
89    ) -> Self {
90        Session {
91            catalog: RwLock::new(DEFAULT_CATALOG_NAME.into()),
92            conn_info: ConnInfo::new(addr, channel),
93            configuration_variables: Arc::new(configuration_variables),
94            mutable_inner: Arc::new(RwLock::new(MutableInner::default())),
95            process_id,
96        }
97    }
98
99    pub fn new_query_context(&self) -> QueryContextRef {
100        QueryContextBuilder::default()
101            // catalog is not allowed for update in query context so we use
102            // string here
103            .current_catalog(self.catalog.read().unwrap().clone())
104            .mutable_session_data(self.mutable_inner.clone())
105            .sql_dialect(dialect_for_channel(self.conn_info.channel))
106            .configuration_parameter(self.configuration_variables.clone())
107            .channel(self.conn_info.channel)
108            .process_id(self.process_id)
109            .conn_info(self.conn_info.clone())
110            .build()
111            .into()
112    }
113
114    /// Cursors are shared across query contexts created from this session.
115    pub fn get_cursor(&self, name: &str) -> Option<Arc<RecordBatchStreamCursor>> {
116        let guard = self.mutable_inner.read().unwrap();
117        guard.cursors.get(name).cloned()
118    }
119
120    pub fn conn_info(&self) -> &ConnInfo {
121        &self.conn_info
122    }
123
124    pub fn timezone(&self) -> Timezone {
125        self.mutable_inner.read().unwrap().timezone.clone()
126    }
127
128    pub fn read_preference(&self) -> ReadPreference {
129        self.mutable_inner.read().unwrap().read_preference
130    }
131
132    pub fn set_timezone(&self, tz: Timezone) {
133        let mut inner = self.mutable_inner.write().unwrap();
134        inner.timezone = tz;
135    }
136
137    pub fn set_read_preference(&self, read_preference: ReadPreference) {
138        self.mutable_inner.write().unwrap().read_preference = read_preference;
139    }
140
141    pub fn user_info(&self) -> UserInfoRef {
142        self.mutable_inner.read().unwrap().user_info.clone()
143    }
144
145    pub fn set_user_info(&self, user_info: UserInfoRef) {
146        self.mutable_inner.write().unwrap().user_info = user_info;
147    }
148
149    pub fn set_catalog(&self, catalog: String) {
150        *self.catalog.write().unwrap() = catalog;
151    }
152
153    pub fn catalog(&self) -> String {
154        self.catalog.read().unwrap().clone()
155    }
156
157    pub fn schema(&self) -> String {
158        self.mutable_inner.read().unwrap().schema.clone()
159    }
160
161    pub fn set_schema(&self, schema: String) {
162        self.mutable_inner.write().unwrap().schema = schema;
163    }
164
165    pub fn get_db_string(&self) -> String {
166        build_db_string(&self.catalog(), &self.schema())
167    }
168
169    pub fn process_id(&self) -> u32 {
170        self.process_id
171    }
172
173    pub fn warnings_count(&self) -> usize {
174        self.mutable_inner.read().unwrap().warnings.len()
175    }
176
177    pub fn warnings(&self) -> Vec<String> {
178        self.mutable_inner
179            .read()
180            .unwrap()
181            .warnings
182            .iter()
183            .cloned()
184            .collect()
185    }
186
187    /// Add a warning message. If the limit is reached, discard the oldest warning.
188    pub fn add_warning(&self, warning: String) {
189        let mut inner = self.mutable_inner.write().unwrap();
190        if inner.warnings.len() >= MAX_WARNINGS {
191            inner.warnings.pop_front();
192        }
193        inner.warnings.push_back(warning);
194    }
195
196    pub fn clear_warnings(&self) {
197        let mut inner = self.mutable_inner.write().unwrap();
198        if inner.warnings.is_empty() {
199            return;
200        }
201        inner.warnings.clear();
202    }
203}
session/lib.rs

session/
lib.rs
