rocksdb/
snapshot.rs

1// Copyright 2020 Tyler Neely
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
15use crate::{
16    db::DBAccess, ffi, AsColumnFamilyRef, DBIteratorWithThreadMode, DBPinnableSlice,
17    DBRawIteratorWithThreadMode, Error, IteratorMode, ReadOptions, DB,
18};
19
20/// A type alias to keep compatibility. See [`SnapshotWithThreadMode`] for details
21pub type Snapshot<'a> = SnapshotWithThreadMode<'a, DB>;
22
23/// A consistent view of the database at the point of creation.
24///
25/// # Examples
26///
27/// ```
28/// use rocksdb::{DB, IteratorMode, Options};
29///
30/// let tempdir = tempfile::Builder::new()
31///     .prefix("_path_for_rocksdb_storage3")
32///     .tempdir()
33///     .expect("Failed to create temporary path for the _path_for_rocksdb_storage3");
34/// let path = tempdir.path();
35/// {
36///     let db = DB::open_default(path).unwrap();
37///     let snapshot = db.snapshot(); // Creates a longer-term snapshot of the DB, but closed when goes out of scope
38///     let mut iter = snapshot.iterator(IteratorMode::Start); // Make as many iterators as you'd like from one snapshot
39/// }
40/// let _ = DB::destroy(&Options::default(), path);
41/// ```
42///
43pub struct SnapshotWithThreadMode<'a, D: DBAccess> {
44    db: &'a D,
45    pub(crate) inner: *const ffi::rocksdb_snapshot_t,
46}
47
48impl<'a, D: DBAccess> SnapshotWithThreadMode<'a, D> {
49    /// Creates a new `SnapshotWithThreadMode` of the database `db`.
50    pub fn new(db: &'a D) -> Self {
51        let snapshot = unsafe { db.create_snapshot() };
52        Self {
53            db,
54            inner: snapshot,
55        }
56    }
57
58    /// Returns the sequence number of the snapshot.
59    pub fn sequence_number(&self) -> u64 {
60        unsafe { ffi::rocksdb_snapshot_get_sequence_number(self.inner) }
61    }
62
63    /// Creates an iterator over the data in this snapshot, using the default read options.
64    pub fn iterator(&self, mode: IteratorMode) -> DBIteratorWithThreadMode<'a, D> {
65        let readopts = ReadOptions::default();
66        self.iterator_opt(mode, readopts)
67    }
68
69    /// Creates an iterator over the data in this snapshot under the given column family, using
70    /// the default read options.
71    pub fn iterator_cf(
72        &self,
73        cf_handle: &impl AsColumnFamilyRef,
74        mode: IteratorMode,
75    ) -> DBIteratorWithThreadMode<D> {
76        let readopts = ReadOptions::default();
77        self.iterator_cf_opt(cf_handle, readopts, mode)
78    }
79
80    /// Creates an iterator over the data in this snapshot, using the given read options.
81    pub fn iterator_opt(
82        &self,
83        mode: IteratorMode,
84        mut readopts: ReadOptions,
85    ) -> DBIteratorWithThreadMode<'a, D> {
86        readopts.set_snapshot(self);
87        DBIteratorWithThreadMode::<D>::new(self.db, readopts, mode)
88    }
89
90    /// Creates an iterator over the data in this snapshot under the given column family, using
91    /// the given read options.
92    pub fn iterator_cf_opt(
93        &self,
94        cf_handle: &impl AsColumnFamilyRef,
95        mut readopts: ReadOptions,
96        mode: IteratorMode,
97    ) -> DBIteratorWithThreadMode<D> {
98        readopts.set_snapshot(self);
99        DBIteratorWithThreadMode::new_cf(self.db, cf_handle.inner(), readopts, mode)
100    }
101
102    /// Creates a raw iterator over the data in this snapshot, using the default read options.
103    pub fn raw_iterator(&self) -> DBRawIteratorWithThreadMode<D> {
104        let readopts = ReadOptions::default();
105        self.raw_iterator_opt(readopts)
106    }
107
108    /// Creates a raw iterator over the data in this snapshot under the given column family, using
109    /// the default read options.
110    pub fn raw_iterator_cf(
111        &self,
112        cf_handle: &impl AsColumnFamilyRef,
113    ) -> DBRawIteratorWithThreadMode<D> {
114        let readopts = ReadOptions::default();
115        self.raw_iterator_cf_opt(cf_handle, readopts)
116    }
117
118    /// Creates a raw iterator over the data in this snapshot, using the given read options.
119    pub fn raw_iterator_opt(&self, mut readopts: ReadOptions) -> DBRawIteratorWithThreadMode<D> {
120        readopts.set_snapshot(self);
121        DBRawIteratorWithThreadMode::new(self.db, readopts)
122    }
123
124    /// Creates a raw iterator over the data in this snapshot under the given column family, using
125    /// the given read options.
126    pub fn raw_iterator_cf_opt(
127        &self,
128        cf_handle: &impl AsColumnFamilyRef,
129        mut readopts: ReadOptions,
130    ) -> DBRawIteratorWithThreadMode<D> {
131        readopts.set_snapshot(self);
132        DBRawIteratorWithThreadMode::new_cf(self.db, cf_handle.inner(), readopts)
133    }
134
135    /// Returns the bytes associated with a key value with default read options.
136    pub fn get<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<Vec<u8>>, Error> {
137        let readopts = ReadOptions::default();
138        self.get_opt(key, readopts)
139    }
140
141    /// Returns the bytes associated with a key value and given column family with default read
142    /// options.
143    pub fn get_cf<K: AsRef<[u8]>>(
144        &self,
145        cf: &impl AsColumnFamilyRef,
146        key: K,
147    ) -> Result<Option<Vec<u8>>, Error> {
148        let readopts = ReadOptions::default();
149        self.get_cf_opt(cf, key.as_ref(), readopts)
150    }
151
152    /// Returns the bytes associated with a key value and given read options.
153    pub fn get_opt<K: AsRef<[u8]>>(
154        &self,
155        key: K,
156        mut readopts: ReadOptions,
157    ) -> Result<Option<Vec<u8>>, Error> {
158        readopts.set_snapshot(self);
159        self.db.get_opt(key.as_ref(), &readopts)
160    }
161
162    /// Returns the bytes associated with a key value, given column family and read options.
163    pub fn get_cf_opt<K: AsRef<[u8]>>(
164        &self,
165        cf: &impl AsColumnFamilyRef,
166        key: K,
167        mut readopts: ReadOptions,
168    ) -> Result<Option<Vec<u8>>, Error> {
169        readopts.set_snapshot(self);
170        self.db.get_cf_opt(cf, key.as_ref(), &readopts)
171    }
172
173    /// Return the value associated with a key using RocksDB's PinnableSlice
174    /// so as to avoid unnecessary memory copy. Similar to get_pinned_opt but
175    /// leverages default options.
176    pub fn get_pinned<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<DBPinnableSlice>, Error> {
177        let readopts = ReadOptions::default();
178        self.get_pinned_opt(key, readopts)
179    }
180
181    /// Return the value associated with a key using RocksDB's PinnableSlice
182    /// so as to avoid unnecessary memory copy. Similar to get_pinned_cf_opt but
183    /// leverages default options.
184    pub fn get_pinned_cf<K: AsRef<[u8]>>(
185        &self,
186        cf: &impl AsColumnFamilyRef,
187        key: K,
188    ) -> Result<Option<DBPinnableSlice>, Error> {
189        let readopts = ReadOptions::default();
190        self.get_pinned_cf_opt(cf, key.as_ref(), readopts)
191    }
192
193    /// Return the value associated with a key using RocksDB's PinnableSlice
194    /// so as to avoid unnecessary memory copy.
195    pub fn get_pinned_opt<K: AsRef<[u8]>>(
196        &self,
197        key: K,
198        mut readopts: ReadOptions,
199    ) -> Result<Option<DBPinnableSlice>, Error> {
200        readopts.set_snapshot(self);
201        self.db.get_pinned_opt(key.as_ref(), &readopts)
202    }
203
204    /// Return the value associated with a key using RocksDB's PinnableSlice
205    /// so as to avoid unnecessary memory copy. Similar to get_pinned_opt but
206    /// allows specifying ColumnFamily.
207    pub fn get_pinned_cf_opt<K: AsRef<[u8]>>(
208        &self,
209        cf: &impl AsColumnFamilyRef,
210        key: K,
211        mut readopts: ReadOptions,
212    ) -> Result<Option<DBPinnableSlice>, Error> {
213        readopts.set_snapshot(self);
214        self.db.get_pinned_cf_opt(cf, key.as_ref(), &readopts)
215    }
216
217    /// Returns the bytes associated with the given key values and default read options.
218    pub fn multi_get<K: AsRef<[u8]>, I>(&self, keys: I) -> Vec<Result<Option<Vec<u8>>, Error>>
219    where
220        I: IntoIterator<Item = K>,
221    {
222        let readopts = ReadOptions::default();
223        self.multi_get_opt(keys, readopts)
224    }
225
226    /// Returns the bytes associated with the given key values and default read options.
227    pub fn multi_get_cf<'b, K, I, W>(&self, keys_cf: I) -> Vec<Result<Option<Vec<u8>>, Error>>
228    where
229        K: AsRef<[u8]>,
230        I: IntoIterator<Item = (&'b W, K)>,
231        W: AsColumnFamilyRef + 'b,
232    {
233        let readopts = ReadOptions::default();
234        self.multi_get_cf_opt(keys_cf, readopts)
235    }
236
237    /// Returns the bytes associated with the given key values and given read options.
238    pub fn multi_get_opt<K, I>(
239        &self,
240        keys: I,
241        mut readopts: ReadOptions,
242    ) -> Vec<Result<Option<Vec<u8>>, Error>>
243    where
244        K: AsRef<[u8]>,
245        I: IntoIterator<Item = K>,
246    {
247        readopts.set_snapshot(self);
248        self.db.multi_get_opt(keys, &readopts)
249    }
250
251    /// Returns the bytes associated with the given key values, given column family and read options.
252    pub fn multi_get_cf_opt<'b, K, I, W>(
253        &self,
254        keys_cf: I,
255        mut readopts: ReadOptions,
256    ) -> Vec<Result<Option<Vec<u8>>, Error>>
257    where
258        K: AsRef<[u8]>,
259        I: IntoIterator<Item = (&'b W, K)>,
260        W: AsColumnFamilyRef + 'b,
261    {
262        readopts.set_snapshot(self);
263        self.db.multi_get_cf_opt(keys_cf, &readopts)
264    }
265}
266
267impl<D: DBAccess> Drop for SnapshotWithThreadMode<'_, D> {
268    fn drop(&mut self) {
269        unsafe {
270            self.db.release_snapshot(self.inner);
271        }
272    }
273}
274
275/// `Send` and `Sync` implementations for `SnapshotWithThreadMode` are safe, because `SnapshotWithThreadMode` is
276/// immutable and can be safely shared between threads.
277unsafe impl<D: DBAccess> Send for SnapshotWithThreadMode<'_, D> {}
278unsafe impl<D: DBAccess> Sync for SnapshotWithThreadMode<'_, D> {}
rocksdb/snapshot.rs

rocksdb/
snapshot.rs
