mirror of https://github.com/nextgraph-org/rkv.git
support architecture-independent database migration (#142)
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fec68c0379
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// Copyright 2018-2019 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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extern crate rkv; |
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use rkv::{ |
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error::MigrateError, |
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migrate::Migrator, |
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}; |
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use std::{ |
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env::args, |
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io, |
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path::Path, |
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}; |
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fn main() -> Result<(), MigrateError> { |
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let mut cli_args = args(); |
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let mut db_name = None; |
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let mut env_path = None; |
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// The first arg is the name of the program, which we can ignore.
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cli_args.next(); |
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while let Some(arg) = cli_args.next() { |
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if &arg[0..1] == "-" { |
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match &arg[1..] { |
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"s" => { |
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db_name = match cli_args.next() { |
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None => return Err("-s must be followed by database name".into()), |
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Some(str) => Some(str), |
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}; |
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}, |
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str => return Err(format!("arg -{} not recognized", str).into()), |
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} |
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} else { |
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if env_path.is_some() { |
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return Err("must provide only one path to the LMDB environment".into()); |
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} |
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env_path = Some(arg); |
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} |
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} |
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let env_path = env_path.ok_or("must provide a path to the LMDB environment")?; |
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let mut migrator: Migrator = Migrator::new(Path::new(&env_path))?; |
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migrator.dump(db_name.as_ref().map(String::as_str), io::stdout()).unwrap(); |
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Ok(()) |
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} |
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// Copyright 2018-2019 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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//! A command-line utility to create an LMDB environment containing random data.
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//! It requires one flag, `-s path/to/environment`, which specifies the location
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//! where the tool should create the environment. Optionally, you may specify
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//! the number of key/value pairs to create via the `-n <number>` flag
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//! (for which the default value is 50).
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extern crate rkv; |
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use rkv::{ |
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Rkv, |
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SingleStore, |
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StoreOptions, |
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Value, |
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}; |
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use std::{ |
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env::args, |
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fs::{ |
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create_dir_all, |
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File, |
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}, |
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io::Read, |
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path::Path, |
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}; |
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fn main() { |
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let mut args = args(); |
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let mut database = None; |
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let mut path = None; |
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let mut num_pairs = 50; |
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// The first arg is the name of the program, which we can ignore.
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args.next(); |
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while let Some(arg) = args.next() { |
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if &arg[0..1] == "-" { |
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match &arg[1..] { |
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"s" => { |
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database = match args.next() { |
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None => panic!("-s must be followed by database arg"), |
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Some(str) => Some(str), |
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}; |
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}, |
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"n" => { |
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num_pairs = match args.next() { |
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None => panic!("-s must be followed by number of pairs"), |
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Some(str) => str.parse().expect("number"), |
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}; |
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}, |
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str => panic!("arg -{} not recognized", str), |
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} |
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} else { |
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if path.is_some() { |
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panic!("must provide only one path to the LMDB environment"); |
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} |
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path = Some(arg); |
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} |
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} |
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if path.is_none() { |
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panic!("must provide a path to the LMDB environment"); |
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} |
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let path = path.unwrap(); |
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create_dir_all(&path).expect("dir created"); |
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let mut builder = Rkv::environment_builder(); |
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builder.set_max_dbs(2); |
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// Allocate enough map to accommodate the largest random collection.
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// We currently do this by allocating twice the maximum possible size
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// of the pairs (assuming maximum key and value sizes).
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builder.set_map_size((511 + 65535) * num_pairs * 2); |
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let rkv = Rkv::from_env(Path::new(&path), builder).expect("Rkv"); |
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let store: SingleStore = |
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rkv.open_single(database.as_ref().map(|x| x.as_str()), StoreOptions::create()).expect("opened"); |
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let mut writer = rkv.write().expect("writer"); |
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// Generate random values for the number of keys and key/value lengths.
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// On Linux, "Just use /dev/urandom!" <https://www.2uo.de/myths-about-urandom/>.
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// On macOS it doesn't matter (/dev/random and /dev/urandom are identical).
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let mut random = File::open("/dev/urandom").unwrap(); |
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let mut nums = [0u8; 4]; |
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random.read_exact(&mut nums).unwrap(); |
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// Generate 0–255 pairs.
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for _ in 0..num_pairs { |
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// Generate key and value lengths. The key must be 1–511 bytes long.
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// The value length can be 0 and is essentially unbounded; we generate
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// value lengths of 0–0xffff (65535).
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// NB: the modulus method for generating a random number within a range
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// introduces distribution skew, but we don't need it to be perfect.
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let key_len = ((u16::from(nums[0]) + (u16::from(nums[1]) << 8)) % 511 + 1) as usize; |
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let value_len = (u16::from(nums[2]) + (u16::from(nums[3]) << 8)) as usize; |
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let mut key: Vec<u8> = vec![0; key_len]; |
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random.read_exact(&mut key[0..key_len]).unwrap(); |
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let mut value: Vec<u8> = vec![0; value_len]; |
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random.read_exact(&mut value[0..value_len]).unwrap(); |
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store.put(&mut writer, key, &Value::Blob(&value)).expect("wrote"); |
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} |
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writer.commit().expect("committed"); |
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} |
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VERSION=3 |
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format=bytevalue |
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type=btree |
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mapsize=6604600 |
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maxreaders=126 |
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db_pagesize=4096 |
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HEADER=END |
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DATA=END |
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