forked from tikv/tikv
/
writer.rs
300 lines (277 loc) · 9.55 KB
/
writer.rs
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// Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0.
use std::sync::Arc;
use std::time::Instant;
use engine::rocks::{SstWriter, SstWriterBuilder};
use engine::{CF_DEFAULT, CF_WRITE, DB};
use external_storage::ExternalStorage;
use futures_util::io::AllowStdIo;
use kvproto::backup::File;
use tikv::coprocessor::checksum_crc64_xor;
use tikv::raftstore::store::keys;
use tikv::storage::txn::TxnEntry;
use tikv_util::{self, box_err, file::Sha256Reader, time::Limiter};
use crate::metrics::*;
use crate::{Error, Result};
struct Writer {
writer: SstWriter,
total_kvs: u64,
total_bytes: u64,
checksum: u64,
digest: crc64fast::Digest,
}
impl Writer {
fn new(writer: SstWriter) -> Self {
Writer {
writer,
total_kvs: 0,
total_bytes: 0,
checksum: 0,
digest: crc64fast::Digest::new(),
}
}
fn write(&mut self, key: &[u8], value: &[u8]) -> Result<()> {
// HACK: The actual key stored in TiKV is called
// data_key and always prefix a `z`. But iterator strips
// it, we need to add the prefix manually.
let data_key_write = keys::data_key(key);
self.writer.put(&data_key_write, value)?;
Ok(())
}
fn update_with(&mut self, entry: TxnEntry, need_checksum: bool) -> Result<()> {
self.total_kvs += 1;
if need_checksum {
let (k, v) = entry
.into_kvpair()
.map_err(|err| Error::Other(box_err!("Decode error: {:?}", err)))?;
self.total_bytes += (k.len() + v.len()) as u64;
self.checksum = checksum_crc64_xor(self.checksum, self.digest.clone(), &k, &v);
}
Ok(())
}
fn save_and_build_file(
self,
name: &str,
cf: &'static str,
limiter: Limiter,
storage: &dyn ExternalStorage,
) -> Result<File> {
let (sst_info, sst_reader) = self.writer.finish_read()?;
BACKUP_RANGE_SIZE_HISTOGRAM_VEC
.with_label_values(&[cf])
.observe(sst_info.file_size() as f64);
let file_name = format!("{}_{}.sst", name, cf);
let (reader, hasher) = Sha256Reader::new(sst_reader)
.map_err(|e| Error::Other(box_err!("Sha256 error: {:?}", e)))?;
storage.write(
&file_name,
Box::new(limiter.limit(AllowStdIo::new(reader))),
sst_info.file_size(),
)?;
let sha256 = hasher
.lock()
.unwrap()
.finish()
.map(|digest| digest.to_vec())
.map_err(|e| Error::Other(box_err!("Sha256 error: {:?}", e)))?;
let mut file = File::new();
file.set_name(file_name);
file.set_sha256(sha256);
file.set_crc64xor(self.checksum);
file.set_total_kvs(self.total_kvs);
file.set_total_bytes(self.total_bytes);
Ok(file)
}
fn is_empty(&self) -> bool {
self.total_kvs == 0
}
}
/// A writer writes txn entries into SST files.
pub struct BackupWriter {
name: String,
default: Writer,
write: Writer,
limiter: Limiter,
}
impl BackupWriter {
/// Create a new BackupWriter.
pub fn new(db: Arc<DB>, name: &str, limiter: Limiter) -> Result<BackupWriter> {
let default = SstWriterBuilder::new()
.set_in_memory(true)
.set_cf(CF_DEFAULT)
.set_db(db.clone())
.build(name)?;
let write = SstWriterBuilder::new()
.set_in_memory(true)
.set_cf(CF_WRITE)
.set_db(db.clone())
.build(name)?;
let name = name.to_owned();
Ok(BackupWriter {
name,
default: Writer::new(default),
write: Writer::new(write),
limiter,
})
}
/// Write entries to buffered SST files.
pub fn write<I>(&mut self, entries: I, need_checksum: bool) -> Result<()>
where
I: Iterator<Item = TxnEntry>,
{
for e in entries {
let mut value_in_default = false;
match &e {
TxnEntry::Commit { default, write } => {
// Default may be empty if value is small.
if !default.0.is_empty() {
self.default.write(&default.0, &default.1)?;
value_in_default = true;
}
assert!(!write.0.is_empty());
self.write.write(&write.0, &write.1)?;
}
TxnEntry::Prewrite { .. } => {
return Err(Error::Other("prewrite is not supported".into()));
}
}
if value_in_default {
self.default.update_with(e, need_checksum)?;
} else {
self.write.update_with(e, need_checksum)?;
}
}
Ok(())
}
/// Save buffered SST files to the given external storage.
pub fn save(self, storage: &dyn ExternalStorage) -> Result<Vec<File>> {
let start = Instant::now();
let mut files = Vec::with_capacity(2);
let write_written = !self.write.is_empty() || !self.default.is_empty();
if !self.default.is_empty() {
// Save default cf contents.
let default = self.default.save_and_build_file(
&self.name,
CF_DEFAULT,
self.limiter.clone(),
storage,
)?;
files.push(default);
}
if write_written {
// Save write cf contents.
let write = self.write.save_and_build_file(
&self.name,
CF_WRITE,
self.limiter.clone(),
storage,
)?;
files.push(write);
}
BACKUP_RANGE_HISTOGRAM_VEC
.with_label_values(&["save"])
.observe(start.elapsed().as_secs_f64());
Ok(files)
}
}
#[cfg(test)]
mod tests {
use super::*;
use engine::Iterable;
use std::collections::BTreeMap;
use std::f64::INFINITY;
use std::path::Path;
use tempfile::TempDir;
use tikv::storage::TestEngineBuilder;
type CfKvs<'a> = (engine::CfName, &'a [(&'a [u8], &'a [u8])]);
fn check_sst(ssts: &[(engine::CfName, &Path)], kvs: &[CfKvs<'_>]) {
let temp = TempDir::new().unwrap();
let rocks = TestEngineBuilder::new()
.path(temp.path())
.cfs(&[engine::CF_DEFAULT, engine::CF_WRITE])
.build()
.unwrap();
let db = rocks.get_rocksdb();
let opt = engine::rocks::IngestExternalFileOptions::new();
for (cf, sst) in ssts {
let handle = db.cf_handle(cf).unwrap();
db.ingest_external_file_cf(handle, &opt, &[sst.to_str().unwrap()])
.unwrap();
}
for (cf, kv) in kvs {
let mut map = BTreeMap::new();
db.scan_cf(
cf,
keys::DATA_MIN_KEY,
keys::DATA_MAX_KEY,
false,
|key, value| {
map.insert(key.to_owned(), value.to_owned());
Ok(true)
},
)
.unwrap();
assert_eq!(map.len(), kv.len(), "{:?} {:?}", map, kv);
for (k, v) in *kv {
assert_eq!(&v.to_vec(), map.get(&k.to_vec()).unwrap());
}
}
}
#[test]
fn test_writer() {
let temp = TempDir::new().unwrap();
let rocks = TestEngineBuilder::new()
.path(temp.path())
.cfs(&[engine::CF_DEFAULT, engine::CF_LOCK, engine::CF_WRITE])
.build()
.unwrap();
let db = rocks.get_rocksdb();
let backend = external_storage::make_local_backend(temp.path());
let storage = external_storage::create_storage(&backend).unwrap();
// Test empty file.
let mut writer = BackupWriter::new(db.clone(), "foo", Limiter::new(INFINITY)).unwrap();
writer.write(vec![].into_iter(), false).unwrap();
assert!(writer.save(&storage).unwrap().is_empty());
// Test write only txn.
let mut writer = BackupWriter::new(db.clone(), "foo1", Limiter::new(INFINITY)).unwrap();
writer
.write(
vec![TxnEntry::Commit {
default: (vec![], vec![]),
write: (vec![b'a'], vec![b'a']),
}]
.into_iter(),
false,
)
.unwrap();
let files = writer.save(&storage).unwrap();
assert_eq!(files.len(), 1);
check_sst(
&[(engine::CF_WRITE, &temp.path().join(files[0].get_name()))],
&[(engine::CF_WRITE, &[(&keys::data_key(&[b'a']), &[b'a'])])],
);
// Test write and default.
let mut writer = BackupWriter::new(db, "foo2", Limiter::new(INFINITY)).unwrap();
writer
.write(
vec![TxnEntry::Commit {
default: (vec![b'a'], vec![b'a']),
write: (vec![b'a'], vec![b'a']),
}]
.into_iter(),
false,
)
.unwrap();
let files = writer.save(&storage).unwrap();
assert_eq!(files.len(), 2);
check_sst(
&[
(engine::CF_DEFAULT, &temp.path().join(files[0].get_name())),
(engine::CF_WRITE, &temp.path().join(files[1].get_name())),
],
&[
(engine::CF_DEFAULT, &[(&keys::data_key(&[b'a']), &[b'a'])]),
(engine::CF_WRITE, &[(&keys::data_key(&[b'a']), &[b'a'])]),
],
);
}
}