transaction: Add batch_mutate interface (tikv#418)

Signed-off-by: Ping Yu <yuping@pingcap.com>

Author: pingyu

src/transaction/buffer.rs

@@ -244,6 +244,15 @@ impl Buffer {
         }
     }
 
+    pub(crate) fn mutate(&mut self, m: kvrpcpb::Mutation) {
+        let op = kvrpcpb::Op::from_i32(m.op).unwrap();
+        match op {
+            kvrpcpb::Op::Put => self.put(m.key.into(), m.value),
+            kvrpcpb::Op::Del => self.delete(m.key.into()),
+            _ => unimplemented!("only put and delete are supported in mutate"),
+        };
+    }
+
     /// Converts the buffered mutations to the proto buffer version
     pub fn to_proto_mutations(&self) -> Vec<kvrpcpb::Mutation> {
         self.entry_map

src/transaction/transaction.rs

@@ -522,6 +522,56 @@ impl<Cod: Codec, PdC: PdClient<Codec = Cod>> Transaction<Cod, PdC> {
         Ok(())
     }
 
+    /// Batch mutate the database.
+    ///
+    /// Only `Put` and `Delete` are supported.
+    ///
+    /// # Examples
+    ///
+    /// ```rust,no_run
+    /// # use tikv_client::{Key, Config, TransactionClient, proto::kvrpcpb};
+    /// # use futures::prelude::*;
+    /// # futures::executor::block_on(async {
+    /// # let client = TransactionClient::new(vec!["192.168.0.100", "192.168.0.101"]).await.unwrap();
+    /// let mut txn = client.begin_optimistic().await.unwrap();
+    /// let mutations = vec![
+    ///     kvrpcpb::Mutation {
+    ///         op: kvrpcpb::Op::Del.into(),
+    ///         key: b"k0".to_vec(),
+    ///         ..Default::default()
+    ///     },
+    ///     kvrpcpb::Mutation {
+    ///         op: kvrpcpb::Op::Put.into(),
+    ///         key: b"k1".to_vec(),
+    ///         value: b"v1".to_vec(),
+    ///         ..Default::default()
+    ///     },
+    /// ];
+    /// txn.batch_mutate(mutations).await.unwrap();
+    /// txn.commit().await.unwrap();
+    /// # });
+    /// ```
+    pub async fn batch_mutate(
+        &mut self,
+        mutations: impl IntoIterator<Item = kvrpcpb::Mutation>,
+    ) -> Result<()> {
+        debug!("invoking transactional batch mutate request");
+        self.check_allow_operation().await?;
+        if self.is_pessimistic() {
+            let mutations: Vec<kvrpcpb::Mutation> = mutations.into_iter().collect();
+            self.pessimistic_lock(mutations.iter().map(|m| Key::from(m.key.clone())), false)
+                .await?;
+            for m in mutations {
+                self.buffer.mutate(m);
+            }
+        } else {
+            for m in mutations.into_iter() {
+                self.buffer.mutate(m);
+            }
+        }
+        Ok(())
+    }
+
     /// Lock the given keys without mutating their values.
     ///
     /// In optimistic mode, write conflicts are not checked until commit.

tests/common/mod.rs

@@ -10,12 +10,12 @@ use std::time::Duration;
 use log::info;
 use log::warn;
 use rand::Rng;
-use tikv_client::ColumnFamily;
 use tikv_client::Key;
 use tikv_client::RawClient;
 use tikv_client::Result;
 use tikv_client::Transaction;
 use tikv_client::TransactionClient;
+use tikv_client::{ColumnFamily, Snapshot, TransactionOptions};
 use tokio::time::sleep;
 
 const ENV_PD_ADDRS: &str = "PD_ADDRS";
@@ -147,6 +147,15 @@ pub fn gen_u32_keys(num: u32, rng: &mut impl Rng) -> HashSet<Vec<u8>> {
     set
 }
 
+pub async fn snapshot(client: &TransactionClient, is_pessimistic: bool) -> Result<Snapshot> {
+    let options = if is_pessimistic {
+        TransactionOptions::new_pessimistic()
+    } else {
+        TransactionOptions::new_optimistic()
+    };
+    Ok(client.snapshot(client.current_timestamp().await?, options))
+}
+
 /// Copied from https://github.com/tikv/tikv/blob/d86a449d7f5b656cef28576f166e73291f501d77/components/tikv_util/src/macros.rs#L55
 /// Simulates Go's defer.
 ///

tests/integration_tests.rs

@@ -21,8 +21,9 @@ use rand::seq::IteratorRandom;
 use rand::thread_rng;
 use rand::Rng;
 use serial_test::serial;
+use tikv_client::backoff::DEFAULT_REGION_BACKOFF;
+use tikv_client::proto::kvrpcpb;
 use tikv_client::transaction::HeartbeatOption;
-use tikv_client::BoundRange;
 use tikv_client::Error;
 use tikv_client::Key;
 use tikv_client::KvPair;
@@ -31,6 +32,7 @@ use tikv_client::Result;
 use tikv_client::TransactionClient;
 use tikv_client::TransactionOptions;
 use tikv_client::Value;
+use tikv_client::{Backoff, BoundRange, RetryOptions, Transaction};
 
 // Parameters used in test
 const NUM_PEOPLE: u32 = 100;
@@ -1078,3 +1080,123 @@ async fn txn_key_exists() -> Result<()> {
     t3.commit().await?;
     Ok(())
 }
+
+#[tokio::test]
+#[serial]
+async fn txn_batch_mutate_optimistic() -> Result<()> {
+    init().await?;
+    let client = TransactionClient::new(pd_addrs()).await?;
+
+    // Put k0
+    {
+        let mut txn = client.begin_optimistic().await?;
+        txn.put(b"k0".to_vec(), b"v0".to_vec()).await?;
+        txn.commit().await?;
+    }
+    // Delete k0 and put k1, k2
+    do_mutate(false).await.unwrap();
+    // Read and verify
+    verify_mutate(false).await;
+    Ok(())
+}
+
+#[tokio::test]
+#[serial]
+async fn txn_batch_mutate_pessimistic() -> Result<()> {
+    init().await?;
+    let client = TransactionClient::new(pd_addrs()).await?;
+
+    // Put k0
+    {
+        let mut txn = client.begin_pessimistic().await?;
+        txn.put(b"k0".to_vec(), b"v0".to_vec()).await?;
+        txn.commit().await?;
+    }
+    // txn1 lock k0, to verify pessimistic locking.
+    let mut txn1 = client.begin_pessimistic().await?;
+    txn1.put(b"k0".to_vec(), b"vv".to_vec()).await?;
+
+    // txn2 is blocked by txn1, then timeout.
+    let txn2_handle = tokio::spawn(do_mutate(true));
+    assert!(matches!(
+        txn2_handle.await?.unwrap_err(),
+        Error::PessimisticLockError { .. }
+    ));
+
+    let txn3_handle = tokio::spawn(do_mutate(true));
+    // txn1 rollback to release lock.
+    txn1.rollback().await?;
+    txn3_handle.await?.unwrap();
+
+    // Read and verify
+    verify_mutate(true).await;
+    Ok(())
+}
+
+async fn begin_mutate(client: &TransactionClient, is_pessimistic: bool) -> Result<Transaction> {
+    if is_pessimistic {
+        let options = TransactionOptions::new_pessimistic().retry_options(RetryOptions {
+            region_backoff: DEFAULT_REGION_BACKOFF,
+            lock_backoff: Backoff::no_jitter_backoff(500, 500, 2),
+        });
+        client.begin_with_options(options).await
+    } else {
+        client.begin_optimistic().await
+    }
+}
+
+async fn do_mutate(is_pessimistic: bool) -> Result<()> {
+    let client = TransactionClient::new(pd_addrs()).await.unwrap();
+    let mut txn = begin_mutate(&client, is_pessimistic).await.unwrap();
+
+    let mutations = vec![
+        kvrpcpb::Mutation {
+            op: kvrpcpb::Op::Del.into(),
+            key: b"k0".to_vec(),
+            ..Default::default()
+        },
+        kvrpcpb::Mutation {
+            op: kvrpcpb::Op::Put.into(),
+            key: b"k1".to_vec(),
+            value: b"v1".to_vec(),
+            ..Default::default()
+        },
+        kvrpcpb::Mutation {
+            op: kvrpcpb::Op::Put.into(),
+            key: b"k2".to_vec(),
+            value: b"v2".to_vec(),
+            ..Default::default()
+        },
+    ];
+
+    match txn.batch_mutate(mutations).await {
+        Ok(()) => {
+            txn.commit().await?;
+            Ok(())
+        }
+        Err(err) => {
+            let _ = txn.rollback().await;
+            Err(err)
+        }
+    }
+}
+
+async fn verify_mutate(is_pessimistic: bool) {
+    let client = TransactionClient::new(pd_addrs()).await.unwrap();
+    let mut snapshot = snapshot(&client, is_pessimistic).await.unwrap();
+    let res: HashMap<Key, Value> = snapshot
+        .batch_get(vec!["k0".to_owned(), "k1".to_owned(), "k2".to_owned()])
+        .await
+        .unwrap()
+        .map(|pair| (pair.0, pair.1))
+        .collect();
+    assert_eq!(res.len(), 2);
+    assert_eq!(
+        res.get(&Key::from("k1".to_owned())),
+        Some(Value::from("v1".to_owned())).as_ref()
+    );
+    assert_eq!(
+        res.get(&Key::from("k2".to_owned())),
+        Some(Value::from("v2".to_owned())).as_ref()
+    );
+}