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// Copyright Materialize, Inc. and contributors. All rights reserved.
//
// Use of this software is governed by the Business Source License
// included in the LICENSE file.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0.
//! Code to render the sink dataflow of a [`KafkaSinkConnection`]. The dataflow consists
//! of two operators in order to take advantage of all the available workers.
//!
//! ```text
//! ┏━━━━━━━━━━━━━━┓
//! ┃ persist ┃
//! ┃ source ┃
//! ┗━━━━━━┯━━━━━━━┛
//! │ row data, the input to this module
//! │
//! ┏━━━━━━v━━━━━━┓
//! ┃ row ┃
//! ┃ encoder ┃
//! ┗━━━━━━┯━━━━━━┛
//! │ encoded data
//! │
//! ┏━━━━━━v━━━━━━┓
//! ┃ kafka ┃ (single worker)
//! ┃ sink ┃
//! ┗━━┯━━━━━━━━┯━┛
//! records │ │ uppers
//! ╭────v──╮ ╭───v──────╮
//! │ data │ │ progress │ <- records and uppers are produced
//! │ topic │ │ topic │ transactionally to both topics
//! ╰───────╯ ╰──────────╯
//! ```
//!
//! # Encoding
//!
//! One part of the dataflow deals with encoding the rows that we read from persist. There isn't
//! anything surprizing here, it is *almost* just a `Collection::map` with the exception of an
//! initialization step that makes sure the schemas are published to the Schema Registry. After
//! that step the operator just encodes each batch it receives record by record.
//!
//! # Sinking
//!
//! The other part of the dataflow, and what this module mostly deals with, is interacting with the
//! Kafka cluster in order to transactionally commit batches (sets of records associated with a
//! frontier). All the processing happens in a single worker and so all previously encoded records
//! go through an exchange in order to arrive at the chosen worker. We may be able to improve this
//! in the future by committing disjoint partitions of the key space for independent workers but
//! for now we do the simple thing.
//!
//! ## Retries
//!
//! All of the retry logic heavy lifting is offloaded to `librdkafka` since it already implements
//! the required behavior[1]. In particular we only ever enqueue records to its send queue and
//! eventually call `commit_transaction` which will ensure that all queued messages are
//! successfully delivered before the transaction is reported as committed.
//!
//! The only error that is possible during sending is that the queue is full. We are purposefully
//! NOT handling this error and simply configure `librdkafka` with a very large queue. The reason
//! for this choice is that the only choice for hanlding such an error ourselves would be to queue
//! it, and there isn't a good argument about two small queues being better than one big one. If we
//! reach the queue limit we simply error out the entire sink dataflow and start over.
//!
//! # Error handling
//!
//! Both the encoding operator and the sinking operator can produce a transient error that is wired
//! up with our health monitoring and will trigger a restart of the sink dataflow.
//!
//! [1]: https://github.com/confluentinc/librdkafka/blob/master/INTRODUCTION.md#message-reliability
use std::cell::RefCell;
use std::cmp::Ordering;
use std::collections::BTreeMap;
use std::rc::Rc;
use std::sync::atomic::AtomicU64;
use std::sync::Arc;
use std::time::Duration;
use anyhow::{anyhow, bail, Context};
use differential_dataflow::{AsCollection, Collection, Hashable};
use futures::StreamExt;
use maplit::btreemap;
use mz_expr::MirScalarExpr;
use mz_interchange::avro::{AvroEncoder, DiffPair};
use mz_interchange::encode::Encode;
use mz_interchange::envelopes::dbz_format;
use mz_interchange::json::JsonEncoder;
use mz_interchange::text_binary::{BinaryEncoder, TextEncoder};
use mz_kafka_util::client::{
GetPartitionsError, MzClientContext, TimeoutConfig, TunnelingClientContext,
DEFAULT_FETCH_METADATA_TIMEOUT,
};
use mz_ore::cast::CastFrom;
use mz_ore::collections::CollectionExt;
use mz_ore::error::ErrorExt;
use mz_ore::future::InTask;
use mz_ore::task::{self, AbortOnDropHandle};
use mz_ore::vec::VecExt;
use mz_repr::{Datum, DatumVec, Diff, GlobalId, Row, RowArena, Timestamp};
use mz_storage_client::sink::progress_key::ProgressKey;
use mz_storage_types::configuration::StorageConfiguration;
use mz_storage_types::dyncfgs::KAFKA_BUFFERED_EVENT_RESIZE_THRESHOLD_ELEMENTS;
use mz_storage_types::errors::{ContextCreationError, ContextCreationErrorExt, DataflowError};
use mz_storage_types::sinks::{
KafkaSinkConnection, KafkaSinkFormatType, MetadataFilled, SinkEnvelope, SinkPartitionStrategy,
StorageSinkDesc,
};
use mz_timely_util::antichain::AntichainExt;
use mz_timely_util::builder_async::{
Event, OperatorBuilder as AsyncOperatorBuilder, PressOnDropButton,
};
use rdkafka::consumer::{BaseConsumer, Consumer};
use rdkafka::error::KafkaError;
use rdkafka::message::{Header, OwnedHeaders, ToBytes};
use rdkafka::producer::{BaseRecord, Producer, ThreadedProducer};
use rdkafka::types::RDKafkaErrorCode;
use rdkafka::{Message, Offset, Statistics, TopicPartitionList};
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use timely::dataflow::channels::pact::{Exchange, Pipeline};
use timely::dataflow::operators::{CapabilitySet, Concatenate, Map, ToStream};
use timely::dataflow::{Scope, Stream};
use timely::progress::{Antichain, Timestamp as _};
use timely::PartialOrder;
use tokio::sync::watch;
use tokio::time::{self, MissedTickBehavior};
use tracing::{error, info, warn};
use crate::healthcheck::{HealthStatusMessage, HealthStatusUpdate, StatusNamespace};
use crate::metrics::sink::kafka::KafkaSinkMetrics;
use crate::render::sinks::SinkRender;
use crate::statistics::SinkStatistics;
use crate::storage_state::StorageState;
impl<G: Scope<Timestamp = Timestamp>> SinkRender<G> for KafkaSinkConnection {
fn get_key_indices(&self) -> Option<&[usize]> {
self.key_desc_and_indices
.as_ref()
.map(|(_desc, indices)| indices.as_slice())
}
fn get_relation_key_indices(&self) -> Option<&[usize]> {
self.relation_key_indices.as_deref()
}
fn render_sink(
&self,
storage_state: &mut StorageState,
sink: &StorageSinkDesc<MetadataFilled, Timestamp>,
sink_id: GlobalId,
input: Collection<G, (Option<Row>, DiffPair<Row>), Diff>,
// TODO(benesch): errors should stream out through the sink,
// if we figure out a protocol for that.
_err_collection: Collection<G, DataflowError, Diff>,
) -> (Stream<G, HealthStatusMessage>, Vec<PressOnDropButton>) {
let mut scope = input.scope();
let write_frontier = Rc::new(RefCell::new(Antichain::from_elem(Timestamp::minimum())));
storage_state
.sink_write_frontiers
.insert(sink_id, Rc::clone(&write_frontier));
let (encoded, encode_status, encode_token) = encode_collection(
format!("kafka-{sink_id}-{}-encode", self.format.get_format_name()),
&input,
sink.envelope,
self.clone(),
storage_state.storage_configuration.clone(),
);
let metrics = storage_state.metrics.get_kafka_sink_metrics(sink_id);
let statistics = storage_state
.aggregated_statistics
.get_sink(&sink_id)
.expect("statistics initialized")
.clone();
let (sink_status, sink_token) = sink_collection(
format!("kafka-{sink_id}-sink"),
&encoded,
sink_id,
self.clone(),
sink.partition_strategy.clone(),
storage_state.storage_configuration.clone(),
sink,
metrics,
statistics,
write_frontier,
);
let running_status = Some(HealthStatusMessage {
index: 0,
update: HealthStatusUpdate::Running,
namespace: StatusNamespace::Kafka,
})
.to_stream(&mut scope);
let status = scope.concatenate([running_status, encode_status, sink_status]);
(status, vec![encode_token, sink_token])
}
}
struct TransactionalProducer {
/// The task name used for any blocking calls spawned onto the tokio threadpool.
task_name: String,
/// The topic where all the updates go.
data_topic: String,
/// The topic where all the upper frontiers go.
progress_topic: String,
/// The key each progress record is associated with.
progress_key: ProgressKey,
/// The version of this sink, used to fence out previous versions from writing.
sink_version: u64,
/// The strategy to partition the data with.
partition_strategy: SinkPartitionStrategy,
/// The number of partitions in the target topic.
partition_count: Arc<AtomicU64>,
/// A task to periodically refresh the partition count.
_partition_count_task: AbortOnDropHandle<()>,
/// The underlying Kafka producer.
producer: ThreadedProducer<TunnelingClientContext<MzClientContext>>,
/// A handle to the metrics associated with this sink.
statistics: SinkStatistics,
/// The number of messages staged for the currently open transactions. It is reset to zero
/// every time a transaction commits.
staged_messages: u64,
/// The total number bytes staged for the currently open transactions. It is reset to zero
/// every time a transaction commits.
staged_bytes: u64,
/// The timeout to use for network operations.
socket_timeout: Duration,
/// The timeout to use for committing transactions.
transaction_timeout: Duration,
}
impl TransactionalProducer {
/// Initializes a transcational producer for the sink identified by `sink_id`. After this call
/// returns it is guranteed that all previous `TransactionalProducer` instances for the same
/// sink have been fenced out (i.e `init_transations()` has been called successfully).
async fn new(
sink_id: GlobalId,
connection: &KafkaSinkConnection,
partition_strategy: SinkPartitionStrategy,
storage_configuration: &StorageConfiguration,
metrics: Arc<KafkaSinkMetrics>,
statistics: SinkStatistics,
sink_version: u64,
) -> Result<(Self, Antichain<mz_repr::Timestamp>), ContextCreationError> {
let client_id = connection.client_id(
storage_configuration.config_set(),
&storage_configuration.connection_context,
sink_id,
);
let transactional_id =
connection.transactional_id(&storage_configuration.connection_context, sink_id);
let timeout_config = &storage_configuration.parameters.kafka_timeout_config;
let mut options = BTreeMap::new();
// Ensure that messages are sinked in order and without duplicates. Note that this only
// applies to a single instance of a producer - in the case of restarts, all bets are off
// and full exactly once support is required.
options.insert("enable.idempotence", "true".into());
// Use the compression type requested by the user.
options.insert(
"compression.type",
connection.compression_type.to_librdkafka_option().into(),
);
// Set the maximum buffer size limit. We don't want to impose anything lower than the max
// here as the operator has nothing better to do with the data than to buffer them.
options.insert("queue.buffering.max.kbytes", "2147483647".into());
// Disable the default buffer limit of 100k messages. We don't want to impose any limit
// here as the operator has nothing better to do with the data than to buffer them.
options.insert("queue.buffering.max.messages", "0".into());
// Make the Kafka producer wait at least 10 ms before sending out MessageSets
options.insert("queue.buffering.max.ms", format!("{}", 10));
// Time out transactions after 60 seconds
options.insert(
"transaction.timeout.ms",
format!("{}", timeout_config.transaction_timeout.as_millis()),
);
// Use the transactional ID requested by the user.
options.insert("transactional.id", transactional_id);
// Allow Kafka monitoring tools to identify this producer.
options.insert("client.id", client_id);
// We want to be notified regularly with statistics
options.insert("statistics.interval.ms", "1000".into());
let ctx = MzClientContext::default();
let stats_receiver = ctx.subscribe_statistics();
let task_name = format!("kafka_sink_metrics_collector:{sink_id}");
task::spawn(
|| &task_name,
collect_statistics(stats_receiver, Arc::clone(&metrics)),
);
let producer: ThreadedProducer<_> = connection
.connection
.create_with_context(storage_configuration, ctx, &options, InTask::Yes)
.await?;
// The partition count is fixed up after we ensure the topic exists.
let partition_count = Arc::new(AtomicU64::new(0));
let update_partition_count = {
let partition_count = Arc::clone(&partition_count);
let metrics = Arc::clone(&metrics);
Arc::new(move |pc| {
partition_count.store(pc, std::sync::atomic::Ordering::SeqCst);
metrics.partition_count.set(pc);
})
};
// Start a task that will keep the partition count up to date in the
// background.
let partition_count_task = task::spawn(
|| format!("kafka_sink_producer_fetch_metadata_loop:{sink_id}"),
fetch_partition_count_loop(
producer.clone(),
sink_id,
connection.topic.clone(),
connection.topic_metadata_refresh_interval,
Arc::clone(&update_partition_count),
),
);
let task_name = format!("kafka_sink_producer:{sink_id}");
let progress_key = ProgressKey::new(sink_id);
let producer = Self {
task_name,
data_topic: connection.topic.clone(),
partition_strategy,
partition_count,
_partition_count_task: partition_count_task.abort_on_drop(),
progress_topic: connection
.progress_topic(&storage_configuration.connection_context)
.into_owned(),
progress_key,
sink_version,
producer,
statistics,
staged_messages: 0,
staged_bytes: 0,
socket_timeout: timeout_config.socket_timeout,
transaction_timeout: timeout_config.transaction_timeout,
};
let timeout = timeout_config.socket_timeout;
producer
.spawn_blocking(move |p| p.init_transactions(timeout))
.await?;
// We have just called init_transactions, which means that we have fenced out all previous
// transactional producers, making it safe to determine the resume upper.
let progress = determine_sink_progress(
sink_id,
connection,
storage_configuration,
Arc::clone(&metrics),
)
.await?;
let resume_upper = match progress {
Some(progress) => {
if sink_version < progress.version {
return Err(ContextCreationError::Other(anyhow!(
"Fenced off by newer version of the sink. ours={} theirs={}",
sink_version,
progress.version
)));
}
progress.frontier
}
None => {
mz_storage_client::sink::ensure_kafka_topic(
connection,
storage_configuration,
&connection.topic,
&connection.topic_options,
)
.await?;
Antichain::from_elem(Timestamp::minimum())
}
};
// At this point the topic must exist and so we can query for its
// partition count. Even though we have a background task to fetch the
// partition count, we do this synchronously to ensure we don't attempt
// to produce any messages with our initial partition count of 0.
let partition_count =
fetch_partition_count(&producer.producer, sink_id, &connection.topic).await?;
update_partition_count(partition_count);
Ok((producer, resume_upper))
}
/// Runs the blocking operation `f` on the producer in the tokio threadpool and checks for SSH
/// status in case of failure.
async fn spawn_blocking<F, R>(&self, f: F) -> Result<R, ContextCreationError>
where
F: FnOnce(
ThreadedProducer<TunnelingClientContext<MzClientContext>>,
) -> Result<R, KafkaError>
+ Send
+ 'static,
R: Send + 'static,
{
let producer = self.producer.clone();
task::spawn_blocking(|| &self.task_name, move || f(producer))
.await
.unwrap()
.check_ssh_status(self.producer.context())
}
async fn begin_transaction(&self) -> Result<(), ContextCreationError> {
self.spawn_blocking(|p| p.begin_transaction()).await
}
/// Synchronously puts the provided message to librdkafka's send queue. This method only
/// returns an error if the queue is full. Handling this error by buffering the message and
/// retrying is equivalent to adjusting the maximum number of queued items in rdkafka so it is
/// adviced that callers only handle this error in order to apply backpressure to the rest of
/// the system.
fn send(
&mut self,
message: &KafkaMessage,
time: Timestamp,
diff: Diff,
) -> Result<(), KafkaError> {
assert_eq!(diff, 1, "invalid sink update");
let mut headers = OwnedHeaders::new().insert(Header {
key: "materialize-timestamp",
value: Some(time.to_string().as_bytes()),
});
for header in &message.headers {
// Headers that start with `materialize-` are reserved for our
// internal use, so we silently drop any such user-specified
// headers. While this behavior is documented, it'd be a nicer UX to
// send a warning or error somewhere. Unfortunately sinks don't have
// anywhere user-visible to send errors. See database-issues#5148.
if header.key.starts_with("materialize-") {
continue;
}
headers = headers.insert(Header {
key: header.key.as_str(),
value: header.value.as_ref(),
});
}
let partition = match self.partition_strategy {
SinkPartitionStrategy::V0 => None,
SinkPartitionStrategy::V1 => {
let pc = self
.partition_count
.load(std::sync::atomic::Ordering::SeqCst);
Some(i32::try_from(message.hash % pc).unwrap())
}
};
let record = BaseRecord {
topic: &self.data_topic,
key: message.key.as_ref(),
payload: message.value.as_ref(),
headers: Some(headers),
partition,
timestamp: None,
delivery_opaque: (),
};
let key_size = message.key.as_ref().map(|k| k.len()).unwrap_or(0);
let value_size = message.value.as_ref().map(|k| k.len()).unwrap_or(0);
let headers_size = message
.headers
.iter()
.map(|h| h.key.len() + h.value.as_ref().map(|v| v.len()).unwrap_or(0))
.sum::<usize>();
let record_size = u64::cast_from(key_size + value_size + headers_size);
self.statistics.inc_messages_staged_by(1);
self.staged_messages += 1;
self.statistics.inc_bytes_staged_by(record_size);
self.staged_bytes += record_size;
self.producer.send(record).map_err(|(e, _)| e)
}
/// Commits all the staged updates of the currently open transaction plus a progress record
/// describing `upper` to the progress topic.
async fn commit_transaction(
&mut self,
upper: Antichain<Timestamp>,
) -> Result<(), ContextCreationError> {
let progress = ProgressRecord {
frontier: upper,
version: self.sink_version,
};
let payload = serde_json::to_vec(&progress).expect("infallible");
let record = BaseRecord::to(&self.progress_topic)
.payload(&payload)
.key(&self.progress_key);
self.producer.send(record).map_err(|(e, _)| e)?;
fail::fail_point!("kafka_sink_commit_transaction");
let timeout = self.transaction_timeout;
match self
.spawn_blocking(move |p| p.commit_transaction(timeout))
.await
{
Ok(()) => {
self.statistics
.inc_messages_committed_by(self.staged_messages);
self.statistics.inc_bytes_committed_by(self.staged_bytes);
self.staged_messages = 0;
self.staged_bytes = 0;
Ok(())
}
Err(ContextCreationError::KafkaError(KafkaError::Transaction(err))) => {
// Make one attempt at aborting the transaction before letting the error percolate
// up and the process exit. Aborting allows the consumers of the topic to skip over
// any messages we've written in the transaction, so it's polite to do... but if it
// fails, the transaction will be aborted either when fenced out by a future
// version of this producer or by the broker-side timeout.
if err.txn_requires_abort() {
let timeout = self.socket_timeout;
self.spawn_blocking(move |p| p.abort_transaction(timeout))
.await?;
}
Err(ContextCreationError::KafkaError(KafkaError::Transaction(
err,
)))
}
Err(err) => Err(err),
}
}
}
/// Listens for statistics updates from librdkafka and updates our Prometheus metrics.
async fn collect_statistics(
mut receiver: watch::Receiver<Statistics>,
metrics: Arc<KafkaSinkMetrics>,
) {
let mut outbuf_cnt: i64 = 0;
let mut outbuf_msg_cnt: i64 = 0;
let mut waitresp_cnt: i64 = 0;
let mut waitresp_msg_cnt: i64 = 0;
let mut txerrs: u64 = 0;
let mut txretries: u64 = 0;
let mut req_timeouts: u64 = 0;
let mut connects: i64 = 0;
let mut disconnects: i64 = 0;
while receiver.changed().await.is_ok() {
let stats = receiver.borrow();
for broker in stats.brokers.values() {
outbuf_cnt += broker.outbuf_cnt;
outbuf_msg_cnt += broker.outbuf_msg_cnt;
waitresp_cnt += broker.waitresp_cnt;
waitresp_msg_cnt += broker.waitresp_msg_cnt;
txerrs += broker.txerrs;
txretries += broker.txretries;
req_timeouts += broker.req_timeouts;
connects += broker.connects.unwrap_or(0);
disconnects += broker.disconnects.unwrap_or(0);
}
metrics.rdkafka_msg_cnt.set(stats.msg_cnt);
metrics.rdkafka_msg_size.set(stats.msg_size);
metrics.rdkafka_txmsgs.set(stats.txmsgs);
metrics.rdkafka_txmsg_bytes.set(stats.txmsg_bytes);
metrics.rdkafka_tx.set(stats.tx);
metrics.rdkafka_tx_bytes.set(stats.tx_bytes);
metrics.rdkafka_outbuf_cnt.set(outbuf_cnt);
metrics.rdkafka_outbuf_msg_cnt.set(outbuf_msg_cnt);
metrics.rdkafka_waitresp_cnt.set(waitresp_cnt);
metrics.rdkafka_waitresp_msg_cnt.set(waitresp_msg_cnt);
metrics.rdkafka_txerrs.set(txerrs);
metrics.rdkafka_txretries.set(txretries);
metrics.rdkafka_req_timeouts.set(req_timeouts);
metrics.rdkafka_connects.set(connects);
metrics.rdkafka_disconnects.set(disconnects);
}
}
/// A message to produce to Kafka.
#[derive(Debug, Clone, Serialize, Deserialize)]
struct KafkaMessage {
/// A hash of the key that can be used for partitioning.
hash: u64,
/// The message key.
key: Option<Vec<u8>>,
/// The message value.
value: Option<Vec<u8>>,
/// Message headers.
headers: Vec<KafkaHeader>,
}
/// A header to attach to a Kafka message.
#[derive(Debug, Clone, Serialize, Deserialize)]
struct KafkaHeader {
/// The header key.
key: String,
/// The header value.
value: Option<Vec<u8>>,
}
/// Sinks a collection of encoded rows to Kafka.
///
/// This operator exchanges all updates to a single worker by hashing on the given sink `id`.
///
/// Updates are sent in ascending timestamp order.
fn sink_collection<G: Scope<Timestamp = Timestamp>>(
name: String,
input: &Collection<G, KafkaMessage, Diff>,
sink_id: GlobalId,
connection: KafkaSinkConnection,
partition_strategy: SinkPartitionStrategy,
storage_configuration: StorageConfiguration,
sink: &StorageSinkDesc<MetadataFilled, Timestamp>,
metrics: KafkaSinkMetrics,
statistics: SinkStatistics,
write_frontier: Rc<RefCell<Antichain<Timestamp>>>,
) -> (Stream<G, HealthStatusMessage>, PressOnDropButton) {
let scope = input.scope();
let mut builder = AsyncOperatorBuilder::new(name.clone(), input.inner.scope());
// We want exactly one worker to send all the data to the sink topic.
let hashed_id = sink_id.hashed();
let is_active_worker = usize::cast_from(hashed_id) % scope.peers() == scope.index();
let buffer_min_capacity =
KAFKA_BUFFERED_EVENT_RESIZE_THRESHOLD_ELEMENTS.handle(storage_configuration.config_set());
let mut input = builder.new_disconnected_input(&input.inner, Exchange::new(move |_| hashed_id));
let as_of = sink.as_of.clone();
let sink_version = sink.version;
let (button, errors) = builder.build_fallible(move |_caps| {
Box::pin(async move {
if !is_active_worker {
write_frontier.borrow_mut().clear();
return Ok(());
}
fail::fail_point!("kafka_sink_creation_error", |_| Err(
ContextCreationError::Other(anyhow::anyhow!("synthetic error"))
));
let metrics = Arc::new(metrics);
let (mut producer, resume_upper) = TransactionalProducer::new(
sink_id,
&connection,
partition_strategy,
&storage_configuration,
Arc::clone(&metrics),
statistics,
sink_version,
)
.await?;
// The input has overcompacted if
let overcompacted =
// ..we have made some progress in the past
*resume_upper != [Timestamp::minimum()] &&
// ..but the since frontier is now beyond that
!PartialOrder::less_equal(&as_of, &resume_upper);
if overcompacted {
let err = format!(
"{name}: input compacted past resume upper: as_of {}, resume_upper: {}",
as_of.pretty(),
resume_upper.pretty()
);
// This would normally be an assertion but because it can happen after a
// Materialize backup/restore we log an error so that it appears on Sentry but
// leaves the rest of the objects in the cluster unaffected.
error!("{err}");
return Err(anyhow!("{err}").into());
}
info!(
"{name}: as_of: {}, resume upper: {}",
as_of.pretty(),
resume_upper.pretty()
);
// The section below relies on TotalOrder for correctness so we'll work with timestamps
// directly to make sure this doesn't compile if someone attempts to make this operator
// generic over partial orders in the future.
let Some(mut upper) = resume_upper.clone().into_option() else {
return Ok(());
};
let mut deferred_updates = vec![];
let mut extra_updates = vec![];
// We must wait until we have data to commit before starting a transaction because
// Kafka doesn't have a heartbeating mechanism to keep a transaction open indefinitely.
// This flag tracks whether we have started the transaction.
let mut transaction_begun = false;
while let Some(event) = input.next().await {
match event {
Event::Data(_cap, batch) => {
for (message, time, diff) in batch {
// We want to publish updates in time order and we know that we have
// already committed all times not beyond `upper`. Therefore, if this
// update happens *exactly* at upper then it is the minimum pending
// time and so emitting it now will not violate the timestamp publish
// order. This optimization is load bearing because it is the mechanism
// by which we incrementally stream the initial snapshot out to Kafka
// instead of buffering it all in memory first. This argument doesn't
// hold for partially ordered time because many different timestamps
// can be *exactly* at upper but we can't know ahead of time which one
// will be advanced in the next progress message.
match upper.cmp(&time) {
Ordering::Less => deferred_updates.push((message, time, diff)),
Ordering::Equal => {
if !transaction_begun {
producer.begin_transaction().await?;
transaction_begun = true;
}
producer.send(&message, time, diff)?;
}
Ordering::Greater => continue,
}
}
}
Event::Progress(progress) => {
// Ignore progress updates before our resumption frontier
if !PartialOrder::less_equal(&resume_upper, &progress) {
continue;
}
// Also ignore progress updates until we are past the as_of frontier. This
// is to avoid the following pathological scenario:
// 1. Sink gets instantiated with an as_of = {10}, resume_upper = {0}.
// `progress` initially jumps at {10}, then the snapshot appears at time
// 10.
// 2. `progress` would normally advance to say {11} and we would commit the
// snapshot but clusterd crashes instead.
// 3. A new cluster restarts the sink with an earlier as_of, say {5}. This
// is valid, the earlier as_of has strictly more information. The
// snapshot now appears at time 5.
//
// If we were to commit an empty transaction in step 1 and advanced the
// resume_upper to {10} then in step 3 we would ignore the snapshot that
// now appears at 5 completely. So it is important to only start committing
// transactions after we're strictly beyond the as_of.
// TODO(petrosagg): is this logic an indication of us holding something
// wrong elsewhere? Investigate.
// Note: !PartialOrder::less_than(as_of, progress) would not be equivalent
// nor correct for partially ordered times.
if !as_of.iter().all(|t| !progress.less_equal(t)) {
continue;
}
if !transaction_begun {
producer.begin_transaction().await?;
}
// N.B. Shrinking the Vec here is important because when starting the Sink
// we might buffer a ton of updates into these collections, e.g. if someone
// deleted the progress topic and the resume upper is 0, and we don't want
// to keep around a massively oversized VEc.
deferred_updates.shrink_to(buffer_min_capacity.get());
extra_updates.extend(
deferred_updates
.drain_filter_swapping(|(_, time, _)| !progress.less_equal(time)),
);
extra_updates.sort_unstable_by(|a, b| a.1.cmp(&b.1));
// N.B. See the comment above.
extra_updates.shrink_to(buffer_min_capacity.get());
for (message, time, diff) in extra_updates.drain(..) {
producer.send(&message, time, diff)?;
}
info!("{name}: committing transaction for {}", progress.pretty());
producer.commit_transaction(progress.clone()).await?;
transaction_begun = false;
write_frontier.borrow_mut().clone_from(&progress);
match progress.into_option() {
Some(new_upper) => upper = new_upper,
None => break,
}
}
}
}
Ok(())
})
});
let statuses = errors.map(|error: Rc<ContextCreationError>| {
let hint = match *error {
ContextCreationError::KafkaError(KafkaError::Transaction(ref e)) => {
if e.is_retriable() && e.code() == RDKafkaErrorCode::OperationTimedOut {
let hint = "If you're running a single Kafka broker, ensure that the configs \
transaction.state.log.replication.factor, transaction.state.log.min.isr, \
and offsets.topic.replication.factor are set to 1 on the broker";
Some(hint.to_owned())
} else {
None
}
}
_ => None,
};
HealthStatusMessage {
index: 0,
update: HealthStatusUpdate::halting(format!("{}", error.display_with_causes()), hint),
namespace: if matches!(*error, ContextCreationError::Ssh(_)) {
StatusNamespace::Ssh
} else {
StatusNamespace::Kafka
},
}
});
(statuses, button.press_on_drop())
}
/// Determines the latest progress record from the specified topic for the given
/// progress key.
///
/// IMPORTANT: to achieve exactly once guarantees, the producer that will resume
/// production at the returned timestamp *must* have called `init_transactions`
/// prior to calling this method.
async fn determine_sink_progress(
sink_id: GlobalId,
connection: &KafkaSinkConnection,
storage_configuration: &StorageConfiguration,
metrics: Arc<KafkaSinkMetrics>,
) -> Result<Option<ProgressRecord>, ContextCreationError> {
// ****************************** WARNING ******************************
// Be VERY careful when editing the code in this function. It is very easy
// to accidentally introduce a correctness or liveness bug when refactoring
// this code.
// ****************************** WARNING ******************************
let TimeoutConfig {
fetch_metadata_timeout,
progress_record_fetch_timeout,
..
} = storage_configuration.parameters.kafka_timeout_config;
let client_id = connection.client_id(
storage_configuration.config_set(),
&storage_configuration.connection_context,
sink_id,
);
let group_id = connection.progress_group_id(&storage_configuration.connection_context, sink_id);
let progress_topic = connection
.progress_topic(&storage_configuration.connection_context)
.into_owned();
let progress_topic_options = &connection.connection.progress_topic_options;
let progress_key = ProgressKey::new(sink_id);
let common_options = btreemap! {
// Consumer group ID, which may have been overridden by the user. librdkafka requires this,
// even though we'd prefer to disable the consumer group protocol entirely.
"group.id" => group_id,
// Allow Kafka monitoring tools to identify this consumer.
"client.id" => client_id,
"enable.auto.commit" => "false".into(),
"auto.offset.reset" => "earliest".into(),
// The fetch loop below needs EOF notifications to reliably detect that we have reached the
// high watermark.
"enable.partition.eof" => "true".into(),
};
// Construct two cliens in read committed and read uncommitted isolations respectively. See
// comment below for an explanation on why we need it.
let progress_client_read_committed: BaseConsumer<_> = {
let mut opts = common_options.clone();
opts.insert("isolation.level", "read_committed".into());
let ctx = MzClientContext::default();
connection
.connection
.create_with_context(storage_configuration, ctx, &opts, InTask::Yes)
.await?
};
let progress_client_read_uncommitted: BaseConsumer<_> = {
let mut opts = common_options;
opts.insert("isolation.level", "read_uncommitted".into());
let ctx = MzClientContext::default();
connection
.connection
.create_with_context(storage_configuration, ctx, &opts, InTask::Yes)
.await?
};
let ctx = Arc::clone(progress_client_read_committed.client().context());
// Ensure the progress topic exists.
mz_storage_client::sink::ensure_kafka_topic(
connection,
storage_configuration,
&progress_topic,
progress_topic_options,
)
.await
.add_context("error registering kafka progress topic for sink")?;
// We are about to spawn a blocking task that cannot be aborted by simply calling .abort() on
// its handle but we must be able to cancel it prompty so as to not leave long running
// operations around when interest to this task is lost. To accomplish this we create a shared
// token of which a weak reference is given to the task and a strong reference is held by the
// parent task. The task periodically checks if its weak reference is still valid before
// continuing its work.
let parent_token = Arc::new(());
let child_token = Arc::downgrade(&parent_token);
let task_name = format!("get_latest_ts:{sink_id}");
let result = task::spawn_blocking(|| task_name, move || {
let progress_topic = progress_topic.as_ref();
// Ensure the progress topic has exactly one partition. Kafka only
// guarantees ordering within a single partition, and we need a strict
// order on the progress messages we read and write.
let partitions = match mz_kafka_util::client::get_partitions(
progress_client_read_committed.client(),
progress_topic,
fetch_metadata_timeout,
) {
Ok(partitions) => partitions,
Err(GetPartitionsError::TopicDoesNotExist) => {
// The progress topic doesn't exist, which indicates there is
// no committed timestamp.
return Ok(None);
}
e => e.with_context(|| {
format!(
"Unable to fetch metadata about progress topic {}",
progress_topic
)
})?,
};
if partitions.len() != 1 {
bail!(
"Progress topic {} should contain a single partition, but instead contains {} partitions",
progress_topic, partitions.len(),
);
}
let partition = partitions.into_element();
// We scan from the beginning and see if we can find a progress record. We have
// to do it like this because Kafka Control Batches mess with offsets. We
// therefore cannot simply take the last offset from the back and expect a
// progress message there. With a transactional producer, the OffsetTail(1) will
// not point to an progress message but a control message. With aborted
// transactions, there might even be a lot of garbage at the end of the
// topic or in between.
metrics.consumed_progress_records.set(0);
// First, determine the current high water mark for the progress topic.
// This is the position our `progress_client` consumer *must* reach
// before we can conclude that we've seen the latest progress record for
// the specified `progress_key`. A safety argument:
//
// * Our caller has initialized transactions before calling this
// method, which prevents the prior incarnation of this sink from
// committing any further progress records.
//
// * We use `read_uncommitted` isolation to ensure that we fetch the
// true high water mark for the topic, even if there are pending
// transactions in the topic. If we used the `read_committed`
// isolation level, we'd instead get the "last stable offset" (LSO),
// which is the offset of the first message in an open transaction,
// which might not include the last progress message committed for
// this sink! (While the caller of this function has fenced out
// older producers for this sink, *other* sinks writing using the
// same progress topic might have long-running transactions that
// hold back the LSO.)
//
// * If another sink spins up and fences out the producer for this
// incarnation of the sink, we may not see the latest progress
// record... but since the producer has been fenced out, it will be
// unable to act on our stale information.
//
let (lo, hi) = progress_client_read_uncommitted
.fetch_watermarks(progress_topic, partition, fetch_metadata_timeout)
.map_err(|e| {
anyhow!(
"Failed to fetch metadata while reading from progress topic: {}",
e
)
})?;
// Seek to the beginning of the progress topic.
let mut tps = TopicPartitionList::new();
tps.add_partition(progress_topic, partition);
tps.set_partition_offset(progress_topic, partition, Offset::Beginning)?;
progress_client_read_committed
.assign(&tps)
.with_context(|| {
format!(
"Error seeking in progress topic {}:{}",
progress_topic, partition
)
})?;
// Helper to get the progress consumer's current position.
let get_position = || {
if child_token.strong_count() == 0 {
bail!("operation cancelled");
}
let position = progress_client_read_committed
.position()?
.find_partition(progress_topic, partition)
.ok_or_else(|| {
anyhow!(
"No position info found for progress topic {}",
progress_topic
)
})?
.offset();
let position = match position {
Offset::Offset(position) => position,
// An invalid offset indicates the consumer has not yet read a
// message. Since we assigned the consumer to the beginning of
// the topic, it's safe to return the low water mark here, which
// indicates the position before the first possible message.
//
// Note that it's important to return the low water mark and not
// the minimum possible offset (i.e., zero) in order to break
// out of the loop if the topic is empty but the low water mark
// is greater than zero.
Offset::Invalid => lo,
_ => bail!(
"Consumer::position returned offset of wrong type: {:?}",
position
),
};
// Record the outstanding number of progress records that remain to be processed
let outstanding = u64::try_from(std::cmp::max(0, hi - position)).unwrap();
metrics.outstanding_progress_records.set(outstanding);
Ok(position)
};
info!("fetching latest progress record for {progress_key}, lo/hi: {lo}/{hi}");
// Read messages until the consumer is positioned at or beyond the high
// water mark.
//
// We use `read_committed` isolation to ensure we don't see progress
// records for transactions that did not commit. This means we have to
// wait for the LSO to progress to the high water mark `hi`, which means
// waiting for any open transactions for other sinks using the same
// progress topic to complete. We set a short transaction timeout (10s)
// to ensure we never need to wait more than 10s.
//
// Note that the stall time on the progress topic is not a function of
// transaction size. We've designed our transactions so that the
// progress record is always written last, after all the data has been
// written, and so the window of time in which the progress topic has an
// open transaction is quite small. The only vulnerability is if another
// sink using the same progress topic crashes in that small window
// between writing the progress record and committing the transaction,
// in which case we have to wait out the transaction timeout.
//
// Important invariant: we only exit this loop successfully (i.e., not
// returning an error) if we have positive proof of a position at or
// beyond the high water mark. To make this invariant easy to check, do
// not use `break` in the body of the loop.
let mut last_progress: Option<ProgressRecord> = None;
loop {
let current_position = get_position()?;
if current_position >= hi {
// consumer is at or beyond the high water mark and has read enough messages
break;
}
let message = match progress_client_read_committed.poll(progress_record_fetch_timeout) {
Some(Ok(message)) => message,
Some(Err(KafkaError::PartitionEOF(_))) => {
// No message, but the consumer's position may have advanced
// past a transaction control message that positions us at
// or beyond the high water mark. Go around the loop again
// to check.
continue;
}
Some(Err(e)) => bail!("failed to fetch progress message {e}"),
None => {
bail!(
"timed out while waiting to reach high water mark of non-empty \
topic {progress_topic}:{partition}, lo/hi: {lo}/{hi}, current position: {current_position}"
);
}
};
if message.key() != Some(progress_key.to_bytes()) {
// This is a progress message for a different sink.
continue;
}
metrics.consumed_progress_records.inc();
let Some(payload) = message.payload() else {
continue
};
let progress = parse_progress_record(payload)?;
match last_progress {
Some(last_progress) if !PartialOrder::less_equal(&last_progress.frontier, &progress.frontier) => {
bail!(
"upper regressed in topic {progress_topic}:{partition} from {:?} to {:?}",
&last_progress.frontier,
&progress.frontier,
);
}
_ => last_progress = Some(progress),
}
}
// If we get here, we are assured that we've read all messages up to
// the high water mark, and therefore `last_timestamp` contains the
// most recent timestamp for the sink under consideration.
Ok(last_progress)
}).await.unwrap().check_ssh_status(&ctx);
// Express interest to the computation until after we've received its result
drop(parent_token);
result
}
/// This is the legacy struct that used to be emitted as part of a transactional produce and
/// contains the largest timestamp within the batch committed. Since it is just a timestamp it
/// cannot encode the fact that a sink has finished and deviates from upper frontier semantics.
/// Materialize no longer produces this record but it's possible that we encounter this in topics
/// written by older versions. In those cases we convert it into upper semantics by stepping the
/// timestamp forward.
#[derive(Debug, PartialEq, Serialize, Deserialize)]
pub struct LegacyProgressRecord {
// Double Option to tell apart an omitted field from one set to null explicitly
// https://github.com/serde-rs/serde/issues/984
#[serde(default, deserialize_with = "deserialize_some")]
pub timestamp: Option<Option<Timestamp>>,
}
// Any value that is present is considered Some value, including null.
fn deserialize_some<'de, T, D>(deserializer: D) -> Result<Option<T>, D::Error>
where
T: Deserialize<'de>,
D: Deserializer<'de>,
{
Deserialize::deserialize(deserializer).map(Some)
}
/// This struct is emitted as part of a transactional produce, and contains the upper frontier of
/// the batch committed. It is used to recover the frontier a sink needs to resume at.
#[derive(Debug, PartialEq, Serialize, Deserialize)]
pub struct ProgressRecord {
#[serde(
deserialize_with = "deserialize_frontier",
serialize_with = "serialize_frontier"
)]
pub frontier: Antichain<Timestamp>,
#[serde(default)]
pub version: u64,
}
fn serialize_frontier<S>(frontier: &Antichain<Timestamp>, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
Serialize::serialize(frontier.elements(), serializer)
}
fn deserialize_frontier<'de, D>(deserializer: D) -> Result<Antichain<Timestamp>, D::Error>
where
D: Deserializer<'de>,
{
let times: Vec<Timestamp> = Deserialize::deserialize(deserializer)?;
Ok(Antichain::from(times))
}
fn parse_progress_record(payload: &[u8]) -> Result<ProgressRecord, anyhow::Error> {
Ok(match serde_json::from_slice::<ProgressRecord>(payload) {
Ok(progress) => progress,
// If we fail to deserialize we might be reading a legacy progress record
Err(_) => match serde_json::from_slice::<LegacyProgressRecord>(payload) {
Ok(LegacyProgressRecord {
timestamp: Some(Some(time)),
}) => ProgressRecord {
frontier: Antichain::from_elem(time.step_forward()),
version: 0,
},
Ok(LegacyProgressRecord {
timestamp: Some(None),
}) => ProgressRecord {
frontier: Antichain::new(),
version: 0,
},
_ => match std::str::from_utf8(payload) {
Ok(payload) => bail!("invalid progress record: {payload}"),
Err(_) => bail!("invalid progress record bytes: {payload:?}"),
},
},
})
}
/// Fetches the partition count for the identified topic.
async fn fetch_partition_count(
producer: &ThreadedProducer<TunnelingClientContext<MzClientContext>>,
sink_id: GlobalId,
topic_name: &str,
) -> Result<u64, anyhow::Error> {
let meta = task::spawn_blocking(|| format!("kafka_sink_fetch_partition_count:{sink_id}"), {
let producer = producer.clone();
move || {
producer
.client()
.fetch_metadata(None, DEFAULT_FETCH_METADATA_TIMEOUT)
}
})
.await
.expect("spawning blocking task cannot fail")
.check_ssh_status(producer.context())?;
match meta.topics().iter().find(|t| t.name() == topic_name) {
Some(topic) => {
let partition_count = u64::cast_from(topic.partitions().len());
if partition_count == 0 {
bail!("topic {topic_name} has an impossible partition count of zero");
}
Ok(partition_count)
}
None => bail!("topic {topic_name} does not exist"),
}
}
/// Fetches the partition count for the identified topic at the specified
/// interval.
///
/// When an updated partition count is discovered, invokes
/// `update_partition_count` with the new partition count.
async fn fetch_partition_count_loop<F>(
producer: ThreadedProducer<TunnelingClientContext<MzClientContext>>,
sink_id: GlobalId,
topic_name: String,
interval: Duration,
update_partition_count: Arc<F>,
) where
F: Fn(u64),
{
let mut interval = time::interval(interval);
interval.set_missed_tick_behavior(MissedTickBehavior::Delay);
loop {
interval.tick().await;
match fetch_partition_count(&producer, sink_id, &topic_name).await {
Ok(pc) => update_partition_count(pc),
Err(e) => {
warn!(%sink_id, "failed updating partition count: {e}");
continue;
}
};
}
}
/// Encodes a stream of `(Option<Row>, Option<Row>)` updates using the specified encoder.
///
/// Input [`Row`] updates must me compatible with the given implementor of [`Encode`].
fn encode_collection<G: Scope>(
name: String,
input: &Collection<G, (Option<Row>, DiffPair<Row>), Diff>,
envelope: SinkEnvelope,
connection: KafkaSinkConnection,
storage_configuration: StorageConfiguration,
) -> (
Collection<G, KafkaMessage, Diff>,
Stream<G, HealthStatusMessage>,
PressOnDropButton,
) {
let mut builder = AsyncOperatorBuilder::new(name, input.inner.scope());
let (output, stream) = builder.new_output();
let mut input = builder.new_input_for(&input.inner, Pipeline, &output);
let (button, errors) = builder.build_fallible(move |caps| {
Box::pin(async move {
let [capset]: &mut [_; 1] = caps.try_into().unwrap();
let key_desc = connection
.key_desc_and_indices
.as_ref()
.map(|(desc, _indices)| desc.clone());
let value_desc = connection.value_desc;
let key_encoder: Option<Box<dyn Encode>> =
match (key_desc, connection.format.key_format) {
(Some(desc), Some(KafkaSinkFormatType::Bytes)) => {
Some(Box::new(BinaryEncoder::new(desc, false)))
}
(Some(desc), Some(KafkaSinkFormatType::Text)) => {
Some(Box::new(TextEncoder::new(desc, false)))
}
(Some(desc), Some(KafkaSinkFormatType::Json)) => {
Some(Box::new(JsonEncoder::new(desc, false)))
}
(Some(desc), Some(KafkaSinkFormatType::Avro {
schema,
compatibility_level,
csr_connection,
})) => {
// Ensure that schemas are registered with the schema registry.
//
// Note that where this lies in the rendering cycle means that we will publish the
// schemas each time the sink is rendered.
let ccsr = csr_connection
.connect(&storage_configuration, InTask::Yes)
.await?;
let schema_id = mz_storage_client::sink::publish_kafka_schema(
ccsr,
format!("{}-key", connection.topic),
schema.clone(),
mz_ccsr::SchemaType::Avro,
compatibility_level,
)
.await
.context("error publishing kafka schemas for sink")?;
Some(Box::new(AvroEncoder::new(desc, false, &schema, schema_id)))
}
(None, None) => None,
(desc, format) => {
return Err(anyhow!(
"key_desc and key_format must be both set or both unset, but key_desc: {:?}, key_format: {:?}",
desc,
format
))
}
};
// whether to apply the debezium envelope to the value encoding
let debezium = matches!(envelope, SinkEnvelope::Debezium);
let value_encoder: Box<dyn Encode> = match connection.format.value_format {
KafkaSinkFormatType::Bytes => Box::new(BinaryEncoder::new(value_desc, debezium)),
KafkaSinkFormatType::Text => Box::new(TextEncoder::new(value_desc, debezium)),
KafkaSinkFormatType::Json => Box::new(JsonEncoder::new(value_desc, debezium)),
KafkaSinkFormatType::Avro {
schema,
compatibility_level,
csr_connection,
} => {
// Ensure that schemas are registered with the schema registry.
//
// Note that where this lies in the rendering cycle means that we will publish the
// schemas each time the sink is rendered.
let ccsr = csr_connection
.connect(&storage_configuration, InTask::Yes)
.await?;
let schema_id = mz_storage_client::sink::publish_kafka_schema(
ccsr,
format!("{}-value", connection.topic),
schema.clone(),
mz_ccsr::SchemaType::Avro,
compatibility_level,
)
.await
.context("error publishing kafka schemas for sink")?;
Box::new(AvroEncoder::new(value_desc, debezium, &schema, schema_id))
}
};
// !IMPORTANT!
// Correctness of this operator relies on no fallible operations happening after this
// point. This is a temporary workaround of build_fallible's bad interaction of owned
// capabilities and errors.
// TODO(petrosagg): Make the fallible async operator safe
*capset = CapabilitySet::new();
let mut row_buf = Row::default();
let mut datums = DatumVec::new();
while let Some(event) = input.next().await {
if let Event::Data(cap, rows) = event {
for ((key, value), time, diff) in rows {
let mut hash = None;
let mut headers = vec![];
if connection.headers_index.is_some() || connection.partition_by.is_some() {
// Header values and partition by values are derived from the row that
// produces an event. But it is ambiguous whether to use the `before` or
// `after` from the event. The rule applied here is simple: use `after`
// if it exists (insertions and updates), otherwise fall back to `before`
// (deletions).
//
// It is up to the SQL planner to ensure this produces sensible results.
// (When using the upsert envelope and both `before` and `after` are
// present, it's always unambiguous to use `after` because that's all
// that will be present in the Kafka message; when using the Debezium
// envelope, it's okay to refer to columns in the key because those
// are guaranteed to be the same in both `before` and `after`.)
let row = value
.after
.as_ref()
.or(value.before.as_ref())
.expect("one of before or after must be set");
let row = datums.borrow_with(row);
if let Some(i) = connection.headers_index {
headers = encode_headers(row[i]);
}
if let Some(partition_by) = &connection.partition_by {
hash = Some(evaluate_partition_by(partition_by, &row));
}
}
let (key, hash) = match key {
Some(key) => {
let key_encoder = key_encoder.as_ref().expect("key present");
let key = key_encoder.encode_unchecked(key);
let hash = hash.unwrap_or_else(|| key_encoder.hash(&key));
(Some(key), hash)
}
None => (None, hash.unwrap_or(0))
};
let value = match envelope {
SinkEnvelope::Upsert => value.after,
SinkEnvelope::Debezium => {
dbz_format(&mut row_buf.packer(), value);
Some(row_buf.clone())
}
};
let value = value.map(|value| value_encoder.encode_unchecked(value));
let message = KafkaMessage {
hash,
key,
value,
headers,
};
output.give(&cap, (message, time, diff));
}
}
}
Ok::<(), anyhow::Error>(())
})
});
let statuses = errors.map(|error| HealthStatusMessage {
index: 0,
update: HealthStatusUpdate::halting(format!("{}", error.display_with_causes()), None),
namespace: StatusNamespace::Kafka,
});
(stream.as_collection(), statuses, button.press_on_drop())
}
fn encode_headers(datum: Datum) -> Vec<KafkaHeader> {
let mut out = vec![];
if datum.is_null() {
return out;
}
for (key, value) in datum.unwrap_map().iter() {
out.push(KafkaHeader {
key: key.into(),
value: match value {
Datum::Null => None,
Datum::String(s) => Some(s.as_bytes().to_vec()),
Datum::Bytes(b) => Some(b.to_vec()),
_ => panic!("encode_headers called with unexpected header value {value:?}"),
},
})
}
out
}
/// Evaluates a partition by expression on the given row, returning the hash
/// value to use for partition assignment.
///
/// The provided expression must have type `Int32`, `Int64`, `UInt32`, or
/// `UInt64`. If the expression produces an error when evaluated, or if the
/// expression is of a signed integer type and produces a negative value, this
/// function returns 0.
fn evaluate_partition_by(partition_by: &MirScalarExpr, row: &[Datum]) -> u64 {
// NOTE(benesch): The way this function converts errors and invalid values
// to 0 is somewhat surpising. Ideally, we would put the sink in a
// permanently errored state if the partition by expression produces an
// error or invalid value. But we don't presently have a way for sinks to
// report errors (see materialize#17688), so the current behavior was determined to be
// the best available option. The behavior is clearly documented in the
// user-facing `CREATE SINK` docs.
let temp_storage = RowArena::new();
match partition_by.eval(row, &temp_storage) {
Ok(hash) => match hash {
Datum::Int32(i) => i.try_into().unwrap_or(0),
Datum::Int64(i) => i.try_into().unwrap_or(0),
Datum::UInt32(u) => u64::from(u),
Datum::UInt64(u) => u,
_ => unreachable!(),
},
Err(_) => 0,
}
}
#[cfg(test)]
mod test {
use mz_ore::assert_err;
use super::*;
#[mz_ore::test]
fn progress_record_migration() {
assert_err!(parse_progress_record(b"{}"));
assert_eq!(
parse_progress_record(b"{\"timestamp\":1}").unwrap(),
ProgressRecord {
frontier: Antichain::from_elem(2.into()),
version: 0,
}
);
assert_eq!(
parse_progress_record(b"{\"timestamp\":null}").unwrap(),
ProgressRecord {
frontier: Antichain::new(),
version: 0,
}
);
assert_eq!(
parse_progress_record(b"{\"frontier\":[1]}").unwrap(),
ProgressRecord {
frontier: Antichain::from_elem(1.into()),
version: 0,
}
);
assert_eq!(
parse_progress_record(b"{\"frontier\":[]}").unwrap(),
ProgressRecord {
frontier: Antichain::new(),
version: 0,
}
);
assert_eq!(
parse_progress_record(b"{\"frontier\":[], \"version\": 42}").unwrap(),
ProgressRecord {
frontier: Antichain::new(),
version: 42,
}
);
assert_err!(parse_progress_record(b"{\"frontier\":null}"));
}
}