1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945
// 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.
use std::cell::RefCell;
use std::cmp::Reverse;
use std::convert::AsRef;
use std::fmt::Debug;
use std::hash::{Hash, Hasher};
use std::sync::Arc;
use differential_dataflow::consolidation;
use differential_dataflow::hashable::Hashable;
use differential_dataflow::{AsCollection, Collection};
use futures::future::FutureExt;
use indexmap::map::Entry;
use itertools::Itertools;
use mz_ore::cast::CastFrom;
use mz_ore::error::ErrorExt;
use mz_repr::{Datum, DatumVec, Diff, Row};
use mz_storage_operators::metrics::BackpressureMetrics;
use mz_storage_types::configuration::StorageConfiguration;
use mz_storage_types::dyncfgs;
use mz_storage_types::errors::{DataflowError, EnvelopeError, UpsertError};
use mz_storage_types::sources::envelope::UpsertEnvelope;
use mz_timely_util::builder_async::{
AsyncOutputHandle, Event as AsyncEvent, OperatorBuilder as AsyncOperatorBuilder,
PressOnDropButton,
};
use serde::{Deserialize, Serialize};
use sha2::{Digest, Sha256};
use timely::dataflow::channels::pact::Exchange;
use timely::dataflow::channels::pushers::Tee;
use timely::dataflow::operators::Capability;
use timely::dataflow::{Scope, ScopeParent, Stream};
use timely::order::{PartialOrder, TotalOrder};
use timely::progress::{Antichain, Timestamp};
use crate::healthcheck::HealthStatusUpdate;
use crate::metrics::upsert::UpsertMetrics;
use crate::render::sources::OutputIndex;
use crate::render::upsert::autospill::{AutoSpillBackend, RocksDBParams};
use crate::render::upsert::memory::InMemoryHashMap;
use crate::render::upsert::types::{
upsert_bincode_opts, StateValue, UpsertState, UpsertStateBackend, Value,
};
use crate::storage_state::StorageInstanceContext;
mod autospill;
mod memory;
mod rocksdb;
mod types;
pub type UpsertValue = Result<Row, UpsertError>;
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
pub struct UpsertKey([u8; 32]);
impl AsRef<[u8]> for UpsertKey {
#[inline(always)]
// Note we do 1 `multi_get` and 1 `multi_put` while processing a _batch of updates_. Within the
// batch, we effectively consolidate each key, before persisting that consolidated value.
// Easy!!
fn as_ref(&self) -> &[u8] {
&self.0
}
}
thread_local! {
/// A thread-local datum cache used to calculate hashes
pub static KEY_DATUMS: RefCell<DatumVec> = RefCell::new(DatumVec::new());
}
/// The hash function used to map upsert keys. It is important that this hash is a cryptographic
/// hash so that there is no risk of collisions. Collisions on SHA256 have a probability of 2^128
/// which is many orders of magnitude smaller than many other events that we don't even think about
/// (e.g bit flips). In short, we can safely assume that sha256(a) == sha256(b) iff a == b.
type KeyHash = Sha256;
impl UpsertKey {
pub fn from_key(key: Result<&Row, &UpsertError>) -> Self {
Self::from_iter(key.map(|r| r.iter()))
}
pub fn from_value(value: Result<&Row, &UpsertError>, mut key_indices: &[usize]) -> Self {
Self::from_iter(value.map(|value| {
value.iter().enumerate().flat_map(move |(idx, datum)| {
let key_idx = key_indices.get(0)?;
if idx == *key_idx {
key_indices = &key_indices[1..];
Some(datum)
} else {
None
}
})
}))
}
pub fn from_iter<'a, 'b>(
key: Result<impl Iterator<Item = Datum<'a>> + 'b, &UpsertError>,
) -> Self {
KEY_DATUMS.with(|key_datums| {
let mut key_datums = key_datums.borrow_mut();
// Borrowing the DatumVec gives us a temporary buffer to store datums in that will be
// automatically cleared on Drop. See the DatumVec docs for more details.
let mut key_datums = key_datums.borrow();
let key: Result<&[Datum], Datum> = match key {
Ok(key) => {
for datum in key {
key_datums.push(datum);
}
Ok(&*key_datums)
}
Err(UpsertError::Value(err)) => {
key_datums.extend(err.for_key.iter());
Ok(&*key_datums)
}
Err(UpsertError::KeyDecode(err)) => Err(Datum::Bytes(&err.raw)),
Err(UpsertError::NullKey(_)) => Err(Datum::Null),
};
let mut hasher = DigestHasher(KeyHash::new());
key.hash(&mut hasher);
Self(hasher.0.finalize().into())
})
}
}
struct DigestHasher<H: Digest>(H);
impl<H: Digest> Hasher for DigestHasher<H> {
fn write(&mut self, bytes: &[u8]) {
self.0.update(bytes);
}
fn finish(&self) -> u64 {
panic!("digest wrapper used to produce a hash");
}
}
use std::convert::Infallible;
use timely::dataflow::channels::pact::Pipeline;
use self::types::ValueMetadata;
/// This leaf operator drops `token` after the input reaches the `resume_upper`.
/// This is useful to take coordinated actions across all workers, after the `upsert`
/// operator has rehydrated.
pub fn rehydration_finished<G, T>(
scope: G,
source_config: &crate::source::RawSourceCreationConfig,
// A token that we can drop to signal we are finished rehydrating.
token: impl std::any::Any + 'static,
resume_upper: Antichain<T>,
input: &Stream<G, Infallible>,
) where
G: Scope<Timestamp = T>,
T: Timestamp,
{
let worker_id = source_config.worker_id;
let id = source_config.id;
let mut builder = AsyncOperatorBuilder::new(format!("rehydration_finished({id}"), scope);
let mut input = builder.new_disconnected_input(input, Pipeline);
builder.build(move |_capabilities| async move {
let mut input_upper = Antichain::from_elem(Timestamp::minimum());
// Ensure this operator finishes if the resume upper is `[0]`
while !PartialOrder::less_equal(&resume_upper, &input_upper) {
let Some(event) = input.next().await else {
break;
};
if let AsyncEvent::Progress(upper) = event {
input_upper = upper;
}
}
tracing::info!(
"timely-{worker_id} upsert source {id} has downgraded past the resume upper ({resume_upper:?}) across all workers",
);
drop(token);
});
}
/// Resumes an upsert computation at `resume_upper` given as inputs a collection of upsert commands
/// and the collection of the previous output of this operator.
/// Returns a tuple of
/// - A collection of the computed upsert operator and,
/// - A health update stream to propagate errors
pub(crate) fn upsert<G: Scope, FromTime>(
input: &Collection<G, (UpsertKey, Option<UpsertValue>, FromTime), Diff>,
upsert_envelope: UpsertEnvelope,
resume_upper: Antichain<G::Timestamp>,
previous: Collection<G, Result<Row, DataflowError>, Diff>,
previous_token: Option<Vec<PressOnDropButton>>,
source_config: crate::source::RawSourceCreationConfig,
instance_context: &StorageInstanceContext,
storage_configuration: &StorageConfiguration,
dataflow_paramters: &crate::internal_control::DataflowParameters,
backpressure_metrics: Option<BackpressureMetrics>,
) -> (
Collection<G, Result<Row, DataflowError>, Diff>,
Stream<G, (OutputIndex, HealthStatusUpdate)>,
PressOnDropButton,
)
where
G::Timestamp: TotalOrder,
FromTime: timely::ExchangeData + Ord,
{
let upsert_metrics = source_config.metrics.get_upsert_metrics(
source_config.id,
source_config.worker_id,
backpressure_metrics,
);
// If we are configured to delay raw sources till we rehydrate, we do so. Otherwise, skip
// this, to prevent unnecessary work.
let wait_for_input_resumption =
dyncfgs::DELAY_SOURCES_PAST_REHYDRATION.get(storage_configuration.config_set());
// Whether or not to partially drain the input buffer
// to prevent buffering of the _upstream_ snapshot.
let prevent_snapshot_buffering =
dyncfgs::STORAGE_UPSERT_PREVENT_SNAPSHOT_BUFFERING.get(storage_configuration.config_set());
// If the above is true, the number of timely batches to process at once.
let snapshot_buffering_max = dyncfgs::STORAGE_UPSERT_MAX_SNAPSHOT_BATCH_BUFFERING
.get(storage_configuration.config_set());
let upsert_config = UpsertConfig {
wait_for_input_resumption,
shrink_upsert_unused_buffers_by_ratio: storage_configuration
.parameters
.shrink_upsert_unused_buffers_by_ratio,
};
if let Some(scratch_directory) = instance_context.scratch_directory.as_ref() {
let tuning = dataflow_paramters.upsert_rocksdb_tuning_config.clone();
let allow_auto_spill = storage_configuration
.parameters
.upsert_auto_spill_config
.allow_spilling_to_disk;
let spill_threshold = storage_configuration
.parameters
.upsert_auto_spill_config
.spill_to_disk_threshold_bytes;
tracing::info!(
?tuning,
?storage_configuration.parameters.upsert_auto_spill_config,
"timely-{} rendering {} with rocksdb-backed upsert state",
source_config.worker_id,
source_config.id
);
let rocksdb_shared_metrics = Arc::clone(&upsert_metrics.rocksdb_shared);
let rocksdb_instance_metrics = Arc::clone(&upsert_metrics.rocksdb_instance_metrics);
let rocksdb_dir = scratch_directory
.join("storage")
.join("upsert")
.join(source_config.id.to_string())
.join(source_config.worker_id.to_string());
let legacy_rocksdb_dir = scratch_directory
.join(source_config.id.to_string())
.join(source_config.worker_id.to_string());
let env = instance_context.rocksdb_env.clone();
let rocksdb_in_use_metric = Arc::clone(&upsert_metrics.rocksdb_autospill_in_use);
if allow_auto_spill {
upsert_inner(
input,
upsert_envelope.key_indices,
resume_upper,
previous,
previous_token,
upsert_metrics,
source_config,
move || async move {
AutoSpillBackend::new(
RocksDBParams {
instance_path: rocksdb_dir,
legacy_instance_path: legacy_rocksdb_dir,
env,
tuning_config: tuning,
shared_metrics: rocksdb_shared_metrics,
instance_metrics: rocksdb_instance_metrics,
},
spill_threshold,
rocksdb_in_use_metric,
)
},
upsert_config,
prevent_snapshot_buffering,
snapshot_buffering_max,
)
} else {
upsert_inner(
input,
upsert_envelope.key_indices,
resume_upper,
previous,
previous_token,
upsert_metrics,
source_config,
move || async move {
rocksdb::RocksDB::new(
mz_rocksdb::RocksDBInstance::new(
&rocksdb_dir,
&legacy_rocksdb_dir,
mz_rocksdb::InstanceOptions::defaults_with_env(env),
tuning,
rocksdb_shared_metrics,
rocksdb_instance_metrics,
// For now, just use the same config as the one used for
// merging snapshots.
upsert_bincode_opts(),
)
.await
.unwrap(),
)
},
upsert_config,
prevent_snapshot_buffering,
snapshot_buffering_max,
)
}
} else {
tracing::info!(
"timely-{} rendering {} with memory-backed upsert state",
source_config.worker_id,
source_config.id
);
upsert_inner(
input,
upsert_envelope.key_indices,
resume_upper,
previous,
previous_token,
upsert_metrics,
source_config,
|| async { InMemoryHashMap::default() },
upsert_config,
prevent_snapshot_buffering,
snapshot_buffering_max,
)
}
}
/// Helper method for `upsert_inner` used to stage `data` updates
/// from the input timely edge.
fn stage_input<T, FromTime>(
stash: &mut Vec<(T, UpsertKey, Reverse<FromTime>, Option<UpsertValue>)>,
data: &mut Vec<((UpsertKey, Option<UpsertValue>, FromTime), T, Diff)>,
input_upper: &Antichain<T>,
resume_upper: &Antichain<T>,
storage_shrink_upsert_unused_buffers_by_ratio: usize,
) where
T: PartialOrder,
FromTime: Ord,
{
if PartialOrder::less_equal(input_upper, resume_upper) {
data.retain(|(_, ts, _)| resume_upper.less_equal(ts));
}
stash.extend(data.drain(..).map(|((key, value, order), time, diff)| {
assert!(diff > 0, "invalid upsert input");
(time, key, Reverse(order), value)
}));
if storage_shrink_upsert_unused_buffers_by_ratio > 0 {
let reduced_capacity = stash.capacity() / storage_shrink_upsert_unused_buffers_by_ratio;
if reduced_capacity > stash.len() {
stash.shrink_to(reduced_capacity);
}
}
}
/// The style of drain we are performing on the stash. `AtTime`-drains cannot
/// assume that all values have been seen, and must leave tombstones behind for deleted values.
#[derive(Debug)]
enum DrainStyle<'a, T> {
ToUpper(&'a Antichain<T>),
AtTime(T),
}
/// Helper method for `upsert_inner` used to stage `data` updates
/// from the input timely edge.
async fn drain_staged_input<S, G, T, FromTime, E>(
stash: &mut Vec<(T, UpsertKey, Reverse<FromTime>, Option<UpsertValue>)>,
commands_state: &mut indexmap::IndexMap<UpsertKey, types::UpsertValueAndSize<Option<FromTime>>>,
output_updates: &mut Vec<(Result<Row, UpsertError>, T, Diff)>,
multi_get_scratch: &mut Vec<UpsertKey>,
drain_style: DrainStyle<'_, T>,
error_emitter: &mut E,
state: &mut UpsertState<'_, S, Option<FromTime>>,
) where
S: UpsertStateBackend<Option<FromTime>>,
G: Scope,
T: PartialOrder + Ord + Clone + Debug,
FromTime: timely::ExchangeData + Ord,
E: UpsertErrorEmitter<G>,
{
stash.sort_unstable();
// Find the prefix that we can emit
let idx = stash.partition_point(|(ts, _, _, _)| match &drain_style {
DrainStyle::ToUpper(upper) => !upper.less_equal(ts),
DrainStyle::AtTime(time) => ts <= time,
});
tracing::trace!(?drain_style, updates = idx, "draining stash in upsert");
// Read the previous values _per key_ out of `state`, recording it
// along with the value with the _latest timestamp for that key_.
commands_state.clear();
for (_, key, _, _) in stash.iter().take(idx) {
commands_state.entry(*key).or_default();
}
// These iterators iterate in the same order because `commands_state`
// is an `IndexMap`.
multi_get_scratch.clear();
multi_get_scratch.extend(commands_state.iter().map(|(k, _)| *k));
match state
.multi_get(multi_get_scratch.drain(..), commands_state.values_mut())
.await
{
Ok(_) => {}
Err(e) => {
error_emitter
.emit("Failed to fetch records from state".to_string(), e)
.await;
}
}
// From the prefix that can be emitted we can deduplicate based on (ts, key) in
// order to only process the command with the maximum order within the (ts,
// key) group. This is achieved by wrapping order in `Reverse(FromTime)` above.;
let mut commands = stash.drain(..idx).dedup_by(|a, b| {
let ((a_ts, a_key, _, _), (b_ts, b_key, _, _)) = (a, b);
a_ts == b_ts && a_key == b_key
});
let bincode_opts = types::upsert_bincode_opts();
// Upsert the values into `commands_state`, by recording the latest
// value (or deletion). These will be synced at the end to the `state`.
//
// Note that we are effectively doing "mini-upsert" here, using
// `command_state`. This "mini-upsert" is seeded with data from `state`, using
// a single `multi_get` above, and the final state is written out into
// `state` using a single `multi_put`. This simplifies `UpsertStateBackend`
// implementations, and reduces the number of reads and write we need to do.
//
// This "mini-upsert" technique is actually useful in `UpsertState`'s
// `merge_snapshot_chunk` implementation, minimizing gets and puts on
// the `UpsertStateBackend` implementations. In some sense, its "upsert all the way down".
while let Some((ts, key, from_time, value)) = commands.next() {
let mut command_state = if let Entry::Occupied(command_state) = commands_state.entry(key) {
command_state
} else {
panic!("key missing from commands_state");
};
let existing_value = &mut command_state.get_mut().value;
if let Some(cs) = existing_value.as_mut() {
cs.ensure_decoded(bincode_opts);
}
// Skip this command if its order key is below the one in the upsert state.
// Note that the existing order key may be `None` if the existing value
// is from snapshotting, which always sorts below new values/deletes.
let existing_order = existing_value.as_ref().and_then(|cs| cs.order().as_ref());
if existing_order >= Some(&from_time.0) {
// Skip this update. If no later updates adjust this key, then we just
// end up writing the same value back to state. If there
// is nothing in the state, `existing_order` is `None`, and this
// does not occur.
continue;
}
match value {
Some(value) => {
if let Some(old_value) = existing_value
.replace(StateValue::value(value.clone(), Some(from_time.0.clone())))
{
if let Value::Value(old_value, _) = old_value.into_decoded() {
output_updates.push((old_value, ts.clone(), -1));
}
}
output_updates.push((value, ts, 1));
}
None => {
if let Some(old_value) = existing_value.take() {
if let Value::Value(old_value, _) = old_value.into_decoded() {
output_updates.push((old_value, ts, -1));
}
}
// Record a tombstone for deletes.
*existing_value = Some(StateValue::tombstone(Some(from_time.0.clone())));
}
}
}
match state
.multi_put(commands_state.drain(..).map(|(k, cv)| {
(
k,
types::PutValue {
value: cv.value.map(|cv| cv.into_decoded()),
previous_value_metadata: cv.metadata.map(|v| ValueMetadata {
size: v.size.try_into().expect("less than i64 size"),
is_tombstone: v.is_tombstone,
}),
},
)
}))
.await
{
Ok(_) => {}
Err(e) => {
error_emitter
.emit("Failed to update records in state".to_string(), e)
.await;
}
}
}
// Created a struct to hold the configs for upserts.
// So that new configs don't require a new method parameter.
struct UpsertConfig {
// Whether or not to wait for the `input` to reach the `resumption_frontier`
// before we finalize `rehydration`.
wait_for_input_resumption: bool,
shrink_upsert_unused_buffers_by_ratio: usize,
}
fn upsert_inner<G: Scope, FromTime, F, Fut, US>(
input: &Collection<G, (UpsertKey, Option<UpsertValue>, FromTime), Diff>,
mut key_indices: Vec<usize>,
resume_upper: Antichain<G::Timestamp>,
previous: Collection<G, Result<Row, DataflowError>, Diff>,
previous_token: Option<Vec<PressOnDropButton>>,
upsert_metrics: UpsertMetrics,
source_config: crate::source::RawSourceCreationConfig,
state: F,
upsert_config: UpsertConfig,
prevent_snapshot_buffering: bool,
snapshot_buffering_max: Option<usize>,
) -> (
Collection<G, Result<Row, DataflowError>, Diff>,
Stream<G, (OutputIndex, HealthStatusUpdate)>,
PressOnDropButton,
)
where
G::Timestamp: TotalOrder,
F: FnOnce() -> Fut + 'static,
Fut: std::future::Future<Output = US>,
US: UpsertStateBackend<Option<FromTime>>,
FromTime: timely::ExchangeData + Ord,
{
// Sort key indices to ensure we can construct the key by iterating over the datums of the row
key_indices.sort_unstable();
let mut builder = AsyncOperatorBuilder::new("Upsert".to_string(), input.scope());
// We only care about UpsertValueError since this is the only error that we can retract
let previous = previous.flat_map(move |result| {
let value = match result {
Ok(ok) => Ok(ok),
Err(DataflowError::EnvelopeError(err)) => match *err {
EnvelopeError::Upsert(err) => Err(err),
_ => return None,
},
Err(_) => return None,
};
Some((UpsertKey::from_value(value.as_ref(), &key_indices), value))
});
let (mut output_handle, output) = builder.new_output();
let (mut health_output, health_stream) = builder.new_output();
let mut input = builder.new_input_for(
&input.inner,
Exchange::new(move |((key, _, _), _, _)| UpsertKey::hashed(key)),
&output_handle,
);
let mut previous = builder.new_input_for(
&previous.inner,
Exchange::new(|((key, _), _, _)| UpsertKey::hashed(key)),
&output_handle,
);
let upsert_shared_metrics = Arc::clone(&upsert_metrics.shared);
let shutdown_button = builder.build(move |caps| async move {
let [mut output_cap, health_cap]: [_; 2] = caps.try_into().unwrap();
// The order key of the `UpsertState` is `Option<FromTime>`, which implements `Default`
// (as required for `merge_snapshot_chunk`), with slightly more efficient serialization
// than a default `Partitioned`.
let mut state = UpsertState::<_, Option<FromTime>>::new(
state().await,
upsert_shared_metrics,
&upsert_metrics,
source_config.source_statistics,
upsert_config.shrink_upsert_unused_buffers_by_ratio,
);
let mut events = vec![];
let mut snapshot_upper = Antichain::from_elem(Timestamp::minimum());
let mut stash = vec![];
let mut input_upper = Antichain::from_elem(Timestamp::minimum());
let mut legacy_errors_to_correct = vec![];
let mut error_emitter = (&mut health_output, &health_cap);
while !PartialOrder::less_equal(&resume_upper, &snapshot_upper)
|| (upsert_config.wait_for_input_resumption
&& !PartialOrder::less_equal(&resume_upper, &input_upper))
{
let previous_event = tokio::select! {
// Note that these are both cancel-safe. The reason we drain the `input` is to
// ensure the `output_frontier` (and therefore flow control on `previous`) make
// progress.
previous_event = previous.next(), if !PartialOrder::less_equal(
&resume_upper,
&snapshot_upper,
) => {
previous_event
}
input_event = input.next() => {
match input_event {
Some(AsyncEvent::Data(_cap, mut data)) => {
stage_input(
&mut stash,
&mut data,
&input_upper,
&resume_upper,
upsert_config.shrink_upsert_unused_buffers_by_ratio
);
}
Some(AsyncEvent::Progress(upper)) => {
input_upper = upper;
}
None => {
input_upper = Antichain::new();
}
}
continue;
}
};
match previous_event {
Some(AsyncEvent::Data(_cap, data)) => {
events.extend(data.into_iter().filter_map(|((key, value), ts, diff)| {
if !resume_upper.less_equal(&ts) {
Some((key, value, diff))
} else {
None
}
}))
}
Some(AsyncEvent::Progress(upper)) => snapshot_upper = upper,
None => snapshot_upper = Antichain::new(),
};
while let Some(event) = previous.next().now_or_never() {
match event {
Some(AsyncEvent::Data(_cap, data)) => {
events.extend(data.into_iter().filter_map(|((key, value), ts, diff)| {
if !resume_upper.less_equal(&ts) {
Some((key, value, diff))
} else {
None
}
}))
}
Some(AsyncEvent::Progress(upper)) => snapshot_upper = upper,
None => {
snapshot_upper = Antichain::new();
break;
}
}
}
for (_, value, diff) in events.iter_mut() {
if let Err(UpsertError::Value(ref mut err)) = value {
// If we receive a legacy error in the snapshot we will keep a note of it but
// insert a non-legacy error in our state. This is so that if this error is
// ever retracted we will correctly retract the non-legacy version because by
// that time we will have emitted the error correction, which happens before
// processing any of the new source input.
if err.is_legacy_dont_touch_it {
legacy_errors_to_correct.push((err.clone(), diff.clone()));
err.is_legacy_dont_touch_it = false;
}
}
}
match state
.merge_snapshot_chunk(
events.drain(..),
PartialOrder::less_equal(&resume_upper, &snapshot_upper),
)
.await
{
Ok(_) => {
if let Some(ts) = snapshot_upper.clone().into_option() {
// As we shutdown, we could ostensibly get data from later than the
// `resume_upper`, which we ignore above. We don't want our output capability to make
// it further than the `resume_upper`.
if !resume_upper.less_equal(&ts) {
output_cap.downgrade(&ts);
}
}
}
Err(e) => {
UpsertErrorEmitter::<G>::emit(
&mut error_emitter,
"Failed to rehydrate state".to_string(),
e,
)
.await;
}
}
}
drop(events);
drop(previous_token);
// Exchaust the previous input. It is expected to immediately reach the empty
// antichain since we have dropped its token.
//
// Note that we do not need to also process the `input` during this, as the dropped token
// will shutdown the `backpressure` operator
while let Some(_event) = previous.next().await {}
// After snapshotting, our output frontier is exactly the `resume_upper`
if let Some(ts) = resume_upper.as_option() {
output_cap.downgrade(ts);
}
// Now it's time to emit the error corrections. It doesn't matter at what timestamp we emit
// them at because all they do is change the representation. The error count at any
// timestamp remains constant.
upsert_metrics
.legacy_value_errors
.set(u64::cast_from(legacy_errors_to_correct.len()));
if !legacy_errors_to_correct.is_empty() {
tracing::error!(
"unexpected legacy error representation. Found {} occurences",
legacy_errors_to_correct.len()
);
}
consolidation::consolidate(&mut legacy_errors_to_correct);
for (mut error, diff) in legacy_errors_to_correct {
assert!(
error.is_legacy_dont_touch_it,
"attempted to correct non-legacy error"
);
tracing::info!("correcting legacy error {error:?} with diff {diff}");
let time = output_cap.time().clone();
let retraction = Err(UpsertError::Value(error.clone()));
error.is_legacy_dont_touch_it = false;
let insertion = Err(UpsertError::Value(error));
output_handle
.give(&output_cap, (retraction, time.clone(), -diff))
.await;
output_handle
.give(&output_cap, (insertion, time, diff))
.await;
}
tracing::info!(
"timely-{} upsert source {} finished rehydration",
source_config.worker_id,
source_config.id
);
// A re-usable buffer of changes, per key. This is an `IndexMap` because it has to be `drain`-able
// and have a consistent iteration order.
let mut commands_state: indexmap::IndexMap<_, types::UpsertValueAndSize<Option<FromTime>>> =
indexmap::IndexMap::new();
let mut multi_get_scratch = Vec::new();
// Now can can resume consuming the collection
let mut output_updates = vec![];
let mut post_snapshot = true;
while let Some(event) = {
// Synthesize a `Progress` event that allows us to drain the `stash` of values
// obtained during snapshotting.
if post_snapshot {
post_snapshot = false;
Some(AsyncEvent::Progress(input_upper.clone()))
} else {
input.next().await
}
} {
// Buffer as many events as possible. This should be bounded, as new data can't be
// produced in this worker until we yield to timely.
let events = [event]
.into_iter()
.chain(std::iter::from_fn(|| input.next().now_or_never().flatten()))
.enumerate();
let mut partial_drain_time = None;
for (i, event) in events {
match event {
AsyncEvent::Data(cap, mut data) => {
tracing::trace!(
time=?cap.time(),
updates=%data.len(),
"received data in upsert"
);
stage_input(
&mut stash,
&mut data,
&input_upper,
&resume_upper,
upsert_config.shrink_upsert_unused_buffers_by_ratio,
);
let event_time = cap.time();
// If the data is at _exactly_ the output frontier, we can preemptively drain it into the state.
// Data within this set events strictly beyond this time are staged as
// normal.
//
// This is a load-bearing optimization, as it is required to avoid buffering
// the entire source snapshot in the `stash`.
if prevent_snapshot_buffering && output_cap.time() == event_time {
partial_drain_time = Some(event_time.clone());
}
}
AsyncEvent::Progress(upper) => {
tracing::trace!(?upper, "received progress in upsert");
// Ignore progress updates before the `resume_upper`, which is our initial
// capability post-snapshotting.
if PartialOrder::less_than(&upper, &resume_upper) {
continue;
}
// Disable the partial drain as this progress event covers
// the `output_cap` time.
partial_drain_time = None;
drain_staged_input::<_, G, _, _, _>(
&mut stash,
&mut commands_state,
&mut output_updates,
&mut multi_get_scratch,
DrainStyle::ToUpper(&upper),
&mut error_emitter,
&mut state,
)
.await;
// Emit the _consolidated_ changes to the output.
output_handle
.give_container(&output_cap, &mut output_updates)
.await;
if let Some(ts) = upper.as_option() {
output_cap.downgrade(ts);
}
input_upper = upper;
}
}
let events_processed = i + 1;
if let Some(max) = snapshot_buffering_max {
if events_processed >= max {
break;
}
}
}
// If there were staged events that occurred at the capability time, drain
// them. This is safe because out-of-order updates to the same key that are
// drained in separate calls to `drain_staged_input` are correctly ordered by
// their `FromTime` in `drain_staged_input`.
//
// Note also that this may result in more updates in the output collection than
// the minimum. However, because the frontier only advances on `Progress` updates,
// the collection always accumulates correctly for all keys.
if let Some(partial_drain_time) = partial_drain_time {
drain_staged_input::<_, G, _, _, _>(
&mut stash,
&mut commands_state,
&mut output_updates,
&mut multi_get_scratch,
DrainStyle::AtTime(partial_drain_time),
&mut error_emitter,
&mut state,
)
.await;
}
}
});
(
output.as_collection().map(|result| match result {
Ok(ok) => Ok(ok),
Err(err) => Err(DataflowError::from(EnvelopeError::Upsert(err))),
}),
health_stream,
shutdown_button.press_on_drop(),
)
}
#[async_trait::async_trait(?Send)]
trait UpsertErrorEmitter<G> {
async fn emit(&mut self, context: String, e: anyhow::Error);
}
#[async_trait::async_trait(?Send)]
impl<G: Scope> UpsertErrorEmitter<G>
for (
&mut AsyncOutputHandle<
<G as ScopeParent>::Timestamp,
Vec<(OutputIndex, HealthStatusUpdate)>,
Tee<<G as ScopeParent>::Timestamp, Vec<(OutputIndex, HealthStatusUpdate)>>,
>,
&Capability<<G as ScopeParent>::Timestamp>,
)
{
async fn emit(&mut self, context: String, e: anyhow::Error) {
process_upsert_state_error::<G>(context, e, self.0, self.1).await
}
}
/// Emit the given error, and stall till the dataflow is restarted.
async fn process_upsert_state_error<G: Scope>(
context: String,
e: anyhow::Error,
health_output: &mut AsyncOutputHandle<
<G as ScopeParent>::Timestamp,
Vec<(OutputIndex, HealthStatusUpdate)>,
Tee<<G as ScopeParent>::Timestamp, Vec<(OutputIndex, HealthStatusUpdate)>>,
>,
health_cap: &Capability<<G as ScopeParent>::Timestamp>,
) {
let update = HealthStatusUpdate::halting(e.context(context).to_string_with_causes(), None);
health_output.give(health_cap, (0, update)).await;
std::future::pending::<()>().await;
unreachable!("pending future never returns");
}