mz_storage/source/

generator.rs

// 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::collections::BTreeMap;
use std::convert::Infallible;
use std::ops::Rem;
use std::sync::Arc;
use std::time::Duration;

use differential_dataflow::{AsCollection, Hashable};
use futures::StreamExt;
use itertools::Itertools;
use mz_ore::cast::CastFrom;
use mz_ore::iter::IteratorExt;
use mz_ore::now::NowFn;
use mz_repr::{Diff, GlobalId, Row};
use mz_storage_types::errors::DataflowError;
use mz_storage_types::sources::load_generator::{
    Event, Generator, KeyValueLoadGenerator, LoadGenerator, LoadGeneratorOutput,
    LoadGeneratorSourceConnection,
};
use mz_storage_types::sources::{MzOffset, SourceExportDetails, SourceTimestamp};
use mz_timely_util::builder_async::{
    Event as AsyncEvent, OperatorBuilder as AsyncOperatorBuilder, PressOnDropButton,
};
use mz_timely_util::containers::stack::AccountedStackBuilder;
use timely::container::CapacityContainerBuilder;
use timely::dataflow::channels::pact::Pipeline;
use timely::dataflow::operators::core::Partition;
use timely::dataflow::{Scope, StreamVec};
use timely::progress::{Antichain, Timestamp};
use tokio::time::{Instant, interval_at};

use crate::healthcheck::{HealthStatusMessage, HealthStatusUpdate, StatusNamespace};
use crate::source::types::{Probe, SignaledFuture, SourceRender, StackedCollection};
use crate::source::{RawSourceCreationConfig, SourceMessage};

mod auction;
mod clock;
mod counter;
mod datums;
mod key_value;
mod marketing;
mod tpch;

pub use auction::Auction;
pub use clock::Clock;
pub use counter::Counter;
pub use datums::Datums;
pub use tpch::Tpch;

use self::marketing::Marketing;

enum GeneratorKind {
    Simple {
        generator: Box<dyn Generator>,
        tick_micros: Option<u64>,
        as_of: u64,
        up_to: u64,
    },
    KeyValue(KeyValueLoadGenerator),
}

impl GeneratorKind {
    fn new(g: &LoadGenerator, tick_micros: Option<u64>, as_of: u64, up_to: u64) -> Self {
        match g {
            LoadGenerator::Auction => GeneratorKind::Simple {
                generator: Box::new(Auction {}),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::Clock => GeneratorKind::Simple {
                generator: Box::new(Clock {
                    tick_ms: tick_micros
                        .map(Duration::from_micros)
                        .unwrap_or(Duration::from_secs(1))
                        .as_millis()
                        .try_into()
                        .expect("reasonable tick interval"),
                    as_of_ms: as_of,
                }),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::Counter { max_cardinality } => GeneratorKind::Simple {
                generator: Box::new(Counter {
                    max_cardinality: max_cardinality.clone(),
                }),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::Datums => GeneratorKind::Simple {
                generator: Box::new(Datums {}),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::Marketing => GeneratorKind::Simple {
                generator: Box::new(Marketing {}),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::Tpch {
                count_supplier,
                count_part,
                count_customer,
                count_orders,
                count_clerk,
            } => GeneratorKind::Simple {
                generator: Box::new(Tpch {
                    count_supplier: *count_supplier,
                    count_part: *count_part,
                    count_customer: *count_customer,
                    count_orders: *count_orders,
                    count_clerk: *count_clerk,
                    // The default tick behavior 1s. For tpch we want to disable ticking
                    // completely.
                    tick: Duration::from_micros(tick_micros.unwrap_or(0)),
                }),
                tick_micros,
                as_of,
                up_to,
            },
            LoadGenerator::KeyValue(kv) => GeneratorKind::KeyValue(kv.clone()),
        }
    }

    fn render<'scope>(
        self,
        scope: Scope<'scope, MzOffset>,
        config: &RawSourceCreationConfig,
        committed_uppers: impl futures::Stream<Item = Antichain<MzOffset>> + 'static,
        start_signal: impl std::future::Future<Output = ()> + 'static,
    ) -> (
        BTreeMap<
            GlobalId,
            StackedCollection<'scope, MzOffset, Result<SourceMessage, DataflowError>>,
        >,
        StreamVec<'scope, MzOffset, Infallible>,
        StreamVec<'scope, MzOffset, HealthStatusMessage>,
        Vec<PressOnDropButton>,
    ) {
        // figure out which output types from the generator belong to which output indexes
        let mut output_map = BTreeMap::new();
        // Maps the output index to export_id for statistics.
        let mut idx_to_exportid = BTreeMap::new();
        // Make sure that there's an entry for the default output, even if there are no exports
        // that need data output. Certain implementations rely on it (at the time of this comment
        // that includes the key-value load gen source).
        output_map.insert(LoadGeneratorOutput::Default, Vec::new());
        for (idx, (export_id, export)) in config.source_exports.iter().enumerate() {
            let output_type = match &export.details {
                SourceExportDetails::LoadGenerator(details) => details.output,
                // This is an export that doesn't need any data output to it.
                SourceExportDetails::None => continue,
                _ => panic!("unexpected source export details: {:?}", export.details),
            };
            output_map
                .entry(output_type)
                .or_insert_with(Vec::new)
                .push(idx);
            idx_to_exportid.insert(idx, export_id.clone());
        }

        match self {
            GeneratorKind::Simple {
                tick_micros,
                as_of,
                up_to,
                generator,
            } => render_simple_generator(
                generator,
                tick_micros,
                as_of.into(),
                up_to.into(),
                scope,
                config,
                committed_uppers,
                output_map,
            ),
            GeneratorKind::KeyValue(kv) => key_value::render(
                kv,
                scope,
                config.clone(),
                committed_uppers,
                start_signal,
                output_map,
                idx_to_exportid,
            ),
        }
    }
}

impl SourceRender for LoadGeneratorSourceConnection {
    type Time = MzOffset;

    const STATUS_NAMESPACE: StatusNamespace = StatusNamespace::Generator;

    fn render<'scope>(
        self,
        scope: Scope<'scope, MzOffset>,
        config: &RawSourceCreationConfig,
        committed_uppers: impl futures::Stream<Item = Antichain<MzOffset>> + 'static,
        start_signal: impl std::future::Future<Output = ()> + 'static,
    ) -> (
        BTreeMap<
            GlobalId,
            StackedCollection<'scope, MzOffset, Result<SourceMessage, DataflowError>>,
        >,
        StreamVec<'scope, MzOffset, HealthStatusMessage>,
        StreamVec<'scope, MzOffset, Probe<MzOffset>>,
        Vec<PressOnDropButton>,
    ) {
        let generator_kind = GeneratorKind::new(
            &self.load_generator,
            self.tick_micros,
            self.as_of,
            self.up_to,
        );
        let (updates, progress, health, button) =
            generator_kind.render(scope, config, committed_uppers, start_signal);

        let probe_stream = synthesize_probes(
            config.id,
            progress,
            config.timestamp_interval,
            config.now_fn.clone(),
        );

        (updates, health, probe_stream, button)
    }
}

fn render_simple_generator<'scope>(
    generator: Box<dyn Generator>,
    tick_micros: Option<u64>,
    as_of: MzOffset,
    up_to: MzOffset,
    scope: Scope<'scope, MzOffset>,
    config: &RawSourceCreationConfig,
    committed_uppers: impl futures::Stream<Item = Antichain<MzOffset>> + 'static,
    output_map: BTreeMap<LoadGeneratorOutput, Vec<usize>>,
) -> (
    BTreeMap<GlobalId, StackedCollection<'scope, MzOffset, Result<SourceMessage, DataflowError>>>,
    StreamVec<'scope, MzOffset, Infallible>,
    StreamVec<'scope, MzOffset, HealthStatusMessage>,
    Vec<PressOnDropButton>,
) {
    let mut builder = AsyncOperatorBuilder::new(config.name.clone(), scope.clone());

    let (data_output, stream) = builder.new_output::<AccountedStackBuilder<_>>();
    let export_ids: Vec<_> = config.source_exports.keys().copied().collect();
    let partition_count = u64::cast_from(export_ids.len());
    let data_streams: Vec<_> = stream.partition::<CapacityContainerBuilder<_>, _, _>(
        partition_count,
        |((output, data), time, diff): &(
            (usize, Result<SourceMessage, DataflowError>),
            MzOffset,
            Diff,
        )| {
            let output = u64::cast_from(*output);
            (output, (data.clone(), time.clone(), diff.clone()))
        },
    );
    let mut data_collections = BTreeMap::new();
    for (id, data_stream) in export_ids.iter().zip_eq(data_streams) {
        data_collections.insert(*id, data_stream.as_collection());
    }

    let (_progress_output, progress_stream) = builder.new_output::<CapacityContainerBuilder<_>>();
    let (health_output, health_stream) = builder.new_output::<CapacityContainerBuilder<_>>();

    let busy_signal = Arc::clone(&config.busy_signal);
    let source_resume_uppers = config.source_resume_uppers.clone();
    let is_active_worker = config.responsible_for(());
    let source_statistics = config.statistics.clone();
    let button = builder.build(move |caps| {
        SignaledFuture::new(busy_signal, async move {
            let [mut cap, mut progress_cap, health_cap] = caps.try_into().unwrap();

            // We only need this until we reported ourselves as Running.
            let mut health_cap = Some(health_cap);

            if !is_active_worker {
                // Emit 0, to mark this worker as having started up correctly.
                for stats in source_statistics.values() {
                    stats.set_offset_known(0);
                    stats.set_offset_committed(0);
                }
                return;
            }

            let resume_upper = Antichain::from_iter(
                source_resume_uppers
                    .values()
                    .flat_map(|f| f.iter().map(MzOffset::decode_row)),
            );

            let Some(resume_offset) = resume_upper.into_option() else {
                return;
            };

            let now_fn = mz_ore::now::SYSTEM_TIME.clone();

            let start_instant = {
                // We want to have our interval start at a nice round number...
                // for example, if our tick interval is one minute, to start at a minute boundary.
                // However, the `Interval` type from tokio can't be "floored" in that way.
                // Instead, figure out the amount we should step forward based on the wall clock,
                // then apply that to our monotonic clock to make things start at approximately the
                // right time.
                let now_millis = now_fn();
                let now_instant = Instant::now();
                let delay_millis = tick_micros
                    .map(|tick_micros| tick_micros / 1000)
                    .filter(|tick_millis| *tick_millis > 0)
                    .map(|tick_millis| tick_millis - now_millis.rem(tick_millis))
                    .unwrap_or(0);
                now_instant + Duration::from_millis(delay_millis)
            };
            let tick = Duration::from_micros(tick_micros.unwrap_or(1_000_000));
            let mut tick_interval = interval_at(start_instant, tick);

            let mut rows = generator.by_seed(now_fn, None, resume_offset);

            let mut committed_uppers = std::pin::pin!(committed_uppers);

            // If we are just starting up, report 0 as our `offset_committed`.
            let mut offset_committed = if resume_offset.offset == 0 {
                Some(0)
            } else {
                None
            };

            while let Some((output_type, event)) = rows.next() {
                match event {
                    Event::Message(mut offset, (value, diff)) => {
                        // Fast forward any data before the requested as of.
                        if offset <= as_of {
                            offset = as_of;
                        }

                        // If the load generator produces data at or beyond the
                        // requested `up_to`, drop it. We'll terminate the load
                        // generator when the capability advances to the `up_to`,
                        // but the load generator might produce data far in advance
                        // of its capability.
                        if offset >= up_to {
                            continue;
                        }

                        // Once we see the load generator start producing data for some offset,
                        // we report progress beyond that offset, to ensure that a binding can be
                        // minted for the data and it doesn't accumulate in reclocking.
                        let _ = progress_cap.try_downgrade(&(offset + 1));

                        let outputs = match output_map.get(&output_type) {
                            Some(outputs) => outputs,
                            // We don't have an output index for this output type, so drop it
                            None => continue,
                        };

                        let message: Result<SourceMessage, DataflowError> = Ok(SourceMessage {
                            key: Row::default(),
                            value,
                            metadata: Row::default(),
                        });

                        // Some generators always reproduce their TVC from the beginning which can
                        // generate a significant amount of data that will overwhelm the dataflow.
                        // Since those are not required downstream we eagerly ignore them here.
                        if resume_offset <= offset {
                            for (&output, message) in outputs.iter().repeat_clone(message) {
                                data_output
                                    .give_fueled(&cap, ((output, message), offset, diff))
                                    .await;
                            }
                        }
                    }
                    Event::Progress(Some(offset)) => {
                        if resume_offset <= offset && health_cap.is_some() {
                            let health_cap = health_cap.take().expect("known to exist");
                            let export_ids = export_ids.iter().copied();
                            for id in export_ids.map(Some).chain(std::iter::once(None)) {
                                health_output.give(
                                    &health_cap,
                                    HealthStatusMessage {
                                        id,
                                        namespace: StatusNamespace::Generator,
                                        update: HealthStatusUpdate::running(),
                                    },
                                );
                            }
                        }

                        // If we've reached the requested maximum offset, cease.
                        if offset >= up_to {
                            break;
                        }

                        // If the offset is at or below the requested `as_of`, don't
                        // downgrade the capability.
                        if offset <= as_of {
                            continue;
                        }

                        cap.downgrade(&offset);
                        let _ = progress_cap.try_downgrade(&offset);

                        // We only sleep if we have surpassed the resume offset so that we can
                        // quickly go over any historical updates that a generator might choose to
                        // emit.
                        // TODO(petrosagg): Remove the sleep below and make generators return an
                        // async stream so that they can drive the rate of production directly
                        if resume_offset < offset {
                            loop {
                                tokio::select! {
                                    _tick = tick_interval.tick() => {
                                        break;
                                    }
                                    Some(frontier) = committed_uppers.next() => {
                                        if let Some(offset) = frontier.as_option() {
                                            // Offset N means we have committed N offsets (offsets are
                                            // 0-indexed)
                                            offset_committed = Some(offset.offset);
                                        }
                                    }
                                }
                            }

                            // TODO(guswynn): generators have various definitions of "snapshot", so
                            // we are not going to implement snapshot progress statistics for them
                            // right now, but will come back to it.
                            if let Some(offset_committed) = offset_committed {
                                for stats in source_statistics.values() {
                                    stats.set_offset_committed(offset_committed);
                                    // technically we could have _known_ a larger offset
                                    // than the one that has been committed, but we can
                                    // never recover that known amount on restart, so we
                                    // just advance these in lock step.
                                    stats.set_offset_known(offset_committed);
                                }
                            }
                        }
                    }
                    Event::Progress(None) => return,
                }
            }
        })
    });

    (
        data_collections,
        progress_stream,
        health_stream,
        vec![button.press_on_drop()],
    )
}

/// Synthesizes a probe stream that produces the frontier of the given progress stream at the given
/// interval.
///
/// This is used as a fallback for sources that don't support probing the frontier of the upstream
/// system.
fn synthesize_probes<'scope, T: timely::progress::Timestamp>(
    source_id: GlobalId,
    progress: StreamVec<'scope, T, Infallible>,
    interval: Duration,
    now_fn: NowFn,
) -> StreamVec<'scope, T, Probe<T>> {
    let scope = progress.scope();

    let active_worker = usize::cast_from(source_id.hashed()) % scope.peers();
    let is_active_worker = active_worker == scope.index();

    let mut op = AsyncOperatorBuilder::new("synthesize_probes".into(), scope);
    let (output, output_stream) = op.new_output::<CapacityContainerBuilder<_>>();
    let mut input = op.new_input_for(progress, Pipeline, &output);

    op.build(|caps| async move {
        if !is_active_worker {
            return;
        }

        let [cap] = caps.try_into().expect("one capability per output");

        let mut ticker = super::probe::Ticker::new(move || interval, now_fn.clone());

        let minimum_frontier = Antichain::from_elem(Timestamp::minimum());
        let mut frontier = minimum_frontier.clone();
        loop {
            tokio::select! {
                event = input.next() => match event {
                    Some(AsyncEvent::Progress(progress)) => frontier = progress,
                    Some(AsyncEvent::Data(..)) => unreachable!(),
                    None => break,
                },
                // We only report a probe if the source upper frontier is not the minimum frontier.
                // This makes it so the first remap binding corresponds to the snapshot of the
                // source, and because the first binding always maps to the minimum *target*
                // frontier we guarantee that the source will never appear empty.
                probe_ts = ticker.tick(), if frontier != minimum_frontier => {
                    let probe = Probe {
                        probe_ts,
                        upstream_frontier: frontier.clone(),
                    };
                    output.give(&cap, probe);
                }
            }
        }

        let probe = Probe {
            probe_ts: now_fn().into(),
            upstream_frontier: Antichain::new(),
        };
        output.give(&cap, probe);
    });

    output_stream
}