tusharagrahari commented on code in PR #3568: URL: https://github.com/apache/iggy/pull/3568#discussion_r4263325597
########## core/connectors/sources/mysql_source/src/lib.rs: ########## @@ -0,0 +1,4071 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use async_trait::async_trait; +use base64::Engine; +use chrono::{NaiveDate, NaiveDateTime, NaiveTime}; +use humantime::Duration as HumanDuration; +use iggy_common::{DateTime, Utc}; +use iggy_connector_sdk::{ + ConnectorState, Error, ProducedMessage, ProducedMessages, Schema, Source, + source::SourceBatchResult, source_connector, +}; +use secrecy::{ExposeSecret, SecretString}; +use serde::{Deserialize, Serialize}; +use sqlx::mysql::{MySqlDatabaseError, MySqlRow}; +use sqlx::{Column, MySql, Pool, Row, TypeInfo, mysql::MySqlPoolOptions}; +use std::cmp::Ordering as CmpOrdering; +use std::collections::{HashMap, HashSet}; +use std::str::FromStr; +use std::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, Ordering}; +use std::time::Duration; +use tokio::sync::Mutex; +use tracing::{debug, error, info, warn}; +use uuid::Uuid; + +source_connector!(MySqlSource); + +const DEFAULT_MAX_RETRIES: u32 = 3; +const DEFAULT_RETRY_DELAY: &str = "1s"; + +/// Fixed namespace so a given (table, key) always hashes to the same message id +/// across restarts. This is what makes a replayed row idempotent for downstream +/// dedup, so the value must never change once connectors are in the field. +const MESSAGE_ID_NAMESPACE: Uuid = Uuid::from_u128(0x8f3b1e6a4c9d4f2a9b7c0d1e2f3a4b5c); + +/// A disabled table is skipped before anything is logged, so without a reminder the +/// only evidence a connector went dark is the single line written when it happened. +/// At the default 10s poll interval this repeats it every ten minutes. +const DISABLED_TABLES_LOG_INTERVAL: u64 = 60; + +/// How many consecutive polls a table may end in `CursorRegression` before the repeat +/// stops reading as transient. Nothing is published in the meantime, so past this it +/// is a stall the operator has to see. +const CURSOR_REGRESSION_ERROR_THRESHOLD: u32 = 3; + +/// Upper bound on applying a batch's staged mark/delete after its Ack. The SDK waits +/// `BATCH_RESULT_TIMEOUT` (30s) for the result, so this has to finish well inside it. +const ACK_BATCH_TIMEOUT: Duration = Duration::from_secs(10); + +/// MySQL rejects a prepared statement with more placeholders than this (error 1390), and +/// the mark/delete binds one per row of the batch. +const MAX_CLEANUP_BATCH_SIZE: u32 = 65_535; + +/// How many mark/delete statements in a row may fail before the connector stops. The +/// operations stay in the persisted state and run again on restart. +const MAX_CONSECUTIVE_CLEANUP_FAILURES: u32 = 3; + +#[derive(Debug)] +pub struct MySqlSource { + pub id: u32, + pool: Option<Pool<MySql>>, + config: MySqlSourceConfig, + state: Mutex<State>, + pending_batch: Mutex<Option<PendingBatch>>, + consecutive_cleanup_failures: AtomicU32, + verified_cleanup_keys: Mutex<HashSet<String>>, + verbose: bool, + retry_delay: Duration, + poll_interval: Duration, + last_batch_full: AtomicBool, + poisoned_tables: Mutex<HashSet<String>>, + tracking_kinds: Mutex<HashMap<String, OffsetKind>>, + polls: AtomicU64, + cursor_regressions: Mutex<HashMap<String, u32>>, +} + +#[derive(Debug, Clone, Serialize, Deserialize)] +#[serde(deny_unknown_fields)] +pub struct MySqlSourceConfig { + #[serde(serialize_with = "iggy_common::serde_secret::serialize_secret")] + pub connection_string: SecretString, + pub tables: Vec<String>, + pub poll_interval: Option<String>, + pub batch_size: Option<u32>, + pub tracking_column: Option<String>, + pub initial_offset: Option<String>, + pub max_connections: Option<u32>, + pub custom_query: Option<String>, + pub snake_case_columns: Option<bool>, + pub include_metadata: Option<bool>, + pub delete_after_read: Option<bool>, + pub processed_column: Option<String>, + pub primary_key_column: Option<String>, + pub payload_column: Option<String>, + pub payload_format: Option<String>, + pub verbose_logging: Option<bool>, + pub max_retries: Option<u32>, + pub retry_delay: Option<String>, +} + +#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)] +pub enum PayloadFormat { + #[default] + Json, + Bytea, + Text, + JsonDirect, +} + +struct ProcessedRow { + message: ProducedMessage, + tracking_value: Option<String>, + row_pk: Option<PkValue>, +} + +/// Why a table's batch could not be produced. +enum FetchError { + Ordering(String), + /// The batch opened below the cursor it was told to resume from, so the query's + /// filter and the cursor disagree about what "past the offset" means. Retried + /// rather than latched, because unlike a within-batch decrease it depends on the + /// rows as much as on the query: a `custom_query` whose WHERE admits rows the + /// cursor does not gate (an OR branch is the usual one) only fails while such a + /// row is there, so it can clear without a config change. + CursorRegression(String), + MissingTrackingColumn(String), + UnusableTrackingValue(String), + StaleOffsetKind(String), + Other(Error), +} + +impl From<Error> for FetchError { + fn from(error: Error) -> Self { + FetchError::Other(error) + } +} + +/// How MySQL ordered a tracking column, which offsets alone cannot reveal: they are +/// carried as strings, so an `INT` 10 and a `VARCHAR` "10" are indistinguishable by +/// content while the server orders them differently. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +enum OffsetKind { + Numeric, + Lexical, + Unknown, +} + +/// Maps an `information_schema.columns.data_type` to the order MySQL sorts it in. +/// `decimal` belongs with the numbers even though `extract_column_value` renders it +/// as a string to preserve precision. +fn offset_kind_for_data_type(data_type: &str) -> OffsetKind { + const NUMERIC: &[&str] = &[ + "tinyint", + "smallint", + "mediumint", + "int", + "integer", + "bigint", + "decimal", + "numeric", + "float", + "double", + "real", + "bit", + "year", + ]; + if NUMERIC + .iter() + .any(|numeric| data_type.eq_ignore_ascii_case(numeric)) + { + OffsetKind::Numeric + } else { + OffsetKind::Lexical + } +} + +/// Whether MySQL orders the column by its collation. The other lexically compared +/// types are the temporal ones, which render fixed-width and so compare the same way +/// as text no matter what the collation is. +fn is_collation_ordered(data_type: &str) -> bool { + const TEXT: &[&str] = &[ + "char", + "varchar", + "tinytext", + "text", + "mediumtext", + "longtext", + ]; + TEXT.iter().any(|text| data_type.eq_ignore_ascii_case(text)) +} + +fn offset_kind_for_type_name(type_name: &str) -> OffsetKind { + match type_name { + "TINYINT" | "SMALLINT" | "MEDIUMINT" | "INT" | "BIGINT" | "TINYINT UNSIGNED" + | "SMALLINT UNSIGNED" | "MEDIUMINT UNSIGNED" | "INT UNSIGNED" | "BIGINT UNSIGNED" + | "FLOAT" | "DOUBLE" | "DECIMAL" | "BIT" | "YEAR" => OffsetKind::Numeric, + "DATE" | "TIME" | "DATETIME" | "TIMESTAMP" | "CHAR" | "VARCHAR" | "TINYTEXT" | "TEXT" + | "MEDIUMTEXT" | "LONGTEXT" => OffsetKind::Lexical, + _ => OffsetKind::Unknown, + } +} + +fn unusable_tracking_type(data_type: &str) -> Option<&'static str> { + const BINARY: &[&str] = &[ + "binary", + "varbinary", + "tinyblob", + "blob", + "mediumblob", + "longblob", + ]; + + if data_type.eq_ignore_ascii_case("json") { + return Some("it yields no ordered scalar cursor"); + } + // Judged on `data_type` rather than on the `tinyint(1)` display width that spells + // BOOLEAN, because that width is not reliably reported: MySQL 8.0.19 and later drop + // it for unsigned columns while MariaDB keeps it. + if data_type.eq_ignore_ascii_case("tinyint") { + return Some("it has too few distinct values to be unique per row"); + } + if BINARY + .iter() + .any(|binary| data_type.eq_ignore_ascii_case(binary)) + { + return Some("binary values are compared as base64 text, which does not keep byte order"); + } + if data_type.eq_ignore_ascii_case("enum") || data_type.eq_ignore_ascii_case("set") { + return Some("MySQL orders these by declaration index, not by label"); + } + None +} + +/// What a `custom_query` may begin with. `TABLE` is MySQL 8.0.19's table statement, +/// and `(` opens a parenthesized query such as `(SELECT ...) UNION (SELECT ...)`. +const READ_STATEMENT_STARTS: &[&str] = &["SELECT", "WITH", "TABLE", "("]; + +/// The token that decides which statement a query is, skipping leading comments in +/// all three MySQL spellings. Returns a single character when the statement does not +/// open with a word, so a parenthesized query is still recognisable. +fn leading_statement_token(query: &str) -> Option<String> { + let mut rest = query.trim_start(); + loop { + rest = if let Some(after) = rest.strip_prefix("/*") { + after.split_once("*/")?.1.trim_start() + } else if rest.starts_with("--") || rest.starts_with('#') { + rest.split_once('\n')?.1.trim_start() + } else { + break; + }; + } + + let word: String = rest + .chars() + .take_while(|c| c.is_ascii_alphanumeric() || *c == '_') + .collect(); + if word.is_empty() { + return rest.chars().next().map(String::from); + } + Some(word.to_uppercase()) +} + +/// The order the tracking column sorts in according to the result set that just +/// came back, or `None` when the query did not project the column under that name. +fn observed_tracking_kind(row: &MySqlRow, tracking_column: &str) -> Option<OffsetKind> { + row.columns() + .iter() + .find(|column| column.name().eq_ignore_ascii_case(tracking_column)) + .map(|column| offset_kind_for_type_name(column.type_info().name())) + .filter(|kind| *kind != OffsetKind::Unknown) +} + +/// `Clone` so the passing case, which is every batch, walks the names without collecting. +fn ensure_tracking_column_projected<'a>( + projected: impl IntoIterator<Item = &'a str> + Clone, + tracking_column: &str, +) -> Result<(), FetchError> { + if projected + .clone() + .into_iter() + .any(|column| column.eq_ignore_ascii_case(tracking_column)) + { + return Ok(()); + } + Err(FetchError::MissingTrackingColumn(format!( + "the result set has no column '{tracking_column}', it returned [{}]", + projected.into_iter().collect::<Vec<_>>().join(", ") + ))) +} + +fn unusable_tracking_value(tracking_column: &str, pk: &str) -> FetchError { + FetchError::UnusableTrackingValue(format!( + "row (pk {pk}) has no usable value for tracking_column '{tracking_column}': it is NULL \ + or not an ordered scalar (tinyint(1), JSON)" + )) +} + +/// Verifies rows arrive non-decreasing in the tracking column, which is what makes +/// "cursor = last row's value" correct. The built polling query orders ascending by +/// construction, so this only ever fires on a `custom_query`, where the operator +/// owns the `ORDER BY`. +struct OrderingGuard<'a> { + tracking_column: &'a str, + kind: OffsetKind, + last: Option<String>, + /// True while `last` still holds the cursor carried in from the previous poll + /// rather than a value from this batch. Distinguishes the two violations, and + /// keeps an empty batch from re-persisting the offset it started with. + at_cursor: bool, +} + +enum OrderingViolation { + WithinBatch(String), + BelowCursor(String), +} + +impl<'a> OrderingGuard<'a> { + fn new(tracking_column: &'a str, kind: OffsetKind, cursor: Option<String>) -> Self { + OrderingGuard { + tracking_column, + kind, + at_cursor: cursor.is_some(), + last: cursor, + } + } + + fn accept(&mut self, value: String) -> Result<(), OrderingViolation> { + if let Some(previous) = &self.last + && offset_decreased(previous, &value, self.kind) + { + let column = self.tracking_column; + return Err(if self.at_cursor { + OrderingViolation::BelowCursor(format!( + "row '{value}' is below the stored offset '{previous}' for tracking_column \ + '{column}'. Filter the query with `{column} > $offset`" + )) + } else { + OrderingViolation::WithinBatch(format!( + "rows arrived out of order by tracking_column '{column}': '{previous}' \ + preceded '{value}'. Order the query ascending by '{column}'" + )) + }); + } + self.last = Some(value); + self.at_cursor = false; + Ok(()) + } + + /// `None` when no row was accepted, so an empty batch leaves the stored offset + /// untouched rather than rewriting the cursor it was seeded with. + fn into_cursor(self) -> Option<String> { + if self.at_cursor { None } else { self.last } + } +} + +struct TableBatch { + table: String, + messages: Vec<ProducedMessage>, + processed_ids: Vec<PkValue>, + max_offset: Option<String>, +} + +impl PayloadFormat { + fn from_config(s: Option<&str>) -> Self { + match s.map(|s| s.to_lowercase()).as_deref() { + Some("bytea") | Some("raw") => PayloadFormat::Bytea, + Some("text") => PayloadFormat::Text, + Some("json_direct") | Some("jsonb") => PayloadFormat::JsonDirect, + _ => PayloadFormat::Json, + } + } +} + +/// A primary-key value in a form the mark/delete `WHERE pk IN (...)` can bind +/// faithfully. `Text` covers ints/strings/dates/decimals (MySQL implicitly +/// converts the bound string to the column type). `Bytes` carries raw binary +/// (BINARY/VARBINARY/BLOB) so a UUID stored as bytes matches the row instead of +/// being compared as its base64 text, which never matches. +#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)] +enum PkValue { + Text(String), + Bytes(Vec<u8>), +} + +impl PkValue { + fn as_key(&self) -> String { + match self { + PkValue::Text(text) => text.clone(), + PkValue::Bytes(bytes) => base64::engine::general_purpose::STANDARD.encode(bytes), + } + } +} + +#[derive(Debug, Serialize, Deserialize)] +pub struct DatabaseRecord { + pub table_name: String, + pub operation_type: String, + pub timestamp: DateTime<Utc>, + pub data: serde_json::Value, + pub old_data: Option<serde_json::Value>, +} +#[derive(Clone, Copy)] +struct RowProcessingConfig<'a> { + table: &'a str, + tracking_column: &'a str, + pk_column: &'a str, + payload_format: PayloadFormat, + payload_col: &'a str, + snake_case_columns: bool, + include_metadata: bool, +} + +#[derive(Debug, Clone, Serialize, Deserialize)] +struct State { + tracking_offsets: HashMap<String, String>, + processed_rows: u64, + /// Mark/delete work for a batch the runtime has already sent. It is persisted with + /// the batch's offsets so a crash between the send and the cleanup reruns it. + #[serde(default)] + pending_operations: Vec<PendingOperation>, +} + +/// The rows of one table to mark or delete once their batch is acknowledged. +#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)] +struct PendingOperation { + table: String, + ids: Vec<PkValue>, + target: CleanupTarget, +} + +#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)] +struct CleanupTarget { + key_column: String, + action: CleanupAction, +} + +#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)] +enum CleanupAction { + Delete, + MarkProcessed { column: String }, +} + +/// The candidate state of the batch most recently handed to the runtime. Live state +/// only takes it over on Ack, so a Nack leaves offsets and rows where they were. +#[derive(Debug, Clone)] +struct PendingBatch { + state: State, + /// The runtime has delivered the batch but its cleanup has not finished yet. + acknowledged: bool, + /// Cleanup finished and the next poll must persist `state` without the operations, + /// so a restart does not run them again. + retiring: bool, +} + +struct PolledBatch { + messages: Vec<ProducedMessage>, + pending: Option<PendingBatch>, +} + +enum CleanupKeyCheck { + Unique, + NotUnique, + TableMissing, +} + +const CONNECTOR_NAME: &str = "MySQL source"; + +#[async_trait] +impl Source for MySqlSource { + async fn open(&mut self) -> Result<(), Error> { + info!( + "Opening MySQL source connector with ID: {}, Tables: {:?}", + self.id, self.config.tables + ); + + if self.config.tables.is_empty() { + return Err(Error::InitError( + "tables must not be empty, list the table even when custom_query hardcodes it" + .to_string(), + )); + } + + if self.config.batch_size == Some(0) { + return Err(Error::InitError( + "batch_size must be greater than 0; omit it to use the default of 1000".to_string(), + )); + } + + if let Some(batch_size) = self.config.batch_size + && batch_size > MAX_CLEANUP_BATCH_SIZE + && self.cleanup_target().is_some() + { + return Err(Error::InitError(format!( + "batch_size {batch_size} exceeds {MAX_CLEANUP_BATCH_SIZE} with delete_after_read or \ + processed_column set, MySQL allows at most {MAX_CLEANUP_BATCH_SIZE} placeholders \ + in the statement that marks or deletes a batch" + ))); + } + + if self.config.batch_size == Some(1) + && self + .config + .custom_query + .as_deref() + .is_some_and(|query| query.contains("$offset")) + { + return Err(Error::InitError( + "batch_size must be greater than 1 when custom_query filters on $offset" + .to_string(), + )); + } + + if self + .config + .tracking_column + .as_deref() + .is_none_or(str::is_empty) + { + let guidance = if self.config.custom_query.is_some() { + "name the column custom_query orders by and filters with $offset" + } else { + "use a unique, monotonically increasing column" + }; + return Err(Error::InitError(format!( + "tracking_column must be set, {guidance}" + ))); + } + + if let Some(ref col) = self.config.payload_column + && !col.is_empty() + && PayloadFormat::from_config(self.config.payload_format.as_deref()) + == PayloadFormat::Json + { + return Err(Error::InitError( + "payload_format must be 'bytea', 'text', or 'json_direct' when payload_column is set" + .to_string(), + )); + } + + // custom_query never changes after startup, so validate it once here + if let Some(ref query) = self.config.custom_query { + self.validate_custom_query(query)?; + + if query.contains("$offset") && self.config.initial_offset.is_none() { + let state = self.state.lock().await; + let missing: Vec<&str> = self + .config + .tables + .iter() + .filter(|t| !state.tracking_offsets.contains_key(*t)) + .map(String::as_str) + .collect(); + if !missing.is_empty() { + return Err(Error::InitError(format!( + "custom_query uses $offset but initial_offset is not set and no stored offset exists for table(s): {}", + missing.join(", ") + ))); + } + } + } + + if self.config.delete_after_read.unwrap_or(false) && self.config.processed_column.is_some() + { + warn!( + "both delete_after_read and processed_column are set; delete_after_read takes precedence, so rows are deleted and processed_column only acts as a poll filter" + ); + } + + self.validate_pending_cleanup()?; + self.connect().await?; + *self.tracking_kinds.get_mut() = self.resolve_tracking_columns().await?; + self.validate_cleanup_keys().await?; + + info!( + "MySQL source connector with ID: {} opened successfully", + self.id + ); + Ok(()) + } + + async fn poll(&self) -> Result<ProducedMessages, Error> { + let schema = match self.payload_format() { + PayloadFormat::Bytea => Schema::Raw, + PayloadFormat::Text => Schema::Text, + PayloadFormat::JsonDirect | PayloadFormat::Json => Schema::Json, + }; + + if let Some(state) = self.retiring_state().await { + return Ok(ProducedMessages { + schema, + messages: Vec::new(), + state: Some(self.serialize_pending_state(&state)?), + }); + } + + // Skip the pacing delay while draining a backlog, but never while a cleanup + // retry is pending, or a failing mark/delete would spin without a pause. + let cleanup_pending = self.pending_batch.lock().await.is_some(); + if cleanup_pending || !self.last_batch_full.load(Ordering::Relaxed) { + tokio::time::sleep(self.poll_interval).await; + } + + { + let pending = self.pending_batch.lock().await; + if let Some(pending) = pending.as_ref() { + if !pending.acknowledged { + error!( + "{CONNECTOR_NAME} connector ID: {} was polled while a batch was still in flight", + self.id + ); + return Err(Error::InvalidState); + } + // An empty batch whose Ack retries the cleanup the last one left behind. + return Ok(ProducedMessages { + schema, + messages: Vec::new(), + state: None, + }); + } + } + + let polled = self.poll_tables().await?; + + let processed_rows = match &polled.pending { + Some(pending) => pending.state.processed_rows, + None => self.state.lock().await.processed_rows, + }; + if self.verbose { + info!( + "MySQL source connector ID: {} produced {} messages. Total processed: {}", + self.id, + polled.messages.len(), + processed_rows + ); + } else { + debug!( + "MySQL source connector ID: {} produced {} messages. Total processed: {}", + self.id, + polled.messages.len(), + processed_rows + ); + } + + // Idle cycles stage nothing, so return None to let the runtime skip the fsync. + let persisted_state = polled + .pending + .as_ref() + .map(|pending| self.serialize_pending_state(&pending.state)) + .transpose()?; + *self.pending_batch.lock().await = polled.pending; + + Ok(ProducedMessages { + schema, + messages: polled.messages, + state: persisted_state, + }) + } + + async fn on_batch_result(&self, result: SourceBatchResult) -> Result<(), Error> { + if result == SourceBatchResult::Nack { + // Dropping the candidate leaves the live offsets where they were, so the + // next poll reads the same rows again. Delivered batches keep their cleanup. + let mut pending = self.pending_batch.lock().await; + if pending + .as_ref() + .is_some_and(|pending| !pending.acknowledged && !pending.retiring) + { + pending.take(); + } + return Ok(()); + } + + let Some(PendingBatch { mut state, .. }) = self.pending_batch.lock().await.clone() else { + return Ok(()); + }; + + let operations = std::mem::take(&mut state.pending_operations); + let had_operations = !operations.is_empty(); + let deadline = tokio::time::Instant::now() + ACK_BATCH_TIMEOUT; + let failed_operations = self.apply_pending_operations(operations, deadline).await?; + + if failed_operations.is_empty() { + *self.state.lock().await = state.clone(); + let mut pending = self.pending_batch.lock().await; + if had_operations { + *pending = Some(PendingBatch { + state, + acknowledged: false, + retiring: true, + }); + } else { + pending.take(); + } + } else { + state.pending_operations = failed_operations; + *self.pending_batch.lock().await = Some(PendingBatch { + state, + acknowledged: true, + retiring: false, + }); + } + + Ok(()) + } + + async fn close(&mut self) -> Result<(), Error> { + if let Some(pool) = self.pool.take() { + pool.close().await; + info!("MySQL connection pool closed for connector ID: {}", self.id); + } + + let state = self.state.lock().await; + info!( + "MySQL source connector ID: {} closed. Total rows processed: {}", + self.id, state.processed_rows + ); + Ok(()) + } +} + +impl MySqlSource { + pub fn new(id: u32, config: MySqlSourceConfig, state: Option<ConnectorState>) -> Self { + let verbose = config.verbose_logging.unwrap_or(false); + let restored_state = state + .and_then(|s| s.deserialize::<State>(CONNECTOR_NAME, id)) + .inspect(|s| { + info!( + "Restored state for {CONNECTOR_NAME} connector with ID: {id}. \ + Tracking offsets: {:?}, processed rows: {}", + s.tracking_offsets, s.processed_rows + ); + }); + + let delay_str = config.retry_delay.as_deref().unwrap_or(DEFAULT_RETRY_DELAY); + let retry_delay = HumanDuration::from_str(delay_str) + .map(|duration| duration.into()) + .unwrap_or_else(|_| Duration::from_secs(1)); + let interval_str = config.poll_interval.as_deref().unwrap_or("10s"); + let poll_interval = HumanDuration::from_str(interval_str) + .map(|duration| duration.into()) + .unwrap_or_else(|_| Duration::from_secs(10)); + let state = restored_state.unwrap_or(State { + tracking_offsets: HashMap::new(), + processed_rows: 0, + pending_operations: Vec::new(), + }); + // The runtime only persists a batch's operations after sending it, so restored + // operations belong to a delivered batch and only the cleanup is left to do. + let pending_batch = (!state.pending_operations.is_empty()).then(|| PendingBatch { + state: state.clone(), + acknowledged: true, + retiring: false, + }); + MySqlSource { + id, + pool: None, + config, + state: Mutex::new(state), + pending_batch: Mutex::new(pending_batch), + consecutive_cleanup_failures: AtomicU32::new(0), + verified_cleanup_keys: Mutex::new(HashSet::new()), + verbose, + retry_delay, + poll_interval, + last_batch_full: AtomicBool::new(false), + poisoned_tables: Mutex::new(HashSet::new()), + tracking_kinds: Mutex::new(HashMap::new()), + polls: AtomicU64::new(0), + cursor_regressions: Mutex::new(HashMap::new()), + } + } + + async fn connect(&mut self) -> Result<(), Error> { + let max_connections = self.config.max_connections.unwrap_or(10); + let redacted = redact_connection_string(self.config.connection_string.expose_secret()); + + info!("Connecting to MySQL with max {max_connections} connections: {redacted}"); + + let pool = MySqlPoolOptions::new() + .max_connections(max_connections) + // `format_offset_value` escapes backslashes, which under NO_BACKSLASH_ESCAPES + // would reach MySQL as literal characters and filter on the wrong cursor. + .after_connect(|connection, _| { + Box::pin(async move { + sqlx::query( + "SET SESSION sql_mode = REPLACE(@@SESSION.sql_mode, 'NO_BACKSLASH_ESCAPES', '')", + ) + .execute(&mut *connection) + .await?; + Ok(()) + }) + }) + .connect(self.config.connection_string.expose_secret()) + .await + .map_err(|e| Error::InitError(format!("Failed to connect to MySQL: {e}")))?; + + sqlx::query("SELECT 1") + .execute(&pool) + .await + .map_err(|e| Error::InitError(format!("Database connectivity test failed: {e}")))?; + + self.pool = Some(pool); + info!("Connected to MySQL database with {max_connections} max connections"); + Ok(()) + } + + fn tracking_column(&self) -> &str { + self.config.tracking_column.as_deref().unwrap_or("id") + } + + /// Fail fast if a tracking column can't yield a stable, ordered scalar + /// cursor. `value_as_string` drops NULL, tinyint(1) (decoded as BOOLEAN), + /// and JSON to `None`, which silently stalls offset advancement and re-reads + /// rows every cycle. + async fn resolve_tracking_columns(&self) -> Result<HashMap<String, OffsetKind>, Error> { + // Whether the connector owns the query, and can therefore hold the schema to + // what that query will do with it. + let strict = self.config.custom_query.is_none(); + let pool = self.get_pool()?; + let tracking_column = self.tracking_column(); + let mut kinds = HashMap::with_capacity(self.config.tables.len()); + + for table in &self.config.tables { + let (schema, table_name) = table + .split_once('.') + .map(|(schema, name)| (schema.to_string(), name.to_string())) + .unwrap_or_else(|| (String::new(), table.clone())); + + let row = sqlx::query( + "SELECT is_nullable, data_type, column_type \ + FROM information_schema.columns \ + WHERE table_schema = IF(? = '', DATABASE(), ?) \ + AND table_name = ? AND column_name = ?", + ) + .bind(&schema) + .bind(&schema) + .bind(&table_name) + .bind(tracking_column) + .fetch_optional(pool) + .await + .map_err(|e| { + Error::InitError(format!( + "failed to probe schema for tracking_column '{tracking_column}' on table '{table}': {e}" + )) + })?; + + let Some(row) = row else { + // A missing columns row means either the table doesn't exist yet + // or the column is absent. Only the latter is a misconfiguration: + // a table created after the connector starts is legitimate, so + // defer validation rather than permanently disabling the source. + let table_exists = sqlx::query( + "SELECT 1 FROM information_schema.tables \ + WHERE table_schema = IF(? = '', DATABASE(), ?) \ + AND table_name = ?", + ) + .bind(&schema) + .bind(&schema) + .bind(&table_name) + .fetch_optional(pool) + .await + .map_err(|e| { + Error::InitError(format!("failed to probe existence of table '{table}': {e}")) + })? + .is_some(); + + if !table_exists { + warn!( + "table '{table}' does not exist yet; deferring tracking_column \ + '{tracking_column}' validation until the table is created" + ); + kinds.insert(table.clone(), OffsetKind::Unknown); + continue; + } + + if strict { + return Err(Error::InitError(format!( + "tracking_column '{tracking_column}' not found on table '{table}'" + ))); + } + + warn!( + "tracking_column '{tracking_column}' is not a column of table '{table}'; \ + assuming custom_query projects it. Its comparison order is resolved from \ + the first result set instead." + ); + kinds.insert(table.clone(), OffsetKind::Unknown); + continue; + }; + + // Read by position: MySQL returns information_schema column names + // uppercased (IS_NULLABLE, ...), so try_get by lowercase name misses. + let is_nullable: String = row.try_get(0).map_err(|e| { + Error::InitError(format!( + "failed to read is_nullable for table '{table}': {e}" + )) + })?; + let data_type: String = row.try_get(1).map_err(|e| { + Error::InitError(format!("failed to read data_type for table '{table}': {e}")) + })?; + let column_type: String = row.try_get(2).map_err(|e| { + Error::InitError(format!( + "failed to read column_type for table '{table}': {e}" + )) + })?; + + // The column's type survives a plain projection, so it is worth rejecting + // whatever the query looks like. A custom_query aliasing an expression onto + // a name the table also uses is the one false positive, hence the hint. + if let Some(reason) = unusable_tracking_type(&data_type) { + let aliasing_hint = if self.config.custom_query.is_some() { + " If custom_query aliases a different expression to this name, rename the \ + alias so it does not collide with the column." + } else { + "" + }; + return Err(Error::InitError(format!( + "tracking_column '{tracking_column}' on table '{table}' has type \ + '{column_type}': {reason}. Use an integer, timestamp, or string \ + column.{aliasing_hint}" + ))); + } + + if is_nullable.eq_ignore_ascii_case("YES") { + if strict { + return Err(Error::InitError(format!( + "tracking_column '{tracking_column}' on table '{table}' is nullable; \ + a NULL value stalls offset tracking. Declare it NOT NULL." + ))); + } + warn!( + "tracking_column '{tracking_column}' on table '{table}' is nullable; a row \ + whose value is NULL cannot produce a cursor and will fail that table's batch. \ + Have custom_query exclude those rows, or declare the column NOT NULL." + ); + } + + if is_collation_ordered(&data_type) { + warn!( + "tracking_column '{tracking_column}' on table '{table}' has type \ + '{column_type}': values must be unique and increase in its collation order \ + (zero-pad numbers, prefer a _bin collation)" + ); + } + + kinds.insert(table.clone(), offset_kind_for_data_type(&data_type)); + } + Ok(kinds) + } + + fn payload_format(&self) -> PayloadFormat { + if let Some(ref payload_col) = self.config.payload_column + && !payload_col.is_empty() + { + return PayloadFormat::from_config(self.config.payload_format.as_deref()); + } + PayloadFormat::Json + } + + fn serialize_state(&self, state: &State) -> Option<ConnectorState> { + ConnectorState::serialize(state, CONNECTOR_NAME, self.id) + } + + fn serialize_pending_state(&self, state: &State) -> Result<ConnectorState, Error> { + self.serialize_state(state).ok_or_else(|| { + Error::Serialization(format!("failed to serialize {CONNECTOR_NAME} state")) + }) + } + + async fn retiring_state(&self) -> Option<State> { + self.pending_batch + .lock() + .await + .as_ref() + .filter(|pending| pending.retiring) + .map(|pending| pending.state.clone()) + } + + fn primary_key_column(&self) -> &str { + self.config + .primary_key_column + .as_deref() + .unwrap_or(self.tracking_column()) + } + + fn cleanup_target(&self) -> Option<CleanupTarget> { + let action = if self.config.delete_after_read.unwrap_or(false) { + CleanupAction::Delete + } else if let Some(column) = &self.config.processed_column { + CleanupAction::MarkProcessed { + column: column.clone(), + } + } else { + return None; + }; + Some(CleanupTarget { + key_column: self.primary_key_column().to_string(), + action, + }) + } + + /// Restored operations were staged under the config of the run that wrote them. + /// Running them under a different key or action would touch rows nobody read. + fn validate_pending_cleanup(&mut self) -> Result<(), Error> { + let configured = self.cleanup_target(); + for operation in &self.state.get_mut().pending_operations { + if configured.as_ref() != Some(&operation.target) { + return Err(Error::InitError(format!( + "the cleanup configuration changed while cleanup of {} delivered row(s) in \ + table '{}' is pending; restore primary_key_column '{}' and action {:?}", + operation.ids.len(), + operation.table, + operation.target.key_column, + operation.target.action + ))); + } + } + Ok(()) + } + + /// `WHERE key IN (...)` on a key that repeats marks or deletes every row sharing a + /// value, including ones that were never read. Tables that don't exist yet are + /// checked by the first poll that stages cleanup for them. + async fn validate_cleanup_keys(&mut self) -> Result<(), Error> { + let Some(target) = self.cleanup_target() else { + return Ok(()); + }; + let pool = self.get_pool()?; + let mut verified = HashSet::with_capacity(self.config.tables.len()); + for table in &self.config.tables { + let check = cleanup_key_check(pool, table, &target.key_column) + .await + .map_err(|e| { + Error::InitError(format!( + "failed to check primary_key_column '{}' on table '{table}': {e}", + target.key_column + )) + })?; + match check { + CleanupKeyCheck::Unique => { + verified.insert(table.clone()); + } + CleanupKeyCheck::NotUnique => { + return Err(Error::InitError(not_unique_key_message( + table, + &target.key_column, + ))); + } + CleanupKeyCheck::TableMissing => {} + } + } + *self.verified_cleanup_keys.get_mut() = verified; + Ok(()) + } + + async fn cleanup_key_is_unique( + &self, + pool: &Pool<MySql>, + table: &str, + key_column: &str, + ) -> Result<bool, Error> { + if self.verified_cleanup_keys.lock().await.contains(table) { + return Ok(true); + } + let check = cleanup_key_check(pool, table, key_column) + .await + .map_err(|e| { + Error::Connection(format!( + "failed to check primary_key_column '{key_column}' on table '{table}': {e}" + )) + })?; + match check { + CleanupKeyCheck::Unique => { + self.verified_cleanup_keys + .lock() + .await + .insert(table.to_string()); + Ok(true) + } + CleanupKeyCheck::NotUnique => Ok(false), + CleanupKeyCheck::TableMissing => Err(Error::Connection(format!( + "table '{table}' disappeared before its primary_key_column could be checked" + ))), + } + } + + fn get_pool(&self) -> Result<&Pool<MySql>, Error> { + self.pool + .as_ref() + .ok_or_else(|| Error::InitError("Database not connected".to_string())) + } + + fn extract_payload_column( + &self, + row: &MySqlRow, + column_index: usize, + format: PayloadFormat, + ) -> Result<Vec<u8>, Error> { + let column_name = row.columns()[column_index].name(); + match format { + PayloadFormat::Bytea => { + let bytes: Option<Vec<u8>> = row.try_get(column_index).map_err(|e| { + Error::InvalidRecordValue(format!( + "payload column '{column_name}' as bytea: {e}" + )) + })?; + Ok(bytes.unwrap_or_default()) + } + PayloadFormat::Text => { + let text: Option<String> = row.try_get(column_index).map_err(|e| { + Error::InvalidRecordValue(format!( + "payload column '{column_name}' as text (invalid UTF-8?): {e}" + )) + })?; + Ok(text.unwrap_or_default().into_bytes()) + } + PayloadFormat::JsonDirect => { + let json_value: Option<serde_json::Value> = + row.try_get(column_index).map_err(|e| { + Error::InvalidRecordValue(format!( + "payload column '{column_name}' as json_direct (invalid JSON?): {e}" + )) + })?; + simd_json::to_vec(&json_value.unwrap_or(serde_json::Value::Null)).map_err(|e| { + Error::InvalidRecordValue(format!( + "payload column '{column_name}': failed to serialize JSON: {e}" + )) + }) + } + PayloadFormat::Json => Err(Error::InvalidConfig), // unreachable! if payload_column is there then payload_format can never be json + } + } + + /// Best current knowledge of how a table's tracking values compare. + async fn tracking_kind(&self, table: &str) -> OffsetKind { + self.tracking_kinds + .lock() + .await + .get(table) + .copied() + .unwrap_or(OffsetKind::Unknown) + } + + /// Whether the stored cursor is what limits the rows a poll can see. The built + /// polling query always filters on it; a `custom_query` does so only if it + /// interpolates `$offset`. + fn cursor_gates_query(&self) -> bool { + match &self.config.custom_query { + Some(query) => query.contains("$offset"), + None => true, + } + } + + /// The offset a poll actually resumes from: the stored cursor, or the configured + /// starting point before anything has been stored. + fn effective_offset(&self, last_offset: &Option<String>) -> Option<String> { + last_offset + .clone() + .or_else(|| self.config.initial_offset.clone()) + } + + fn substitute_query_params( + &self, + query: &str, + table: &str, + last_offset: &Option<String>, + batch_size: u32, + kind: OffsetKind, + ) -> Result<String, Error> { + let offset_value = self.effective_offset(last_offset).unwrap_or_default(); + let offset = format_offset_value(&offset_value, kind); + let quoted_table = quote_qualified_identifier(table)?; + let limit = batch_size.to_string(); + let now = Utc::now(); + let now_unix = now.timestamp().to_string(); + let now = now.to_rfc3339(); + let replacements = [ + ("$table", quoted_table.as_str()), + ("$offset", offset.as_str()), + ("$limit", limit.as_str()), + ("$now_unix", now_unix.as_str()), + ("$now", now.as_str()), + ]; + + Ok(substitute_query_tokens(query, &replacements)) + } + + /// The query is substituted as text and re-executed once per configured table on + /// every poll for the life of the process, so a shape that cannot terminate does + /// not fail, it repeats. What can be judged from the text alone is judged here, + /// at startup, rather than left to the first poll. + fn validate_custom_query(&self, query: &str) -> Result<(), Error> { + let tracking_column = self.tracking_column(); + + match leading_statement_token(query) { + None => { + return Err(Error::InitError( + "custom_query has no statement: it is empty, or nothing but comments" + .to_string(), + )); + } + Some(token) if !READ_STATEMENT_STARTS.contains(&token.as_str()) => { + return Err(Error::InitError(format!( + "custom_query must be a read starting with SELECT, WITH or TABLE, found \ + '{token}'" + ))); + } + Some(_) => {} + } + + // Collapsed so `ORDER\nBY` and `ORDER BY` read the same as `ORDER BY`; the + // check hard-fails, so a formatting difference must not decide it. + let normalized = query + .split_whitespace() + .collect::<Vec<_>>() + .join(" ") + .to_uppercase(); + + if query.contains("$offset") { + if !normalized.contains("ORDER BY") { + return Err(Error::InitError(format!( + "custom_query filters on $offset but has no ORDER BY, add \ + `ORDER BY {tracking_column}`" + ))); + } + } else if !self.config.delete_after_read.unwrap_or(false) + && self.config.processed_column.is_none() + { + return Err(Error::InitError(format!( + "custom_query must filter with $offset (`WHERE {tracking_column} > $offset`), or \ + set delete_after_read or processed_column" + ))); + } + + if query.contains("$table") && self.config.tables.is_empty() { + return Err(Error::InitError( + "custom_query uses $table but no tables are configured".to_string(), + )); + } + // Without $table the same SQL is executed once per table, so identical rows + // would be emitted repeatedly, each carrying a different table's metadata, + // message ID, and tracking offset. Table identity is not recoverable from a + // static query, so reject the combination instead of guessing one. + if !query.contains("$table") && self.config.tables.len() > 1 { + return Err(Error::InitError(format!( + "custom_query has no $table placeholder but {} tables are configured ({}), use \ + $table in the query or configure a single table", + self.config.tables.len(), + self.config.tables.join(", ") + ))); + } + Ok(()) + } + + fn build_polling_query( + &self, + table: &str, + tracking_column: &str, + last_offset: &Option<String>, + batch_size: u32, + kind: OffsetKind, + ) -> Result<String, Error> { + let quoted_table = quote_qualified_identifier(table)?; + let quoted_tracking = quote_identifier(tracking_column)?; + + let base_query = format!("SELECT * FROM {quoted_table}"); + + let mut conditions = Vec::new(); + + if let Some(offset) = self.effective_offset(last_offset) { + conditions.push(format!( + "{quoted_tracking} > {}", + format_offset_value(&offset, kind) + )); + } + + if let Some(processed_col) = &self.config.processed_column { + let quoted_processed = quote_identifier(processed_col)?; + conditions.push(format!("{quoted_processed} = FALSE")); + } + + let where_clause = if conditions.is_empty() { + String::new() + } else { + format!(" WHERE {}", conditions.join(" AND ")) + }; + + let order_clause = format!(" ORDER BY {quoted_tracking} ASC"); + let limit_clause = format!(" LIMIT {batch_size}"); + + Ok(format!( + "{base_query}{where_clause}{order_clause}{limit_clause}" + )) + } + + fn get_max_retries(&self) -> u32 { + self.config.max_retries.unwrap_or(DEFAULT_MAX_RETRIES) + } + + async fn apply_pending_operations( + &self, + operations: Vec<PendingOperation>, + deadline: tokio::time::Instant, + ) -> Result<Vec<PendingOperation>, Error> { + let mut failed_operations = Vec::new(); + let mut operations = operations.into_iter(); + while let Some(operation) = operations.next() { + if tokio::time::Instant::now() >= deadline { + failed_operations.push(operation); + failed_operations.extend(operations); + break; + } + let result = tokio::time::timeout_at(deadline, async { + let pool = self.get_pool()?; + self.mark_or_delete_processed_rows(pool, &operation).await + }) + .await; + match result { + Ok(Ok(())) => { + self.consecutive_cleanup_failures + .store(0, Ordering::Relaxed); + } + Ok(Err(error)) => { + self.record_cleanup_failure(&operation, &error)?; + failed_operations.push(operation); + } + Err(_) => { + self.record_cleanup_failure( + &operation, + "cleanup exceeded the 10s budget for one Ack", + )?; + failed_operations.push(operation); + } + } + } + Ok(failed_operations) + } + + fn record_cleanup_failure( + &self, + operation: &PendingOperation, + error: impl std::fmt::Display, + ) -> Result<(), Error> { + let consecutive_failures = self + .consecutive_cleanup_failures + .fetch_add(1, Ordering::Relaxed) + .saturating_add(1); + error!( + "Failed to mark or delete {} delivered row(s) in table '{}' for {CONNECTOR_NAME} \ + connector ID: {}, retrying on the next poll ({consecutive_failures} consecutive \ + failures): {error}", + operation.ids.len(), + operation.table, + self.id + ); + if consecutive_failures >= MAX_CONSECUTIVE_CLEANUP_FAILURES { + return Err(Error::Connection(format!( + "stopping {CONNECTOR_NAME} connector ID {} after {consecutive_failures} \ + consecutive mark/delete failures; the cleanup stays in the saved state and \ + runs again on restart", + self.id + ))); + } + Ok(()) + } + + async fn mark_or_delete_processed_rows( + &self, + pool: &Pool<MySql>, + operation: &PendingOperation, + ) -> Result<(), Error> { + let PendingOperation { table, ids, target } = operation; + if ids.is_empty() { + return Ok(()); + } + + let quoted_table = quote_qualified_identifier(table)?; + let quoted_pk = quote_identifier(&target.key_column)?; + let placeholders = vec!["?"; ids.len()].join(", "); + + let query = match &target.action { + CleanupAction::Delete => { + if self.verbose { + info!("Deleting {} processed rows from '{table}'", ids.len()); + } else { + debug!("Deleting {} processed rows from '{table}'", ids.len()); + } + format!("DELETE FROM {quoted_table} WHERE {quoted_pk} IN ({placeholders})") + } + CleanupAction::MarkProcessed { column } => { + let quoted_processed = quote_identifier(column)?; + if self.verbose { + info!("Marking {} rows as processed in '{table}'", ids.len()); + } else { + debug!("Marking {} rows as processed in '{table}'", ids.len()); + } + format!( + "UPDATE {quoted_table} SET {quoted_processed} = TRUE WHERE {quoted_pk} IN ({placeholders})" + ) + } + }; + + // The query and its binds are rebuilt on every attempt because with_retry + // calls the closure once per try and each `execute` consumes the query. + with_retry( + || { + let mut prepared = sqlx::query(sqlx::AssertSqlSafe(query.as_str())); + for id in ids { + prepared = match id { + PkValue::Text(text) => prepared.bind(text), + PkValue::Bytes(bytes) => prepared.bind(bytes), + }; + } + prepared.execute(pool) + }, + self.get_max_retries(), + self.retry_delay.as_millis() as u64, + ) + .await + .map(|_| ()) + } + + async fn poll_tables(&self) -> Result<PolledBatch, Error> { + let pool = self.get_pool()?; + + let batch_size = self.config.batch_size.unwrap_or(1000); + let tracking_column = self.tracking_column(); + let pk_column = self.primary_key_column(); + + let row_config = RowProcessingConfig { + table: "", + tracking_column, + pk_column, + payload_format: self.payload_format(), + payload_col: self.config.payload_column.as_deref().unwrap_or(""), + snake_case_columns: self.config.snake_case_columns.unwrap_or(false), + include_metadata: self.config.include_metadata.unwrap_or(true), + }; + + // Phase 1: fetch and process every table into its own buffer without any + // side effect. A `process_row` failure is deterministic (a row that cannot + // be decoded fails identically every cycle), so a failing table is logged + // with its resume offset and skipped rather than aborting the whole poll: + // nothing has been marked yet, its rows stay in MySQL, and the remaining + // tables still make progress. The operator sees exactly which table and + // offset to fix. + // + // An ordering violation is handled one step further. Retrying it would + // re-run the same query, re-decode the same rows, and hit the same failure + // forever, so the table is latched off instead of being retried each cycle. + let mut batches: Vec<TableBatch> = Vec::with_capacity(self.config.tables.len()); + let mut any_batch_full = false; + + let poll_number = self.polls.fetch_add(1, Ordering::Relaxed) + 1; + let poisoned = { self.poisoned_tables.lock().await.clone() }; + let mut newly_poisoned: Vec<String> = Vec::new(); + + for table in &self.config.tables { + if poisoned.contains(table) { + continue; + } + + // Get last offset with minimal lock time + let last_offset = { + let state = self.state.lock().await; + state.tracking_offsets.get(table).cloned() + }; + + match self + .fetch_table_batch( + table, + &row_config, + tracking_column, + batch_size, + &last_offset, + ) + .await + { + Ok(batch) => { + if self.verbose { + info!("Fetched {} rows from table '{table}'", batch.messages.len()); + } else { + debug!("Fetched {} rows from table '{table}'", batch.messages.len()); + } + if !batch.messages.is_empty() { + self.cursor_regressions.lock().await.remove(table); + } + // A full batch means the LIMIT was hit, so more rows are waiting. + any_batch_full |= batch.messages.len() as u32 >= batch_size; + batches.push(batch); + } + Err(FetchError::Ordering(reason) | FetchError::MissingTrackingColumn(reason)) => { + error!( + "Table '{table}' at offset {}: {reason}. Table disabled until restart.", + last_offset.as_deref().unwrap_or("<start>") + ); + newly_poisoned.push(table.clone()); + } + Err(FetchError::CursorRegression(reason)) => { + // Cleared only by a batch that carried rows, so the run counts polls + // since the table last published anything. An idle poll produces as + // little as a rejected one does and must not read as recovery. + let consecutive = { + let mut regressions = self.cursor_regressions.lock().await; + let consecutive = regressions.entry(table.clone()).or_insert(0); + *consecutive += 1; + *consecutive + }; + let offset = last_offset.as_deref().unwrap_or("<start>"); + if consecutive >= CURSOR_REGRESSION_ERROR_THRESHOLD { + error!( + "Table '{table}' at offset {offset}: {reason}. Skipping this poll \ + ({consecutive} consecutive polls)." + ); + } else { + warn!("Table '{table}' at offset {offset}: {reason}. Skipping this poll."); + } + } + Err(FetchError::StaleOffsetKind(reason)) => { + warn!( + "Table '{table}' at offset {}: {reason}. Retrying on the next poll.", + last_offset.as_deref().unwrap_or("<start>") + ); + } + Err(FetchError::UnusableTrackingValue(reason)) => { + error!( + "Table '{table}' at offset {}: {reason}. Retrying each poll until the row \ + is fixed.", + last_offset.as_deref().unwrap_or("<start>") + ); + } + Err(FetchError::Other(error)) => { + error!( + "Failed to process table '{table}' at offset {}, skipping this cycle: {error}", + last_offset.as_deref().unwrap_or("<start>") + ); + } + } + } + + if !newly_poisoned.is_empty() { + let mut poisoned_tables = self.poisoned_tables.lock().await; + poisoned_tables.extend(newly_poisoned); + if self + .config + .tables + .iter() + .all(|table| poisoned_tables.contains(table)) + { + error!( + "All configured tables are disabled because their batches cannot yield a \ + cursor; {CONNECTOR_NAME} connector with ID: {} is idle until restarted", + self.id + ); + } + } + + // From the next poll on a disabled table is skipped before anything is logged, + // so the one line written when it was disabled can scroll out of the operator's + // log window and leave a dark connector looking healthy. + if poll_number.is_multiple_of(DISABLED_TABLES_LOG_INTERVAL) { + let poisoned_tables = self.poisoned_tables.lock().await; + if !poisoned_tables.is_empty() { + let mut disabled: Vec<&str> = poisoned_tables.iter().map(String::as_str).collect(); + disabled.sort_unstable(); + error!( + "{} of {} configured table(s) are still disabled and are not being polled by \ + {CONNECTOR_NAME} connector with ID: {}, and will stay that way until it is \ + restarted: {}", + disabled.len(), + self.config.tables.len(), + self.id, + disabled.join(", ") + ); + } + } + + // Phase 2: stage each table's batch. Nothing touches MySQL or the live state + // here: the offsets and the mark/delete are applied in `on_batch_result` once + // the runtime has sent the batch and saved this candidate state, and a Nack + // throws the candidate away so the same rows are read again. + let cleanup_target = self.cleanup_target(); + let mut candidate_state = self.state.lock().await.clone(); + let mut operations = Vec::new(); + let mut messages = Vec::new(); + let mut total_processed: u64 = 0; + + for mut batch in batches { + if let Some(target) = &cleanup_target + && !batch.messages.is_empty() + { + if batch.processed_ids.is_empty() { + error!( + "Table '{}': mark/delete is configured but no primary keys were extracted \ + from {} row(s), skipping this cycle so rows are not published without \ + being marked or deleted (check that '{pk_column}' is projected and scalar)", + batch.table, + batch.messages.len() + ); + continue; + } + + match self + .cleanup_key_is_unique(pool, &batch.table, &target.key_column) + .await + { + Ok(true) => {} + Ok(false) => { + error!( + "{}. Table disabled until restart.", + not_unique_key_message(&batch.table, &target.key_column) + ); + self.poisoned_tables.lock().await.insert(batch.table); + continue; + } + Err(error) => { + error!("Table '{}' skipped this cycle: {error}", batch.table); + continue; + } + } + + operations.push(PendingOperation { + table: batch.table.clone(), + ids: std::mem::take(&mut batch.processed_ids), + target: target.clone(), + }); + } + + total_processed += batch.messages.len() as u64; + messages.append(&mut batch.messages); + if let Some(offset) = batch.max_offset { + candidate_state.tracking_offsets.insert(batch.table, offset); + } + } + + let pending = (total_processed > 0).then(|| { + candidate_state.processed_rows += total_processed; + candidate_state.pending_operations = operations; + PendingBatch { + state: candidate_state, + acknowledged: false, + retiring: false, + } + }); + + self.last_batch_full + .store(any_batch_full, Ordering::Relaxed); + Ok(PolledBatch { messages, pending }) + } + + async fn fetch_table_batch( + &self, + table: &str, + row_config: &RowProcessingConfig<'_>, + tracking_column: &str, + batch_size: u32, + last_offset: &Option<String>, + ) -> Result<TableBatch, FetchError> { + let pool = self.get_pool()?; + let table_config = RowProcessingConfig { + table, + ..*row_config + }; + + let query_kind = self.tracking_kind(table).await; + let query = if let Some(custom_query) = &self.config.custom_query { + self.substitute_query_params(custom_query, table, last_offset, batch_size, query_kind)? + } else { + self.build_polling_query(table, tracking_column, last_offset, batch_size, query_kind)? + }; + + // Database I/O without holding the lock + let rows = with_retry( + || sqlx::query(sqlx::AssertSqlSafe(query.as_str())).fetch_all(pool), + self.get_max_retries(), + self.retry_delay.as_millis() as u64, + ) + .await?; + + // Settled once for the whole batch rather than per row, since the column list + // is a property of the result set. + if let Some(first) = rows.first() { + ensure_tracking_column_projected( + first.columns().iter().map(|column| column.name()), + tracking_column, + )?; + } + + let resume_from = if self.cursor_gates_query() { + self.effective_offset(last_offset) + } else { + None + }; + + // The result set describes what this query actually returned, so it outranks + // whatever `information_schema` said at startup and is the only answer + // available for a computed column. + let kind = match rows.first().and_then(|row| { + observed_tracking_kind(row, tracking_column).filter(|observed| *observed != query_kind) + }) { + Some(observed) => { + self.tracking_kinds + .lock() + .await + .insert(table.to_string(), observed); + // The query was already sent with the stale kind, so its offset literal + // may be quoted for the wrong type. + if let Some(offset) = &resume_from + && offset_literal_diverged(offset, query_kind, observed) + { + return Err(FetchError::StaleOffsetKind(format!( + "tracking_column '{tracking_column}' type differs from the one detected \ + at startup (filtered with {}, expected {}), batch discarded", + format_offset_value(offset, query_kind), + format_offset_value(offset, observed) + ))); + } + observed + } + None => query_kind, + }; + + let mut batch = TableBatch { + table: table.to_string(), + messages: Vec::with_capacity(rows.len()), + processed_ids: Vec::new(), + max_offset: None, + }; + // Every row of a result set shares its columns, so the published key names are + // derived once per batch instead of once per row. + let column_names: Vec<String> = rows + .first() + .map(|row| { + row.columns() + .iter() + .map(|column| { + if table_config.snake_case_columns { + to_snake_case(column.name()) + } else { + column.name().to_string() + } + }) + .collect() + }) + .unwrap_or_default(); + let mut ordering = OrderingGuard::new(tracking_column, kind, resume_from); + for row in rows { + let processed = self + .process_row(&row, &table_config, &column_names) + .map_err(|e| { + error!( + "Failed to decode row in table '{table}' (pk {}): {e}", + pk_for_log(&row, table_config.pk_column) + ); + e + })?; + + let Some(value) = processed.tracking_value else { + return Err(unusable_tracking_value( + tracking_column, + &pk_for_log(&row, table_config.pk_column), + )); + }; + ordering + .accept(value) + .map_err(|violation| match violation { + OrderingViolation::WithinBatch(reason) => FetchError::Ordering(reason), + OrderingViolation::BelowCursor(reason) => FetchError::CursorRegression(reason), + })?; + + if let Some(pk) = processed.row_pk { + batch.processed_ids.push(pk); + } + + batch.messages.push(processed.message); + } + batch.max_offset = ordering.into_cursor(); + + Ok(batch) + } + + fn process_row( + &self, + row: &MySqlRow, + config: &RowProcessingConfig, + column_names: &[String], + ) -> Result<ProcessedRow, Error> { + let mut row_pk: Option<PkValue> = None; + let mut tracking_value: Option<String> = None; + + // Payload column set: only extract it plus tracking/pk columns. + // Avoids extract_column_value on every other column since the data map + // built below would be discarded anyway. + if !config.payload_col.is_empty() { + let mut extracted_payload: Option<Vec<u8>> = None; + for (i, column) in row.columns().iter().enumerate() { + let name = column.name(); + if name.eq_ignore_ascii_case(config.payload_col) { + extracted_payload = + Some(self.extract_payload_column(row, i, config.payload_format)?); + } + let is_tracking = name.eq_ignore_ascii_case(config.tracking_column); + let is_pk = name.eq_ignore_ascii_case(config.pk_column); + if is_tracking { + let value = extract_column_value(row, i)?; + tracking_value = column_value_as_string(row, i, &value)?; + if is_pk { + row_pk = pk_value_from_decoded(row, i, &value)?; + } + } else if is_pk { + row_pk = extract_pk_value(row, i)?; + } + } + + // Every extract_payload_column arm yields Ok for a NULL column, so None + // here means the column was absent. Falling back to the whole-row JSON + // would publish bytes contradicting the schema derived from payload_format. + let payload = extracted_payload.ok_or_else(|| { + Error::InvalidRecordValue(format!( + "table '{}': payload_column '{}' not present in the result set", + config.table, config.payload_col + )) + })?; + + return Ok(build_processed_row( + config.table, + payload, + tracking_value, + row_pk, + )); + } + + let mut data = serde_json::Map::new(); + for ((i, column), column_name) in row.columns().iter().enumerate().zip(column_names) { + let name = column.name(); + let value = extract_column_value(row, i)?; + if name.eq_ignore_ascii_case(config.tracking_column) { + tracking_value = column_value_as_string(row, i, &value)?; + } + if name.eq_ignore_ascii_case(config.pk_column) { + row_pk = pk_value_from_decoded(row, i, &value)?; + } + data.insert(column_name.clone(), value); + } + + let payload = if config.include_metadata { + let record = DatabaseRecord { + table_name: config.table.to_string(), + operation_type: "SELECT".to_string(), + timestamp: Utc::now(), + data: serde_json::Value::Object(data), + old_data: None, + }; + simd_json::to_vec(&record).map_err(|e| { + Error::InvalidRecordValue(format!( + "table '{}': failed to serialize row to JSON: {e}", + config.table + )) + })? + } else { + simd_json::to_vec(&data).map_err(|e| { + Error::InvalidRecordValue(format!( + "table '{}': failed to serialize row to JSON: {e}", + config.table + )) + })? + }; + + Ok(build_processed_row( + config.table, + payload, + tracking_value, + row_pk, + )) + } +} + +/// Type-faithful primary-key extraction. Binary columns are taken as raw bytes +/// rather than routed through the base64 path in `extract_column_value`, so the +/// value can be bound back into `WHERE pk IN (...)` and match the row. Everything +/// else takes the string form MySQL parses back to the same value. Returns None +/// only for a NULL pk, which a real primary key cannot be. +fn extract_pk_value(row: &MySqlRow, column_index: usize) -> Result<Option<PkValue>, Error> { + if is_binary_column(row, column_index) { + return binary_pk_value(row, column_index); + } + let value = extract_column_value(row, column_index)?; + pk_value_from_decoded(row, column_index, &value) +} + +/// Like `extract_pk_value` for a column the caller has already decoded, so the +/// common key column is not decoded a second time per row. +fn pk_value_from_decoded( + row: &MySqlRow, + column_index: usize, + value: &serde_json::Value, +) -> Result<Option<PkValue>, Error> { + if is_binary_column(row, column_index) { + return binary_pk_value(row, column_index); + } + Ok(column_value_as_string(row, column_index, value)?.map(PkValue::Text)) +} + +fn is_binary_column(row: &MySqlRow, column_index: usize) -> bool { + matches!( + row.columns()[column_index].type_info().name(), + "BINARY" | "VARBINARY" | "TINYBLOB" | "BLOB" | "MEDIUMBLOB" | "LONGBLOB" + ) +} + +fn binary_pk_value(row: &MySqlRow, column_index: usize) -> Result<Option<PkValue>, Error> { + let column = &row.columns()[column_index]; + let bytes: Option<Vec<u8>> = row.try_get(column_index).map_err(|e| { + Error::InvalidRecordValue(format!( + "primary key column '{}' (MySQL type '{}'): {e}", + column.name(), + column.type_info().name() + )) + })?; + Ok(bytes.map(PkValue::Bytes)) +} + +fn extract_column_value(row: &MySqlRow, column_index: usize) -> Result<serde_json::Value, Error> { + let column = &row.columns()[column_index]; + let type_name = column.type_info().name(); + + let to_err = |e: sqlx::Error| { + Error::InvalidRecordValue(format!( + "column '{}' (MySQL type '{type_name}'): {e}", + column.name() + )) + }; + + match type_name { + "BOOLEAN" => { + let value: Option<bool> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(serde_json::Value::Bool) + .unwrap_or(serde_json::Value::Null)) + } + "TINYINT" => { + let value: Option<i8> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as i64)) + .unwrap_or(serde_json::Value::Null)) + } + "SMALLINT" => { + let value: Option<i16> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as i64)) + .unwrap_or(serde_json::Value::Null)) + } + "MEDIUMINT" | "INT" => { + let value: Option<i32> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as i64)) + .unwrap_or(serde_json::Value::Null)) + } + "BIGINT" => { + let value: Option<i64> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(serde_json::Value::from) + .unwrap_or(serde_json::Value::Null)) + } + "TINYINT UNSIGNED" => { + let value: Option<u8> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as u64)) + .unwrap_or(serde_json::Value::Null)) + } + "SMALLINT UNSIGNED" => { + let value: Option<u16> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as u64)) + .unwrap_or(serde_json::Value::Null)) + } + "MEDIUMINT UNSIGNED" | "INT UNSIGNED" => { + let value: Option<u32> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as u64)) + .unwrap_or(serde_json::Value::Null)) + } + "BIGINT UNSIGNED" => { + let value: Option<u64> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(serde_json::Value::from) + .unwrap_or(serde_json::Value::Null)) + } + "FLOAT" => { + let value: Option<f32> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(|v| serde_json::Value::from(v as f64)) + .unwrap_or(serde_json::Value::Null)) + } + "DOUBLE" => { + let value: Option<f64> = row.try_get(column_index).map_err(to_err)?; + Ok(value + .map(serde_json::Value::from) + .unwrap_or(serde_json::Value::Null)) + } + "DECIMAL" => { + let value: Option<rust_decimal::Decimal> = row.try_get(column_index).map_err(to_err)?; Review Comment: fixed, DECIMAL is now decoded as BigDecimal and written with to_plain_string(), so payloads and the cursor keep every digit. -- This is an automated message from the Apache Git Service. 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