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96e35e11a6
## Problem We don't have a convenient way to generate WAL records for benchmarks and tests. ## Summary of changes Adds a WAL generator, exposed as an iterator. It currently only generates logical messages (noops), but will be extended to write actual table rows later. Some existing code for WAL generation has been replaced with this generator, to reduce duplication.
73 lines
2.0 KiB
Rust
73 lines
2.0 KiB
Rust
use std::{ffi::CStr, sync::Arc};
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use parking_lot::{Mutex, MutexGuard};
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use postgres_ffi::v16::wal_generator::WalGenerator;
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use utils::lsn::Lsn;
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use super::block_storage::BlockStorage;
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/// Simulation implementation of walproposer WAL storage.
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pub struct DiskWalProposer {
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state: Mutex<State>,
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}
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impl DiskWalProposer {
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pub fn new() -> Arc<DiskWalProposer> {
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Arc::new(DiskWalProposer {
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state: Mutex::new(State {
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internal_available_lsn: Lsn(0),
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prev_lsn: Lsn(0),
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disk: BlockStorage::new(),
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wal_generator: WalGenerator::new(),
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}),
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})
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}
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pub fn lock(&self) -> MutexGuard<State> {
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self.state.lock()
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}
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}
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pub struct State {
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// flush_lsn
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internal_available_lsn: Lsn,
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// needed for WAL generation
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prev_lsn: Lsn,
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// actual WAL storage
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disk: BlockStorage,
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// WAL record generator
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wal_generator: WalGenerator,
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}
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impl State {
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pub fn read(&self, pos: u64, buf: &mut [u8]) {
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self.disk.read(pos, buf);
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// TODO: fail on reading uninitialized data
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}
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pub fn write(&mut self, pos: u64, buf: &[u8]) {
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self.disk.write(pos, buf);
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}
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/// Update the internal available LSN to the given value.
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pub fn reset_to(&mut self, lsn: Lsn) {
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self.internal_available_lsn = lsn;
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self.prev_lsn = Lsn(0); // Safekeeper doesn't care if this is omitted
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self.wal_generator.lsn = self.internal_available_lsn;
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self.wal_generator.prev_lsn = self.prev_lsn;
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}
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/// Get current LSN.
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pub fn flush_rec_ptr(&self) -> Lsn {
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self.internal_available_lsn
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}
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/// Inserts a logical record in the WAL at the current LSN.
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pub fn insert_logical_message(&mut self, prefix: &CStr, msg: &[u8]) {
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let record = self.wal_generator.generate_logical_message(prefix, msg);
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self.disk.write(self.internal_available_lsn.into(), &record);
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self.prev_lsn = self.internal_available_lsn;
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self.internal_available_lsn += record.len() as u64;
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}
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}
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