Files
neon/safekeeper/benches/benchutils.rs
Evan Fleming b593e51eae safekeeper: use arc for global timelines and config (#10051)
Hello! I was interested in potentially making some contributions to Neon
and looking through the issue backlog I found
[8200](https://github.com/neondatabase/neon/issues/8200) which seemed
like a good first issue to attempt to tackle. I see it was assigned a
while ago so apologies if I'm stepping on any toes with this PR. I also
apologize for the size of this PR. I'm not sure if there is a simple way
to reduce it given the footprint of the components being changed.

## Problem
This PR is attempting to address part of the problem outlined in issue
[8200](https://github.com/neondatabase/neon/issues/8200). Namely to
remove global static usage of timeline state in favour of
`Arc<GlobalTimelines>` and to replace wasteful clones of
`SafeKeeperConf` with `Arc<SafeKeeperConf>`. I did not opt to tackle
`RemoteStorage` in this PR to minimize the amount of changes as this PR
is already quite large. I also did not opt to introduce an
`SafekeeperApp` wrapper struct to similarly minimize changes but I can
tackle either or both of these omissions in this PR if folks would like.

## Summary of changes
- Remove static usage of `GlobalTimelines` in favour of
`Arc<GlobalTimelines>`
- Wrap `SafeKeeperConf` in `Arc` to avoid wasteful clones of the
underlying struct

## Some additional thoughts
- We seem to currently store `SafeKeeperConf` in `GlobalTimelines` and
then expose it through a public`get_global_config` function which
requires locking. This seems needlessly wasteful and based on observed
usage we could remove this public accessor and force consumers to
acquire `SafeKeeperConf` through the new Arc reference.
2024-12-09 21:09:20 +00:00

109 lines
4.0 KiB
Rust

use std::sync::Arc;
use camino_tempfile::Utf8TempDir;
use safekeeper::rate_limit::RateLimiter;
use safekeeper::safekeeper::{ProposerAcceptorMessage, ProposerElected, SafeKeeper, TermHistory};
use safekeeper::state::{TimelinePersistentState, TimelineState};
use safekeeper::timeline::{get_timeline_dir, SharedState, StateSK, Timeline};
use safekeeper::timelines_set::TimelinesSet;
use safekeeper::wal_backup::remote_timeline_path;
use safekeeper::{control_file, wal_storage, SafeKeeperConf};
use tokio::fs::create_dir_all;
use utils::id::{NodeId, TenantTimelineId};
use utils::lsn::Lsn;
/// A Safekeeper benchmarking environment. Uses a tempdir for storage, removed on drop.
pub struct Env {
/// Whether to enable fsync.
pub fsync: bool,
/// Benchmark directory. Deleted when dropped.
pub tempdir: Utf8TempDir,
}
impl Env {
/// Creates a new benchmarking environment in a temporary directory. fsync controls whether to
/// enable fsyncing.
pub fn new(fsync: bool) -> anyhow::Result<Self> {
let tempdir = camino_tempfile::tempdir()?;
Ok(Self { fsync, tempdir })
}
/// Constructs a Safekeeper config for the given node ID.
fn make_conf(&self, node_id: NodeId) -> SafeKeeperConf {
let mut conf = SafeKeeperConf::dummy();
conf.my_id = node_id;
conf.no_sync = !self.fsync;
conf.workdir = self.tempdir.path().join(format!("safekeeper-{node_id}"));
conf
}
/// Constructs a Safekeeper with the given node and tenant/timeline ID.
///
/// TODO: we should support using in-memory storage, to measure non-IO costs. This would be
/// easier if SafeKeeper used trait objects for storage rather than generics. It's also not
/// currently possible to construct a timeline using non-file storage since StateSK only accepts
/// SafeKeeper<control_file::FileStorage, wal_storage::PhysicalStorage>.
pub async fn make_safekeeper(
&self,
node_id: NodeId,
ttid: TenantTimelineId,
) -> anyhow::Result<SafeKeeper<control_file::FileStorage, wal_storage::PhysicalStorage>> {
let conf = self.make_conf(node_id);
let timeline_dir = get_timeline_dir(&conf, &ttid);
create_dir_all(&timeline_dir).await?;
let mut pstate = TimelinePersistentState::empty();
pstate.tenant_id = ttid.tenant_id;
pstate.timeline_id = ttid.timeline_id;
let wal = wal_storage::PhysicalStorage::new(&ttid, &timeline_dir, &pstate, conf.no_sync)?;
let ctrl =
control_file::FileStorage::create_new(&timeline_dir, pstate, conf.no_sync).await?;
let state = TimelineState::new(ctrl);
let mut safekeeper = SafeKeeper::new(state, wal, conf.my_id)?;
// Emulate an initial election.
safekeeper
.process_msg(&ProposerAcceptorMessage::Elected(ProposerElected {
term: 1,
start_streaming_at: Lsn(0),
term_history: TermHistory(vec![(1, Lsn(0)).into()]),
timeline_start_lsn: Lsn(0),
}))
.await?;
Ok(safekeeper)
}
/// Constructs a timeline, including a new Safekeeper with the given node ID, and spawns its
/// manager task.
pub async fn make_timeline(
&self,
node_id: NodeId,
ttid: TenantTimelineId,
) -> anyhow::Result<Arc<Timeline>> {
let conf = Arc::new(self.make_conf(node_id));
let timeline_dir = get_timeline_dir(&conf, &ttid);
let remote_path = remote_timeline_path(&ttid)?;
let safekeeper = self.make_safekeeper(node_id, ttid).await?;
let shared_state = SharedState::new(StateSK::Loaded(safekeeper));
let timeline = Timeline::new(
ttid,
&timeline_dir,
&remote_path,
shared_state,
conf.clone(),
);
timeline.bootstrap(
&mut timeline.write_shared_state().await,
&conf,
Arc::new(TimelinesSet::default()), // ignored for now
RateLimiter::new(0, 0),
);
Ok(timeline)
}
}