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Cache reconstructed pages on disk

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This commit is contained in:
Konstantin Knizhnik
2022-11-03 19:57:27 +02:00
parent e8dec662e6
commit ba46de96eb
1 changed files with 11 additions and 9 deletions
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20
pageserver/src/page_image_cache.rs
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@@ -8,12 +8,14 @@ use crate::page_cache::MaterializedPageHashKey;
use crate::pgdatadir_mapping::{rel_block_to_key, BlockNumber};
use crate::repository::Key;
use crate::tenant::Timeline;
use crate::virtual_file::VirtualFile;
use anyhow::{bail, Result};
use bytes::Bytes;
use once_cell::sync::OnceCell;
use pageserver_api::reltag::RelTag;
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use std::os::unix::fs::FileExt;
use std::sync::{Arc, Condvar, Mutex};
use utils::{
id::{TenantId, TimelineId},
@@ -46,7 +48,7 @@ pub struct PageImageCache {
free_list: usize, // L1 list of free entries
pages: Vec<CacheEntry>,
hash_table: Vec<usize>, // indexes in pages array
file: Arc<VirtulFile>,
file: Arc<VirtualFile>,
}
///
@@ -87,9 +89,9 @@ impl PageImageCache {
fn new(size: usize) -> Self {
let mut pages: Vec<CacheEntry> = Vec::with_capacity(size + 1);
let hash_table = vec![0usize; size];
let file = arc::new(VirtualFile::open_with_options(
"page.cache",
OpenOptions::new().write(true).create(true).truncate(true)).unwrap());
let file = Arc::new(VirtualFile::open_with_options(
&std::path::PathBuf::from("page.cache"),
std::fs::OpenOptions::new().write(true).create(true).truncate(true)).unwrap());
// Dummy key
let dummy_key = MaterializedPageHashKey {
key: Key::MIN,
@@ -211,17 +213,17 @@ pub fn lookup(timeline: &Timeline, rel: RelTag, blkno: BlockNumber, lsn: Lsn) ->
// cache hit
match &cache.pages[index].state {
PageImageState::Loaded(success) => {
if success {
if *success {
// Pin page
cache.unlink(index);
let file = cache.file.clone();
drop(cache);
let mut buf = [0u8; PAGE_SZ];
file.read_exact_at(&mut buf, index as u64 * PAGE_SZ us u64)?;
file.read_exact_at(&mut buf, index as u64 * PAGE_SZ as u64)?;
cache = this.lock().unwrap();
// Move to the head of LRU list
cache.link_after(0, index);
return Ok(Bytes::from(buf));
return Ok(Bytes::from(buf.to_vec()));
} else {
return Err(anyhow::anyhow!("page loading failed earlier"));
}
@@ -292,7 +294,7 @@ pub fn lookup(timeline: &Timeline, rel: RelTag, blkno: BlockNumber, lsn: Lsn) ->
let mut success = false;
if let Ok(page) = &result {
success = true;
file.write_exact_at(&page, i as u64 * PAGE_SZ as u64)?;
file.write_all_at(&page, index as u64 * PAGE_SZ as u64)?;
}
cache = this.lock().unwrap();
if let PageImageState::Loading(event) = &cache.pages[index].state {
@@ -319,6 +321,6 @@ pub fn lookup(timeline: &Timeline, rel: RelTag, blkno: BlockNumber, lsn: Lsn) ->
cache.free_list = index;
}
// only the first one gets the full error from `get_rel_page_at_lsn`
return res;
return result;
}
}