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Use layer start_lsn instead of *entry_lsn as LSN to continue WAL record traversal at next layer (#573)

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refer #532
This commit is contained in:
Konstantin Knizhnik
2021-09-09 15:15:50 +03:00
committed by GitHub
parent 4fae115dc2
commit 30c0343727
2 changed files with 14 additions and 20 deletions
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17
pageserver/src/layered_repository/delta_layer.rs
View File

@@ -168,7 +168,7 @@ impl Layer for DeltaLayer {
lsn: Lsn,
reconstruct_data: &mut PageReconstructData,
) -> Result<PageReconstructResult> {
let mut cont_lsn: Option<Lsn> = Some(lsn);
let mut need_image = true;
assert!(self.seg.blknum_in_seg(blknum));
@@ -185,12 +185,12 @@ impl Layer for DeltaLayer {
let mut iter = inner
.page_version_metas
.range((Included(&minkey), Included(&maxkey)));
while let Some(((_blknum, entry_lsn), entry)) = iter.next_back() {
while let Some(((_blknum, _entry_lsn), entry)) = iter.next_back() {
if let Some(img_range) = &entry.page_image_range {
// Found a page image, return it
let img = Bytes::from(read_blob(&page_version_reader, img_range)?);
reconstruct_data.page_img = Some(img);
cont_lsn = None;
need_image = false;
break;
} else if let Some(rec_range) = &entry.record_range {
let rec = WALRecord::des(&read_blob(&page_version_reader, rec_range)?)?;
@@ -198,11 +198,8 @@ impl Layer for DeltaLayer {
reconstruct_data.records.push(rec);
if will_init {
// This WAL record initializes the page, so no need to go further back
cont_lsn = None;
need_image = false;
break;
} else {
// This WAL record needs to be applied against an older page image
cont_lsn = Some(*entry_lsn);
}
} else {
// No base image, and no WAL record. Huh?
@@ -215,14 +212,14 @@ impl Layer for DeltaLayer {
// If an older page image is needed to reconstruct the page, let the
// caller know about the predecessor layer.
if let Some(cont_lsn) = cont_lsn {
if need_image {
if let Some(cont_layer) = &self.predecessor {
Ok(PageReconstructResult::Continue(
cont_lsn,
self.start_lsn,
Arc::clone(cont_layer),
))
} else {
Ok(PageReconstructResult::Missing(cont_lsn))
Ok(PageReconstructResult::Missing(self.start_lsn))
}
} else {
Ok(PageReconstructResult::Complete)

17
pageserver/src/layered_repository/inmemory_layer.rs
View File

@@ -137,7 +137,7 @@ impl Layer for InMemoryLayer {
lsn: Lsn,
reconstruct_data: &mut PageReconstructData,
) -> Result<PageReconstructResult> {
let mut cont_lsn: Option<Lsn> = Some(lsn);
let mut need_image = true;
assert!(self.seg.blknum_in_seg(blknum));
@@ -150,20 +150,17 @@ impl Layer for InMemoryLayer {
let mut iter = inner
.page_versions
.range((Included(&minkey), Included(&maxkey)));
while let Some(((_blknum, entry_lsn), entry)) = iter.next_back() {
while let Some(((_blknum, _entry_lsn), entry)) = iter.next_back() {
if let Some(img) = &entry.page_image {
reconstruct_data.page_img = Some(img.clone());
cont_lsn = None;
need_image = false;
break;
} else if let Some(rec) = &entry.record {
reconstruct_data.records.push(rec.clone());
if rec.will_init {
// This WAL record initializes the page, so no need to go further back
cont_lsn = None;
need_image = false;
break;
} else {
// This WAL record needs to be applied against an older page image
cont_lsn = Some(*entry_lsn);
}
} else {
// No base image, and no WAL record. Huh?
@@ -176,14 +173,14 @@ impl Layer for InMemoryLayer {
// If an older page image is needed to reconstruct the page, let the
// caller know about the predecessor layer.
if let Some(cont_lsn) = cont_lsn {
if need_image {
if let Some(cont_layer) = &self.predecessor {
Ok(PageReconstructResult::Continue(
cont_lsn,
self.start_lsn,
Arc::clone(cont_layer),
))
} else {
Ok(PageReconstructResult::Missing(cont_lsn))
Ok(PageReconstructResult::Missing(self.start_lsn))
}
} else {
Ok(PageReconstructResult::Complete)