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Don't hold lock on LayerMap while writing to disk

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This commit is contained in:
Patrick Insinger
2021-09-14 15:23:18 -07:00
committed by Patrick Insinger
parent 91ff09151d
commit 0cbee4a416
2 changed files with 26 additions and 6 deletions
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28
pageserver/src/layered_repository.rs
View File

@@ -1272,13 +1272,34 @@ impl LayeredTimeline {
break;
}
// freeze it
// Freeze the layer.
//
// This is a two-step process. First, we "freeze" the in-memory
// layer, to close it for new writes, and replace the original
// layer with the new frozen in-memory layer (and possibly a new
// open layer to hold changes newer than the cutoff.) Then we write
// the frozen layer to disk, and replace the in-memory frozen layer
// with the new on-disk layers.
let FreezeLayers {
frozen,
open: maybe_new_open,
} = oldest_layer.freeze(last_record_lsn)?;
// replace this layer with the new layers that 'freeze' returned
layers.pop_oldest_open();
if let Some(new_open) = maybe_new_open.clone() {
layers.insert_open(new_open);
}
layers.insert_historic(frozen.clone());
// Write the now-frozen layer to disk. That could take a while, so release the lock while do it
drop(layers);
let new_historics = frozen.write_to_disk(self)?;
layers = self.layers.lock().unwrap();
// Finally, replace the frozen in-memory layer with the new on-disk layers
layers.remove_historic(frozen.as_ref());
if let Some(last_historic) = new_historics.last() {
if let Some(new_open) = &maybe_new_open {
@@ -1286,11 +1307,6 @@ impl LayeredTimeline {
}
}
// replace this layer with the new layers that 'freeze' returned
layers.pop_oldest_open();
if let Some(n) = maybe_new_open {
layers.insert_open(n);
}
for n in new_historics {
layers.insert_historic(n);
}

4
pageserver/src/layered_repository/inmemory_layer.rs
View File

@@ -130,6 +130,10 @@ impl Layer for InMemoryLayer {
}
fn get_end_lsn(&self) -> Lsn {
if let Some(end_lsn) = self.end_lsn {
return Lsn(end_lsn.0 + 1);
}
let inner = self.inner.lock().unwrap();
if let Some(drop_lsn) = inner.drop_lsn {