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Reduce live time of wanted image layer lock

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This commit is contained in:
Konstantin Knizhnik
2023-03-21 11:28:03 +02:00
parent ffdf7df2ea
commit a7cf926aeb
1 changed files with 21 additions and 17 deletions
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38
pageserver/src/tenant/timeline.rs
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@@ -2915,23 +2915,27 @@ impl Timeline {
let layers = self.layers.read().unwrap();
let mut max_deltas = 0;
let wanted_image_layers = self.wanted_image_layers.lock().unwrap();
if let Some((cutoff_lsn, wanted)) = &*wanted_image_layers {
let img_range =
partition.ranges.first().unwrap().start..partition.ranges.last().unwrap().end;
if wanted.overlaps(&img_range) {
//
// gc_timeline only pays attention to image layers that are older than the GC cutoff,
// but create_image_layers creates image layers at last-record-lsn.
// So it's possible that gc_timeline wants a new image layer to be created for a key range,
// but the range is already covered by image layers at more recent LSNs. Before we
// create a new image layer, check if the range is already covered at more recent LSNs.
if !layers.image_layer_exists(&img_range, &(Lsn::min(lsn, *cutoff_lsn)..lsn + 1))? {
debug!(
"Force generation of layer {}-{} wanted by GC, cutoff={}, lsn={})",
img_range.start, img_range.end, cutoff_lsn, lsn
);
return Ok(true);
{
let wanted_image_layers = self.wanted_image_layers.lock().unwrap();
if let Some((cutoff_lsn, wanted)) = &*wanted_image_layers {
let img_range =
partition.ranges.first().unwrap().start..partition.ranges.last().unwrap().end;
if wanted.overlaps(&img_range) {
//
// gc_timeline only pays attention to image layers that are older than the GC cutoff,
// but create_image_layers creates image layers at last-record-lsn.
// So it's possible that gc_timeline wants a new image layer to be created for a key range,
// but the range is already covered by image layers at more recent LSNs. Before we
// create a new image layer, check if the range is already covered at more recent LSNs.
if !layers
.image_layer_exists(&img_range, &(Lsn::min(lsn, *cutoff_lsn)..lsn + 1))?
{
debug!(
"Force generation of layer {}-{} wanted by GC, cutoff={}, lsn={})",
img_range.start, img_range.end, cutoff_lsn, lsn
);
return Ok(true);
}
}
}
}