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fix(pageserver): barrier should wait for deletions

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Signed-off-by: Alex Chi Z <chi@neon.tech>
This commit is contained in:
Alex Chi Z
2024-11-05 11:38:18 -05:00
parent 2f1a56c8f9
commit 3ceb9f8ec9
1 changed files with 28 additions and 5 deletions
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33
pageserver/src/tenant/remote_timeline_client.rs
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@@ -1756,10 +1756,7 @@ impl RemoteTimelineClient {
UploadOp::Delete(_) => {
upload_queue.num_inprogress_deletions += 1;
}
UploadOp::Barrier(sender) => {
sender.send_replace(());
continue;
}
UploadOp::Barrier(_) => {}
UploadOp::Shutdown => unreachable!("shutdown is intentionally never popped off"),
};
@@ -1905,7 +1902,33 @@ impl RemoteTimelineClient {
.await
.map_err(|e| anyhow::anyhow!(e))
}
unexpected @ UploadOp::Barrier(_) | unexpected @ UploadOp::Shutdown => {
UploadOp::Barrier(sender) => {
// Barrier operation needs to wait until all deletions are uploaded.
//
// There is an optimization in the deletion queue client that if generation is enabled for a tenant,
// we do not wait for the deletions to be flushed to the remote storage before we tell the user that
// the deletion is complete. This would cause problems for barrier semantics, as we expect all
// deletion to be persistent when the barrier is processed. For example, when we reload a timeline
// without restarting the pageserver (i.e., offload, detach/attach, detach_ancestor), the generation
// number is not bumped.
//
// Let's think about the following operation sequence:
//
// schedule deletion of layer A at generation 5
// schedule a barrier
// schedule a compaction that creates layer A at generation 5
// the actual deletion happens here
//
// We don't want the actual deletion happens after the barrier.
let res = self
.deletion_queue_client
.flush()
.await
.map_err(|e| anyhow::anyhow!(e));
sender.send_replace(());
res
}
unexpected @ UploadOp::Shutdown => {
// unreachable. Barrier operations are handled synchronously in
// launch_queued_tasks
warn!("unexpected {unexpected:?} operation in perform_upload_task");