## Problem
I suspect that the pageservers get stuck on receiving broker updates.
## Summary of changes
This is a an opportunistic (staging only) patch that resets the
susbscription
stream if it's been idle for a while. This won't go to prod in this
form.
I'll revert or update it before Friday.
## Problem
Better investigate memory usage during backpressure
## Summary of changes
Print open layer size if backpressure is activated
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Ancestor detach from a previously detached parent when there were no
writes panics since it tries to upload the tombstone layer twice.
## Summary of Changes
If we're gonna copy the tombstone from the ancestor, don't bother
creating it.
Fixes https://github.com/neondatabase/neon/issues/12458
## TLDR
This PR is a no-op. The changes are disabled by default.
## Problem
I. Currently we don't have a way to detect disk I/O failures from WAL
operations.
II.
We observe that the offloader fails to upload a segment due to race
conditions on XLOG SWITCH and PG start streaming WALs. wal_backup task
continously failing to upload a full segment while the segment remains
partial on the disk.
The consequence is that commit_lsn for all SKs move forward but
backup_lsn stays the same. Then, all SKs run out of disk space.
III.
We have discovered SK bugs where the WAL offload owner cannot keep up
with WAL backup/upload to S3, which results in an unbounded accumulation
of WAL segment files on the Safekeeper's disk until the disk becomes
full. This is a somewhat dangerous operation that is hard to recover
from because the Safekeeper cannot write its control files when it is
out of disk space. There are actually 2 problems here:
1. A single problematic timeline can take over the entire disk for the
SK
2. Once out of disk, it's difficult to recover SK
IV.
Neon reports certain storage errors as "critical" errors using a marco,
which will increment a counter/metric that can be used to raise alerts.
However, this metric isn't sliced by tenant and/or timeline today. We
need the tenant/timeline dimension to better respond to incidents and
for blast radius analysis.
## Summary of changes
I.
The PR adds a `safekeeper_wal_disk_io_errors ` which is incremented when
SK fails to create or flush WALs.
II.
To mitigate this issue, we will re-elect a new offloader if the current
offloader is lagging behind too much.
Each SK makes the decision locally but they are aware of each other's
commit and backup lsns.
The new algorithm is
- determine_offloader will pick a SK. say SK-1.
- Each SK checks
-- if commit_lsn - back_lsn > threshold,
-- -- remove SK-1 from the candidate and call determine_offloader again.
SK-1 will step down and all SKs will elect the same leader again.
After the backup is caught up, the leader will become SK-1 again.
This also helps when SK-1 is slow to backup.
I'll set the reelect backup lag to 4 GB later. Setting to 128 MB in dev
to trigger the code more frequently.
III.
This change addresses problem no. 1 by having the Safekeeper perform a
timeline disk utilization check check when processing WAL proposal
messages from Postgres/compute. The Safekeeper now rejects the WAL
proposal message, effectively stops writing more WAL for the timeline to
disk, if the existing WAL files for the timeline on the SK disk exceeds
a certain size (the default threshold is 100GB). The disk utilization is
calculated based on a `last_removed_segno` variable tracked by the
background task removing WAL files, which produces an accurate and
conservative estimate (>= than actual disk usage) of the actual disk
usage.
IV.
* Add a new metric `hadron_critical_storage_event_count` that has the
`tenant_shard_id` and `timeline_id` as dimensions.
* Modified the `crtitical!` marco to include tenant_id and timeline_id
as additional arguments and adapted existing call sites to populate the
tenant shard and timeline ID fields. The `critical!` marco invocation
now increments the `hadron_critical_storage_event_count` with the extra
dimensions. (In SK there isn't the notion of a tenant-shard, so just the
tenant ID is recorded in lieu of tenant shard ID.)
I considered adding a separate marco to avoid merge conflicts, but I
think in this case (detecting critical errors) conflicts are probably
more desirable so that we can be aware whenever Neon adds another
`critical!` invocation in their code.
---------
Co-authored-by: Chen Luo <chen.luo@databricks.com>
Co-authored-by: Haoyu Huang <haoyu.huang@databricks.com>
Co-authored-by: William Huang <william.huang@databricks.com>
## Problem
The billing team wants to change the billing events pipeline and use a
common events format in S3 buckets across different event producers.
## Summary of changes
Change the events storage format for billing events from JSON to NDJSON.
Also partition files by hours, rather than days.
Resolves: https://github.com/neondatabase/cloud/issues/29995
Don't print errors like:
```
Compaction failed 1 times, retrying in 2s: Failed to offload timeline: Unexpected offload error: Timeline deletion is already in progress
```
Print it at info log level instead.
https://github.com/neondatabase/cloud/issues/30666
Not sure how verbose we want this to be in production, but for now,
more is better.
This shows that many tests are failing with errors like these:
PG:2025-07-01 23:02:34.311 GMT [1456523] LOG: [COMMUNICATOR] send_process_get_rel_size_request: got error status: NotFound, message: "Read error", details: [], metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Tue, 01 Jul 2025 23:02:34 GMT"} }, retrying
I haven't debugged why that is yet. Did the compute make a bogus request?
## Problem
Part of #11813
## Summary of changes
* Compute tenant remote size in the housekeeping loop.
* Add a new `TenantFeatureResolver` struct to cache the tenant-specific
properties.
* Evaluate feature flag based on the remote size.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
close https://github.com/neondatabase/neon/issues/11528
## Summary of changes
Gives us better observability of compaction progress.
- Image creation: num of partition processed / total partition
- Gc-compaction: index of the in the queue / total items for a full
compaction
- Shard ancestor compaction: layers to rewrite / total layers
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
L0 compaction currently holds the read lock for a long region while it
doesn't need to.
## Summary of changes
This patch reduces the one long contention region into 2 short ones:
gather the layers to compact at the beginning, and several short read
locks when querying the image coverage.
Co-Authored-By: Chen Luo
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
If a hardlink operation inside `detach_ancestor` fails due to the layer
already existing, we delete the layer to make sure the source is one we
know about, and then retry.
But we deleted the wrong file, namely, the one we wanted to use as the
source of the hardlink. As a result, the follow up hard link operation
failed. Our PR corrects this mistake.
## Problem
The gRPC API does not provide LSN leases.
## Summary of changes
* Add LSN lease support to the gRPC API.
* Use gRPC LSN leases for static computes with `grpc://` connstrings.
* Move `PageserverProtocol` into the `compute_api::spec` module and
reuse it.
## Problem
Location config changes can currently result in changes to the shard
identity. Such changes will cause data corruption, as seen with #12217.
Resolves#12227.
Requires #12377.
## Summary of changes
Assert that the shard identity does not change on location config
updates and on (re)attach.
This is currently asserted with `critical!`, in case it misfires in
production. Later, we should reject such requests with an error and turn
this into a proper assertion.
Implicit mapping to an `anyhow::Error` when we do `?` is discouraged
because tooling to find those places isn't great.
As a drive-by, also make SplitImageLayerWriter::new infallible and sync.
I think we should also make ImageLayerWriter::new completely lazy,
then `BatchLayerWriter:new` infallible and async.
## Problem
Similarly to #12217, the following endpoints may result in a stripe size
mismatch between the storage controller and Pageserver if an unsharded
tenant has a different stripe size set than the default. This can lead
to data corruption if the tenant is later manually split without
specifying an explicit stripe size, since the storage controller and
Pageserver will apply different defaults. This commonly happens with
tenants that were created before the default stripe size was changed
from 32k to 2k.
* `PUT /v1/tenant/config`
* `PATCH /v1/tenant/config`
These endpoints are no longer in regular production use (they were used
when cplane still managed Pageserver directly), but can still be called
manually or by tests.
## Summary of changes
Retain the current shard parameters when updating the location config in
`PUT | PATCH /v1/tenant/config`.
Also opportunistically derive `Copy` for `ShardParameters`.
- avoid panic by checking for Ok(None) response from
tonic::Streaming::message() instead of just using unwrap()
- There was a race condition, if the caller sent the message, but the
receiver task concurrently received Ok(None) indicating the stream
was closed. (I didn't see that in action, but I think it could happen
by reading the code)
After reading the code a few times, I didn't quite understand what it
was, to be honest, or how it was going to be used. Remove it now to
reduce noise, but we can resurrect it from git history if we need it
in the future.
Add a new 'pageserver_connection_info' field in the compute spec. It
replaces the old 'pageserver_connstring' field with a more complicated
struct that includes both libpq and grpc URLs, for each shard (or only
one of the the URLs, depending on the configuration). It also includes
a flag suggesting which one to use; compute_ctl now uses it to decide
which protocol to use for the basebackup.
This is compatible with everything that's in production, because the
control plane never used the 'pageserver_connstring' field. That was
added a long time ago with the idea that it would replace the code
that digs the 'neon.pageserver_connstring' GUC from the list of
Postgres settings, but we never got around to do that in the control
plane. Hence, it was only used with neon_local. But the plan now is to
pass the 'pageserver_connection_info' from the control plane, and once
that's fully deployed everywhere, the code to parse
'neon.pageserver_connstring' in compute_ctl can be removed.
The 'grpc' flag on an endpoint in endpoint config is now more of a
suggestion. Compute_ctl gets both URLs, so it can choose to use libpq
or grpc as it wishes. It currently always obeys the 'prefer_grpc' flag
that's part of the connection info though. Postgres however uses grpc
iff the new rust-based communicator is enabled.
TODO/plan for the control plane:
- Start to pass `pageserver_connection_info` in the spec file.
- Also keep the current `neon.pageserver_connstring` setting for now,
for backwards compatibility with old computes
After that, the `pageserver_connection_info.prefer_grpc` flag in the
spec file can be used to control whether compute_ctl uses grpc or
libpq. The actual compute's grpc usage will be controlled by the
`neon.enable_new_communicator` GUC. It can be set separately from
'prefer_grpc'.
Later:
- Once all old computes are gone, remove the code to pass
`neon.pageserver_connstring`
## Problem
`compute_ctl` should support gRPC base backups.
Requires #12111.
Requires #12243.
Touches #11926.
## Summary of changes
Support `grpc://` connstrings for `compute_ctl` base backups.
## Problem
The problem has been well described in already-commited PR #11853.
tl;dr: BufferedWriter is sensitive to cancellation, which the previous
approach was not.
The write path was most affected (ingest & compaction), which was mostly
fixed in #11853:
it introduced `PutError` and mapped instances of `PutError` that were
due to cancellation of underlying buffered writer into
`CreateImageLayersError::Cancelled`.
However, there is a long tail of remaining errors that weren't caught by
#11853 that result in `CompactionError::Other`s, which we log with great
noise.
## Solution
The stack trace logging for CompactionError::Other added in #11853
allows us to chop away at that long tail using the following pattern:
- look at the stack trace
- from leaf up, identify the place where we incorrectly map from the
distinguished variant X indicating cancellation to an `anyhow::Error`
- follow that anyhow further up, ensuring it stays the same anyhow all
the way up in the `CompactionError::Other`
- since it stayed one anyhow chain all the way up, root_cause() will
yield us X
- so, in `log_compaction_error`, add an additional `downcast_ref` check
for X
This PR specifically adds checks for
- the flush task cancelling (FlushTaskError, BlobWriterError)
- opening of the layer writer (GateError)
That should cover all the reports in issues
- https://github.com/neondatabase/cloud/issues/29434
- https://github.com/neondatabase/neon/issues/12162
## Refs
- follow-up to #11853
- fixup of / fixes https://github.com/neondatabase/neon/issues/11762
- fixes https://github.com/neondatabase/neon/issues/12162
- refs https://github.com/neondatabase/cloud/issues/29434
We don't have cancellation support for timeline deletions. In other
words, timeline deletion might still go on in an older generation while
we are attaching it in a newer generation already, because the
cancellation simply hasn't reached the deletion code.
This has caused us to hit a situation with offloaded timelines in which
the timeline was in an unrecoverable state: always returning an accepted
response, but never a 404 like it should be.
The detailed description can be found in
[here](https://github.com/neondatabase/cloud/issues/30406#issuecomment-3008667859)
(private repo link).
TLDR:
1. we ask to delete timeline on old pageserver/generation, starts
process in background
2. the storcon migrates the tenant to a different pageserver.
- during attach, the pageserver still finds an index part, so it adds it
to `offloaded_timelines`
4. the timeline deletion finishes, removing the index part in S3
5. there is a retry of the timeline deletion endpoint, sent to the new
pageserver location. it is bound to fail however:
- as the index part is gone, we print `Timeline already deleted in
remote storage`.
- the problem is that we then return an accepted response code, and not
a 404.
- this confuses the code calling us. it thinks the timeline is not
deleted, so keeps retrying.
- this state never gets recovered from until a reset/detach, because of
the `offloaded_timelines` entry staying there.
This is where this PR fixes things: if no index part can be found, we
can safely assume that the timeline is gone in S3 (it's the last thing
to be deleted), so we can remove it from `offloaded_timelines` and
trigger a reupload of the manifest. Subsequent retries will pick that
up.
Why not improve the cancellation support? It is a more disruptive code
change, that might have its own risks. So we don't do it for now.
Fixes https://github.com/neondatabase/cloud/issues/30406
