## Problem
When generations were new, these messages were an important way of
noticing if something unexpected was going on. We found some real issues
when investigating tests that unexpectedly tripped them.
At time has gone on, this code is now pretty battle-tested, and as we do
more live migrations etc, it's fairly normal to see the occasional
message from a node with a stale generation.
At this point the cognitive load on developers to selectively allow-list
these logs outweighs the benefit of having them at warn severity.
Closes: https://github.com/neondatabase/neon/issues/8080
## Summary of changes
- Downgrade "Dropped remote consistent LSN updates" and "Dropping stale
deletions" messages to INFO
- Remove all the allow-list entries for these logs.
We've stored metadata as bytes within the `index_part.json` for
long fixed reasons. #7693 added support for reading out normal json
serialization of the `TimelineMetadata`.
Change the serialization to only write `TimelineMetadata` as json for
going forward, keeping the backward compatibility to reading the
metadata as bytes. Because of failure to include `alias = "metadata"` in
#7693, one more follow-up is required to make the switch from the old
name to `"metadata": <json>`, but that affects only the field name in
serialized format.
In documentation and naming, an effort is made to add enough warning
signs around TimelineMetadata so that it will receive no changes in the
future. We can add those fields to `IndexPart` directly instead.
Additionally, the path to cleaning up `metadata.rs` is documented in the
`metadata.rs` module comment. If we must extend `TimelineMetadata`
before that, the duplication suggested in [review comment] is the way to
go.
[review comment]:
https://github.com/neondatabase/neon/pull/7699#pullrequestreview-2107081558
- Rename "filename" types which no longer map directly to a filename
(LayerFileName -> LayerName)
- Add a -v1- part to local layer paths to smooth the path to future
updates (we anticipate a -v2- that uses checksums later)
- Rename methods that refer to the string-ized version of a LayerName to
no longer be called "filename"
- Refactor reconcile() function to use a LocalLayerFileMetadata type
that includes the local path, rather than carrying local path separately
in a tuple and unwrap()'ing it later.
## Problem
Part of the legacy (but current) compaction algorithm is to find a stack
of overlapping delta layers which will be turned
into an image layer. This operation is exponential in terms of the
number of matching layers and we do it roughly every 20 seconds.
## Summary of changes
Only check if a new image layer is required if we've ingested a certain
amount of WAL since the last check.
The amount of wal is expressed in terms of multiples of checkpoint
distance, with the intuition being that
that there's little point doing the check if we only have two new L1
layers (not enough to create a new image).
Not a user-facing change, but can break any existing `.neon` directories
created by neon_local, as the name of the database used by the storage
controller changes.
This PR changes all the locations apart from the path of
`control_plane/attachment_service` (waiting for an opportune moment to
do that one, because it's the most conflict-ish wrt ongoing PRs like
#6676 )
The walproposer pretends to be a walsender in many ways. It has a
WalSnd slot, it claims to be a walsender by calling
MarkPostmasterChildWalSender() etc. But one different to real
walsenders was that the postmaster still treated it as a bgworker
rather than a walsender. The difference is that at shutdown,
walsenders are not killed until the very end, after the checkpointer
process has written the shutdown checkpoint and exited.
As a result, the walproposer always got killed before the shutdown
checkpoint was written, so the shutdown checkpoint never made it to
safekeepers. That's fine in principle, we don't require a clean
shutdown after all. But it also feels a bit silly not to stream the
shutdown checkpoint. It could be useful for initializing hot standby
mode in a read replica, for example.
Change postmaster to treat background workers that have called
MarkPostmasterChildWalSender() as walsenders. That unfortunately
requires another small change in postgres core.
After doing that, walproposers stay alive longer. However, it also
means that the checkpointer will wait for the walproposer to switch to
WALSNDSTATE_STOPPING state, when the checkpointer sends the
PROCSIG_WALSND_INIT_STOPPING signal. We don't have the machinery in
walproposer to receive and handle that signal reliably. Instead, we
mark walproposer as being in WALSNDSTATE_STOPPING always.
In commit 568f91420a, I assumed that shutdown will wait for all the
remaining WAL to be streamed to safekeepers, but before this commit
that was not true, and the test became flaky. This should make it
stable again.
Some tests wrongly assumed that no WAL could have been written between
pg_current_wal_flush_lsn and quick pg stop after it. Fix them by introducing
flush_ep_to_pageserver which first stops the endpoint and then waits till all
committed WAL reaches the pageserver.
In passing extract safekeeper http client to its own module.
Extracted from https://github.com/neondatabase/neon/pull/6953
Part of https://github.com/neondatabase/neon/issues/5899
Core Change
-----------
In #6953, we need the ability to scan the log _after_ a specific line
and ignore anything before that line.
This PR changes `log_contains` to returns a tuple of `(matching line,
cursor)`.
Hand that cursor to a subsequent `log_contains` call to search the log
for the next occurrence of the pattern.
Other Changes
-------------
- Inspect all the callsites of `log_contains` to handle the new tuple
return type.
- Above inspection unveiled many callers aren't using `assert
log_contains(...) is not None` but some weaker version of the code that
breaks if `log_contains` ever returns a not-None but falsy value. Fix
that.
- Above changes unveiled that `test_remote_storage_upload_queue_retries`
was using `wait_until` incorrectly; after fixing the usage, I had to
raise the `wait_until` timeout. So, maybe this will fix its flakiness.
This is a precursor to:
- https://github.com/neondatabase/neon/pull/6185
While that PR contains big changes to neon_local and attachment_service,
this PR contains a few unrelated standalone changes generated while
working on that branch:
- Fix restarting a pageserver when it contains multiple shards for the
same tenant
- When using location_config api to attach a tenant, create its
timelines dir
- Update test paths where generations were previously optional to make
them always-on: this avoids tests having to spuriously assert that
attachment_service is not None in order to make the linter happy.
- Add a TenantShardId python implementation for subsequent use in test
helpers that will be made shard-aware
- Teach scrubber to read across shards when checking for layer
existence: this is a refactor to track the list of existent layers at
tenant-level rather than locally to each timeline. This is a precursor
to testing shard splitting.
## Problem
Some existing tests are written in a way that's incompatible with tenant
generations.
## Summary of changes
Update all the tests that need updating: this is things like calling
through the NeonPageserver.tenant_attach helper to get a generation
number, instead of calling directly into the pageserver API. There are
various more subtle cases.
If there are too many L0 layers before compaction, the compaction
process becomes slow because of slow `Timeline::get`. As a result of the
slowdown, the pageserver will generate even more L0 layers for the next
iteration, further exacerbating the slow performance.
Change to perform L0 -> L1 compaction before creating new images. The
simple change speeds up compaction time and `Timeline::get` to 5x.
`Timeline::get` is faster on top of L1 layers.
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
fixes https://github.com/neondatabase/neon/issues/5878
obsoletes https://github.com/neondatabase/neon/issues/5879
Before this PR, it could happen that `load_layer_map` schedules removal
of the future
image layer. Then a later compaction run could re-create the same image
layer, scheduling a PUT.
Due to lack of an upload queue barrier, the PUT and DELETE could be
re-ordered.
The result was IndexPart referencing a non-existent object.
## Summary of changes
* Add support to `pagectl` / Python tests to decode `IndexPart`
* Rust
* new `pagectl` Subcommand
* `IndexPart::{from,to}_s3_bytes()` methods to internalize knowledge
about encoding of `IndexPart`
* Python
* new `NeonCli` subclass
* Add regression test
* Rust
* Ability to force repartitioning; required to ensure image layer
creation at last_record_lsn
* Python
* The regression test.
* Fix the issue
* Insert an `UploadOp::Barrier` after scheduling the deletions.
