## Problem
part of https://github.com/neondatabase/neon/issues/11067
My observation is that with the current value of settings, x86-v1
usually takes 30s, arm-v1 1m30s, x86-v2 1m, arm-v2 3m. But sometimes the
system could run too slow and cause test to timeout on arm with reldir
v2.
While I investigate what's going on and further improve the performance,
I'd like to set both of them to use the same test input, so that it
doesn't timeout and we don't abuse this test case as a performance test.
## Summary of changes
Use the same settings for both test cases.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Incoming requests often take the service lock, and sometimes even do
database transactions. That creates a risk that a rogue client can
starve the controller of the ability to do its primary job of
reconciling tenants to an available state.
## Summary of changes
* Use the `governor` crate to rate limit tenant requests at 10 requests
per second. This is ~10-100x lower than the worst "attack" we've seen
from a client bug. Admin APIs are not rate limited.
* Add a `storage_controller_http_request_rate_limited` histogram for
rate limited requests.
* Log a warning every 10 seconds for rate limited tenants.
The rate limiter is parametrized on TenantId, because the kinds of
client bug we're protecting against generally happen within tenant
scope, and the rates should be somewhat stable: we expect the global
rate of requests to increase as we do more work, but we do not expect
the rate of requests to one tenant to increase.
---------
Co-authored-by: John Spray <john@neon.tech>
## Problem
part of https://github.com/neondatabase/neon/issues/9516
## Summary of changes
Similar to the aux v2 migration, we persist the relv2 migration status
into index_part, so that even the config item is set to false, we will
still read from the v2 storage to avoid loss of data.
Note that only the two variants `None` and
`Some(RelSizeMigration::Migrating)` are used for now. We don't have full
migration implemented so it will never be set to
`RelSizeMigration::Migrated`.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
If a caller times out on safekeeper timeline deletion on a large
timeline, and waits a while before retrying, the deletion will not
progress while the retry is waiting. The net effect is very very slow
deletion as it only proceeds in 30 second bursts across 5 minute idle
periods.
Related: https://github.com/neondatabase/neon/issues/10265
## Summary of changes
- Run remote deletion in a background task
- Carry a watch::Receiver on the Timeline for other callers to join the
wait
- Restart deletion if the API is called again and the previous attempt
failed
## Problem
We want to support larger tenants (regarding logical database size,
number of transactions per second etc.) and should increase our test
coverage of OLTP transactions at larger scale.
## Summary of changes
Start a new benchmark that over time will add more OLTP tests at larger
scale.
This PR covers the first version and will be extended in further PRs.
Also fix some infrastructure:
- default for new connections and large tenants is to use connection
pooler pgbouncer, however our fixture always added
`statement_timeout=120` which is not compatible with pooler
[see](https://neon.tech/docs/connect/connection-errors#unsupported-startup-parameter)
- action to create branch timed out after 10 seconds and 10 retries but
for large tenants it can take longer so use increasing back-off for
retries
## Test run
https://github.com/neondatabase/neon/actions/runs/13593446706
## Problem
Preparation for https://github.com/neondatabase/neon/issues/10851
## Summary of changes
Add walproposer `safekeepers_generations` field which can be set by
prefixing `neon.safekeepers` GUC with `g#n:`. Non zero value (n) forces
walproposer to use generations. In particular, this also disables
implicit timeline creation as timeline will be created by storcon. Add
test checking this. Also add missing infra: `--safekeepers-generation`
flag to neon_local endpoint start + fix `--start-timeout` flag: it
existed but value wasn't used.
## Problem
In multi-character keys, the GIN index creates a CRC Hash of the first 3
bytes of the key.
The hash can have the first bit to be set or unset, needing to have a
consistent representation
of `char` across architectures for consistent results. GIN stores these
keys by their hashes
which determines the order in which the keys are obtained from the GIN
index.
By default, chars are signed in x86 and unsigned in arm, leading to
inconsistent behavior across different platform architectures. Adding
the `-fsigned-char` flag to the GCC compiler forces chars to be treated
as signed across platforms, ensuring the ordering in which the keys are
obtained consistent.
## Summary of changes
Added `-fsigned-char` to the `CFLAGS` to force GCC to use signed chars
across platforms.
Added a test to check this across platforms.
Fixes: https://github.com/neondatabase/cloud/issues/23199
## Problem
JWT tokens aren't in place, so all SK heartbeats fail. This is
equivalent to a wait before applying the PS heartbeats and makes things
more flaky.
## Summary of Changes
Add a flag that skips loading SKs from the db on start-up and at
runtime.
https://github.com/neondatabase/cloud/issues/23008
For TLS between proxy and compute, we are using an internally
provisioned CA to sign the compute certificates. This change ensures
that proxy will load them from a supplied env var pointing to the
correct file - this file and env var will be configured later, using a
kubernetes secret.
Control plane responds with a `server_name` field if and only if the
compute uses TLS. This server name is the name we use to validate the
certificate. Control plane still sends us the IP to connect to as well
(to support overlay IP).
To support this change, I'd had to split `host` and `host_addr` into
separate fields. Using `host_addr` and bypassing `lookup_addr` if
possible (which is what happens in production). `host` then is only used
for the TLS connection.
There's no blocker to merging this. The code paths will not be triggered
until the new control plane is deployed and the `enableTLS` compute flag
is enabled on a project.
## Problem
We intend for cplane to use the heatmap layer download API to warm up
timelines after unarchival. It's tricky for them to recurse in the
ancestors,
and the current implementation doesn't work well when unarchiving a
chain
of branches and warming them up.
## Summary of changes
* Add a `recurse` flag to the API. When the flag is set, the operation
recurses into the parent
timeline after the current one is done.
* Be resilient to warming up a chain of unarchived branches. Let's say
we unarchived `B` and `C` from
the `A -> B -> C` branch hierarchy. `B` got unarchived first. We
generated the unarchival heatmaps
and stash them in `A` and `B`. When `C` unarchived, it dropped it's
unarchival heatmap since `A` and `B`
already had one. If `C` needed layers from `A` and `B`, it was out of
luck. Now, when choosing whether
to keep an unarchival heatmap we look at its end LSN. If it's more
inclusive than what we currently have,
keep it.
Before this PR, re-attach and validate would log the same warning
```
calling control plane generation validation API failed
```
on retry errors.
This can be confusing.
This PR makes the message generically valid for any upcall and adds
additional tracing spans to capture context.
Along the way, clean up some copy-pasta variable naming.
refs
-
https://github.com/neondatabase/neon/issues/10381#issuecomment-2684755827
---------
Co-authored-by: Alexander Lakhin <alexander.lakhin@neon.tech>
## Problem
So far cumulative statistics have not been persisted when Neon scales to
zero (suspends endpoint).
With PR https://github.com/neondatabase/neon/pull/6560 the cumulative
statistics should now survive endpoint restarts and correctly trigger
the auto- vacuum and auto analyze maintenance
So far we did not have a testcase that validates that improvement in our
dev cloud environment with a real project.
## Summary of changes
Introduce testcase `test_cumulative_statistics_persistence`in the
benchmarking workflow running daily to verify:
- Verifies that the cumulative statistics are correctly persisted across
restarts.
- Cumulative statistics are important to persist across restarts because
they are used
- when auto-vacuum an auto-analyze trigger conditions are met.
- The test performs the following steps:
- Seed a new project using pgbench
- insert tuples that by itself are not enough to trigger auto-vacuum
- suspend the endpoint
- resume the endpoint
- insert additional tuples that by itself are not enough to trigger
auto-vacuum but in combination with the previous tuples are
- verify that autovacuum is triggered by the combination of tuples
inserted before and after endpoint suspension
## Test run
https://github.com/neondatabase/neon/actions/runs/13546879714/job/37860609089#step:6:282
## Problem
Yet another source of flakyness for
https://github.com/neondatabase/neon/issues/10517
## Summary of changes
The test scenario we want to create is that we have an image layer in
index_part and then overwrite it, so we have to ensure it gets persisted
in index_part by doing a force checkpoint.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
https://github.com/neondatabase/neon/pull/10241 added configuration
switch endpoint, but it didn't delete timeline if node was excluded.
## Summary of changes
Add separate /exclude API endpoint which similarly accepts membership
configuration where sk is supposed by be excluded. Implementation
deletes the timeline locally.
Some more small related tweaks:
- make mconf switch API PUT instead of POST as it is idempotent;
- return 409 if switch was refused instead of 200 with requested &
current;
- remove unused was_active flag from delete response;
- remove meaningless _force suffix from delete functions names;
- reuse timeline.rs delete_dir function in timelines_global_map instead
of its own copy.
part of https://github.com/neondatabase/neon/issues/9965
## Problem
I see a lot of timeout errors, which indicates that this test is too
slow. It seems that create relations are fast, but the subsequent
truncating step is slow.
## Summary of changes
Reduce number of relations for now, and investigate later.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
json_ctrl.rs is an obsolete attempt to have tests with fine control of
feeding messages into safekeeper superseded by desim framework.
## Summary of changes
Drop it.
## Problem
part of https://github.com/neondatabase/neon/issues/9114
## Summary of changes
Add the auto trigger for gc-compaction. It computes two values: L1 size
and L2 size. When L1 size >= initial trigger threshold, we will trigger
an initial gc-compaction. When l1_size / l2_size >=
gc_compaction_ratio_percent, we will trigger the "tiered" gc-compaction.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We have `test_perf_many_relations` but it only runs on remote clusters,
and we cannot directly modify tenant config. Therefore, I patched one of
the current tests to benchmark relv2 performance.
close https://github.com/neondatabase/neon/issues/9986
## Summary of changes
* Add `v1/v2` selector to `test_tx_abort_with_many_relations`.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
As part of https://github.com/neondatabase/neon/issues/8614 we need to
pass membership configurations between compute and safekeepers.
## Summary of changes
Add version 3 of the protocol carrying membership configurations.
Greeting message in both sides gets full conf, and other messages
generation number only. Use protocol bump to include other accumulated
changes:
- stop packing whole structs on the wire as is;
- make the tag u8 instead of u64;
- send all ints in network order;
- drop proposer_uuid, we can pass it in START_WAL_PUSH and it wasn't
much useful anyway.
Per message changes, apart from mconf:
- ProposerGreeting: tenant / timeline id is sent now as hex cstring.
Remove proto version, it is passed outside in START_WAL_PUSH. Remove
postgres timeline, it is unused. Reorder fields a bit.
- AcceptorGreeting: reorder fields
- VoteResponse: timeline_start_lsn is removed. It can be taken from
first member of term history, and later we won't need it at all when all
timelines will be explicitly created. Vote itself is u8 instead of u64.
- ProposerElected: timeline_start_lsn is removed for the same reasons.
- AppendRequest: epoch_start_lsn removed, it is known from term history
in ProposerElected.
Both compute and sk are able to talk v2 and v3 to make rollbacks (in
case we need them) easier; neon.safekeeper_proto_version GUC sets the
client version. v2 code can be dropped later.
So far empty conf is passed everywhere, future PRs will handle them.
To test, add param to some tests choosing proto version; we want to test
both 2 and 3 until we fully migrate.
ref https://github.com/neondatabase/neon/issues/10326
---------
Co-authored-by: Arthur Petukhovsky <petuhovskiy@yandex.ru>
We've seen some cases in production where a compute doesn't get a
response to a pageserver request for several minutes, or even more. We
haven't found the root cause for that yet, but whatever the reason is,
it seems overly optimistic to think that if the pageserver hasn't
responded for 2 minutes, we'd get a response if we just wait patiently a
little longer. More likely, the pageserver is dead or there's some kind
of a network glitch so that the TCP connection is dead, or at least
stuck for a long time. Either way, it's better to disconnect and
reconnect. I set the default timeout to 2 minutes, which should be
enough for any GetPage request under normal circumstances, even if the
pageserver has to download several layer files from remote storage.
Make the disconnect timeout configurable. Also make the "log interval",
after which we print a message to the log configurable, so that if you
change the disconnect timeout, you can set the log timeout
correspondingly. The default log interval is still 10 s. The new GUCs
are called "neon.pageserver_response_log_timeout" and
"neon.pageserver_response_disconnect_timeout".
Includes a basic test for the log and disconnect timeouts.
Implements issue #10857
## Problem
https://github.com/neondatabase/neon/pull/10788 introduced an API for
warming up attached locations
by downloading all layers in the heatmap. We intend to use it for
warming up timelines after unarchival too,
but it doesn't work. Any heatmap generated after the unarchival will not
include our timeline, so we've lost
all those layers.
## Summary of changes
Generate a cheeky heatmap on unarchival. It includes all the visible
layers.
Use that as the `PreviousHeatmap` which inputs into actual heatmap
generation.
Closes: https://github.com/neondatabase/neon/issues/10541
## Problem
We failed to detect https://github.com/neondatabase/neon/pull/10845
before merging, because the tests we run with a matrix of component
versions didn't include the ones that did live migrations.
## Summary of changes
- Do a live migration during the storage controller smoke test, since
this is a pretty core piece of functionality
- Apply a compat version matrix to the graceful cluster restart test,
since this is the functionality that we most urgently need to work
across versions to make deploys work.
I expect the first CI run of this to fail, because
https://github.com/neondatabase/neon/pull/10845 isn't merged yet.
There was a race condition with compute_ctl and the metric being
collected related to whether the neon extension had been updated or not.
compute_ctl will run `ALTER EXTENSION neon UPDATE` on compute start in
the postgres database.
Fixes: https://github.com/neondatabase/neon/issues/10932
Signed-off-by: Tristan Partin <tristan@neon.tech>
## Problem
Prefetch is performed locally, so different backers can request the same
pages form PS.
Such duplicated request increase load of page server and network
traffic.
Making prefetch global seems to be very difficult and undesirable,
because different queries can access chunks on different speed. Storing
prefetch chunks in LFC will not completely eliminate duplicates, but can
minimise such requests.
The problem with storing prefetch result in LFC is that in this case
page is not protected by share buffer lock.
So we will have to perform extra synchronisation at LFC side.
See:
https://neondb.slack.com/archives/C0875PUD0LC/p1736772890602029?thread_ts=1736762541.116949&cid=C0875PUD0LC
@MMeent implementation of prewarm:
See https://github.com/neondatabase/neon/pull/10312/
## Summary of changes
Use conditional variables to sycnhronize access to LFC entry.
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
## Problem
The storage controller treats durations in the tenant config as strings.
These are loaded from the db.
The pageserver maps these durations to a seconds only format and we
always get a mismatch compared
to what's in the db.
## Summary of changes
Treat durations as durations inside the storage controller and not as
strings.
Nothing changes in the cross service API's themselves or the way things
are stored in the db.
I also added some logging which I would have made the investigation a
10min job:
1. Reason for why the reconciliation was spawned
2. Location config diff between the observed and wanted states
## Problem
The interpreted SK <-> PS protocol does not guard against gaps (neither
does the Vanilla one, but that's beside the point).
## Summary of changes
Extend the protocol to include the start LSN of the PG WAL section from
which the records were interpreted.
Validation is enabled via a config flag on the pageserver and works as
follows:
**Case 1**: `raw_wal_start_lsn` is smaller than the requested LSN
There can't be gaps here, but we check that the shard received records
which it hasn't seen before.
**Case 2**: `raw_wal_start_lsn` is equal to the requested LSN
This is the happy case. No gap and nothing to check
**Case 3**: `raw_wal_start_lsn` is greater than the requested LSN
This is a gap.
To make Case 3 work I had to bend the protocol a bit.
We read record chunks of WAL which aren't record aligned and feed them
to the decoder.
The picture below shows a shard which subscribes at a position somewhere
within Record 2.
We already have a wal reader which is below that position so we wait to
catch up.
We read some wal in Read 1 (all of Record 1 and some of Record 2). The
new shard doesn't
need Record 1 (it has already processed it according to the starting
position), but we read
past it's starting position. When we do Read 2, we decode Record 2 and
ship it off to the shard,
but the starting position of Read 2 is greater than the starting
position the shard requested.
This looks like a gap.
To make it work, we extend the protocol to send an empty
`InterpretedWalRecords` to shards
if the WAL the records originated from ends the requested start
position. On the pageserver,
that just updates the tracking LSNs in memory (no-op really). This gives
us a workaround for
the fake gap.
As a drive by, make `InterpretedWalRecords::next_record_lsn` mandatory
in the application level definition.
It's always included.
Related: https://github.com/neondatabase/cloud/issues/23935
## Problem
Storage controller uses unsecure http for pageserver API.
Closes: https://github.com/neondatabase/cloud/issues/23734
Closes: https://github.com/neondatabase/cloud/issues/24091
## Summary of changes
- Add an optional `listen_https_port` field to storage controller's Node
state and its API (RegisterNode/ListNodes/etc).
- Allow updating `listen_https_port` on node registration to gradually
add https port for all nodes.
- Add `use_https_pageserver_api` CLI option to storage controller to
enable https.
- Pageserver doesn't support https for now and always reports
`https_port=None`. This will be addressed in follow-up PR.
ALTER SUBSCRIPTION requires AccessExclusive lock
which conflicts with iteration over pg_subscription when multiple
databases are present
and operations are applied concurrently.
Fix by explicitly locking pg_subscription
in the beginning of the transaction in each database.
## Problem
https://github.com/neondatabase/cloud/issues/24292
## Problem
Background heatmap uploads and downloads were blocking the ones done
manually by the test.
## Summary of changes
Disable Background heatmap uploads and downloads for the cold migration
test. The test does
them explicitly.
This PR does the following things:
* The initial heartbeat round blocks the storage controller from
becoming online again. If all safekeepers are unresponsive, this can
cause storage controller startup to be very slow. The original intent of
#10583 was that heartbeats don't affect normal functionality of the
storage controller. So add a short timeout to prevent it from impeding
storcon functionality.
* Fix the URL of the utilization endpoint.
* Don't send heartbeats to safekeepers which are decomissioned.
Part of https://github.com/neondatabase/neon/issues/9011
context: https://neondb.slack.com/archives/C033RQ5SPDH/p1739966807592589
## Problem
We lack an API for warming up attached locations based on the heatmap
contents.
This is problematic in two places:
1. If we manually migrate and cut over while the secondary is still cold
2. When we re-attach a previously offloaded tenant
## Summary of changes
https://github.com/neondatabase/neon/pull/10597 made heatmap generation
additive
across migrations, so we won't clobber it a after a cold migration. This
allows us to implement:
1. An endpoint for downloading all missing heatmap layers on the
pageserver:
`/v1/tenant/:tenant_shard_id/timeline/:timeline_id/download_heatmap_layers`.
Only one such operation per timeline is allowed at any given time. The
granularity is tenant shard.
2. An endpoint to the storage controller to trigger the downloads on the
pageserver:
`/v1/tenant/:tenant_shard_id/timeline/:timeline_id/download_heatmap_layers`.
This works both at
tenant and tenant shard level. If an unsharded tenant id is provided,
the operation is started on
all shards, otherwise only the specified shard.
3. A storcon cli command. Again, tenant and tenant-shard level
granularities are supported.
Cplane will call into storcon and trigger the downloads for all shards.
When we want to rescue a migration, we will use storcon cli targeting
the specific tenant shard.
Related: https://github.com/neondatabase/neon/issues/10541
## Problem
ref https://github.com/neondatabase/neon/issues/10517
## Summary of changes
For some reasons the job split algorithm decides to have different image
coverage range for two compactions before/after restart. So we remove
the subcompaction key range and let it generate an image covering the
full range, which should make the test more stable.
Also slightly tuned the logging span.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
This reverts commit 443c8d0b4b.
## Problem
We observe a massive amount of compaction errors.
## Summary of changes
If the tenant did not write any L1 layers (i.e., they accumulate L0
layers where number of them is below L0 threshold), image creation will
always fail. Therefore, it's not correct to simply use the
disk_consistent_lsn or L0/L1 boundary for the image creation.
## Problem
Tests with mixed versions of binaries always pick up new versions if
services are started using `neon_local`.
## Summary of changes
- Set `neon_local_binpath` along with `neon_binpath` and
`pg_distrib_dir` for tests with mixed versions
## Problem
Test fails when comparing the first WAL segment because the system id in
the segment header is different. The system id is not consistently set
correctly since segments are usually inited on the safekeeper sync step
with sysid 0.
## Summary of Chnages
Compare timeline digests instead. This skips the header.
Closes https://github.com/neondatabase/neon/issues/10596
## Problem
Part of https://github.com/neondatabase/neon/issues/9516
## Summary of changes
This patch adds the support for storing reldir in the sparse keyspace.
All logic are guarded with the `rel_size_v2_enabled` flag, so if it's
set to false, the code path is exactly the same as what's currently in
prod.
Note that we did not persist the `rel_size_v2_enabled` flag and the
logic around it will be implemented in the next patch. (i.e., what if we
enabled it, restart the pageserver, and then it gets set to false? we
should still read from v2 using the rel_size_v2_migration_status in the
index_part). The persistence logic I'll implement in the next patch will
disallow switching from v2->v1 via config item.
I also refactored the metrics so that it can work with the new reldir
store. However, this metric is not correctly computed for reldirs (see
the comments) before. With the refactor, the value will be computed only
when we have an initial value for the reldir size. The refactor keeps
the incorrectness of the computation when there are more than 1
database.
For the tests, we currently run all the tests with v2, and I'll set it
to false and add some v2-specific tests before merging, probably also
v1->v2 migration tests.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
See https://github.com/neondatabase/neon/issues/10755
Random access pattern of pgbench leaves sparse chunks, which makes the
on-disk size of file.cache unpredictable.
## Summary of changes
Perform seqscan to fill LFC chunks with data so that on-disk file size
included size of table.
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
There was a typo in the name of the utilization endpoint URL, fix it.
Also, ensure that the heartbeat mechanism actually works.
Related: #10583, #10429
Part of #9011
## Problem
The test is flaky: WAL in remote storage appears to be corrupted. One of
hypotheses so far is that corruption is the result of local fs
implementation being non atomic, and safekeepers may concurrently PUT
the same segment. That's dubious though because by looking at local_fs
impl I'd expect then early EOF on segment read rather then observed
zeros in test failures, but other directions seem even less probable.
## Summary of changes
Let's add s3 backend as well and see if it is also flaky. Also add some
more logging around segments uploads.
ref https://github.com/neondatabase/neon/issues/10761
## Problem
This test occasionally fails while the test teardown tries to do a
graceful shutdown, because the test has quickly written lots of data
into the pageserver.
Closes: #10654
## Summary of changes
- Call `post_checks` at the end of `test_isolation`, as we already do
for test_pg_regress -- this improves our detection of issues, and as a
nice side effect flushes the pageserver.
- Ignore pg_notify files when validating state at end of test, these are
not expected to be the same
## Problem
In #10752 I used an overly-strict regex that only ignored error on a
particular key.
## Summary of changes
- Drop key from regex so it matches all such errors
## Problem
Previously, when cutting over to cold secondary locations,
we would clobber the previous, good, heatmap with a cold one.
This is because heatmap generation used to include only resident layers.
Once this merges, we can add an endpoint which triggers full heatmap
hydration on attached locations to heal cold migrations.
## Summary of changes
With this patch, heatmap generation becomes additive. If we have a
heatmap from when this location was secondary, the new uploaded heatmap
will be the result of a reconciliation between the old one and the on
disk resident layers.
More concretely, when we have the previous heatmap:
1. Filter the previous heatmap and keep layers that are (a) present
in the current layer map, (b) visible, (c) not resident. Call this set
of layers `visible_non_resident`.
2. From the layer map, select all layers that are resident and visible.
Call this set of layers `resident`.
3. The new heatmap is the result of merging the two disjoint sets.
Related https://github.com/neondatabase/neon/issues/10541
## Problem
We expose `latest_gc_cutoff` in our API, and callers understandably were
using that to validate LSNs for branch creation. However, this is _not_
the true GC cutoff from a user's point of view: it's just the point at
which we last actually did GC. The actual cutoff used when validating
branch creations and page_service reads is the min() of latest_gc_cutoff
and the planned GC lsn in GcInfo.
Closes: https://github.com/neondatabase/neon/issues/10639
## Summary of changes
- Expose the more useful min() of GC cutoffs as `gc_cutoff_lsn` in the
API, so that the most obviously named field is really the one people
should use.
- Retain the ability to read the LSN at which GC was actually done, in
an `applied_gc_cutoff_lsn` field.
- Internally rename `latest_gc_cutoff_lsn` to `applied_gc_cutoff_lsn`
("latest" was a confusing name, as the value in GcInfo is more up to
date in terms of what a user experiences)
- Temporarily preserve the old `latest_gc_cutoff_lsn` field for compat
with control plane until we update it to use the new field.
---------
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
