## Problem
https://github.com/neondatabase/neon/pull/8852 introduced a new nullable
column for the `nodes` table: `availability_zone_id`
## Summary of changes
* Make neon local and the test suite always provide an az id
* Make the az id field in the ps registration request mandatory
* Migrate the column to non-nullable and adjust in memory state
accordingly
* Remove the code that was used to populate the az id for pre-existing
nodes
This PR simplifies the pageserver configuration parsing as follows:
* introduce the `pageserver_api::config::ConfigToml` type
* implement `Default` for `ConfigToml`
* use serde derive to do the brain-dead leg-work of processing the toml
document
* use `serde(default)` to fill in default values
* in `pageserver` crate:
* use `toml_edit` to deserialize the pageserver.toml string into a
`ConfigToml`
* `PageServerConfig::parse_and_validate` then
* consumes the `ConfigToml`
* destructures it exhaustively into its constituent fields
* constructs the `PageServerConfig`
The rules are:
* in `ConfigToml`, use `deny_unknown_fields` everywhere
* static default values go in `pageserver_api`
* if there cannot be a static default value (e.g. which default IO
engine to use, because it depends on the runtime), make the field in
`ConfigToml` an `Option`
* if runtime-augmentation of a value is needed, do that in
`parse_and_validate`
* a good example is `virtual_file_io_engine` or `l0_flush`, both of
which need to execute code to determine the effective value in
`PageServerConf`
The benefits:
* massive amount of brain-dead repetitive code can be deleted
* "unused variable" compile-time errors when removing a config value,
due to the exhaustive destructuring in `parse_and_validate`
* compile-time errors guide you when adding a new config field
Drawbacks:
* serde derive is sometimes a bit too magical
* `deny_unknown_fields` is easy to miss
Future Work / Benefits:
* make `neon_local` use `pageserver_api` to construct `ConfigToml` and
write it to `pageserver.toml`
* This provides more type safety / coompile-time errors than the current
approach.
### Refs
Fixes#3682
### Future Work
* `remote_storage` deser doesn't reject unknown fields
https://github.com/neondatabase/neon/issues/8915
* clean up `libs/pageserver_api/src/config.rs` further
* break up into multiple files, at least for tenant config
* move `models` as appropriate / refine distinction between config and
API models / be explicit about when it's the same
* use `pub(crate)` visibility on `mod defaults` to detect stale values
Set the field to optional, otherwise there will be decode errors when
newer version of the storage controller receives the JSON from older
version of the pageservers.
Signed-off-by: Alex Chi Z <chi@neon.tech>
It's better to reject invalid keys on the write path than storing it and
panic-ing the pageserver.
https://github.com/neondatabase/neon/issues/8636
## Summary of changes
If a key cannot be represented using i128, we don't allow writing that
key into the pageserver.
There are two versions of the check valid function: the normal one that
simply rejects i128 keys, and the stronger one that rejects all keys
that we don't support.
The current behavior when a key gets rejected is that safekeeper will
keep retrying streaming that key to the pageserver. And once such key
gets written, no new computes can be started. Therefore, there could be
a large amount of pageserver warnings if a key cannot be ingested. To
validate this behavior by yourself, the reviewer can (1) use the
stronger version of the valid check (2) run the following SQL.
```
set neon.regress_test_mode = true;
CREATE TABLESPACE regress_tblspace LOCATION '/Users/skyzh/Work/neon-test/tablespace';
CREATE SCHEMA testschema;
CREATE TABLE testschema.foo (i int) TABLESPACE regress_tblspace;
insert into testschema.foo values (1), (2), (3);
```
For now, I'd like to merge the patch with only rejecting non-i128 keys.
It's still unknown whether the stronger version covers all the cases
that basebackup doesn't support. Furthermore, the behavior of rejecting
a key will produce large amounts of warnings due to safekeeper retry.
Therefore, I'd like to reject the minimum set of keys that we don't
support (i128 ones) for now. (well, erroring out is better than panic on
`to_compact_key`)
The next step is to fix the safekeeper behavior (i.e., on such key
rejections, stop streaming WAL), so that we can properly stop writing.
An alternative solution is to simply drop these keys on the write path.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
In proxy I switched to a leaky-bucket impl using the GCRA algorithm. I
figured I could share the code with pageserver and remove the
leaky_bucket crate dependency with some very basic tokio timers and
queues for fairness.
The underlying algorithm should be fairly clear how it works from the
comments I have left in the code.
---
In benchmarking pageserver, @problame found that the new implementation
fixes a getpage throughput discontinuity in pageserver under the
`pagebench get-page-latest-lsn` benchmark with the clickbench dataset
(`test_perf_olap.py`).
The discontinuity is that for any of `--num-clients={2,3,4}`, getpage
throughput remains 10k.
With `--num-clients=5` and greater, getpage throughput then jumps to the
configured 20k rate limit.
With the changes in this PR, the discontinuity is gone, and we scale
throughput linearly to `--num-clients` until the configured rate limit.
More context in
https://github.com/neondatabase/cloud/issues/16886#issuecomment-2315257641.
closes https://github.com/neondatabase/cloud/issues/16886
---------
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
## Problem
In order to build AZ aware scheduling, the storage controller needs to
know what AZ pageservers are in.
Related https://github.com/neondatabase/neon/issues/8848
## Summary of changes
This patch set adds a new nullable column to the `nodes` table:
`availability_zone_id`. The node registration
request is extended to include the AZ id (pageservers already have this
in their `metadata.json` file).
If the node is already registered, then we update the persistent and
in-memory state with the provided AZ.
Otherwise, we add the node with the AZ to begin with.
A couple assumptions are made here:
1. Pageserver AZ ids are stable
2. AZ ids do not change over time
Once all pageservers have a configured AZ, we can remove the optionals
in the code and make the database column not nullable.
Protocol version 2 has been the default for a while now, and we no
longer have any computes running in production that used protocol
version 1. This completes the migration by removing support for v1 in
both the pageserver and the compute.
See issue #6211.
Part of #8002, the final big PR in the batch.
## Summary of changes
This pull request uses the new split layer writer in the gc-compaction.
* It changes how layers are split. Previously, we split layers based on
the original split point, but this creates too many layers
(test_gc_feedback has one key per layer).
* Therefore, we first verify if the layer map can be processed by the
current algorithm (See https://github.com/neondatabase/neon/pull/8191,
it's basically the same check)
* On that, we proceed with the compaction. This way, it creates a large
enough layer close to the target layer size.
* Added a new set of functions `with_discard` in the split layer writer.
This helps us skip layers if we are going to produce the same persistent
key.
* The delta writer will keep the updates of the same key in a single
file. This might create a super large layer, but we can optimize it
later.
* The split layer writer is used in the gc-compaction algorithm, and it
will split layers based on size.
* Fix the image layer summary block encoded the wrong key range.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Arpad Müller <arpad-m@users.noreply.github.com>
Co-authored-by: Christian Schwarz <christian@neon.tech>
This PR:
* Implements the rule that archived timelines require all of their
children to be archived as well, as specified in the RFC. There is no
fancy locking mechanism though, so the precondition can still be broken.
As a TODO for later, we still allow unarchiving timelines with archived
parents.
* Adds an `is_archived` flag to `TimelineInfo`
* Adds timeline_archival_config to `PageserverHttpClient`
* Adds a new `test_timeline_archive` test, loosely based on
`test_timeline_delete`
Part of #8088
## Problem
Previously, the controller only used the shard counts for scheduling.
This works well when hosting only many-sharded tenants, but works much
less well when hosting single-sharded tenants that have a greater
deviation in size-per-shard.
Closes: https://github.com/neondatabase/neon/issues/7798
## Summary of changes
- Instead of UtilizationScore, carry the full PageserverUtilization
through into the Scheduler.
- Use the PageserverUtilization::score() instead of shard count when
ordering nodes in scheduling.
Q: Why did test_sharding_split_smoke need updating in this PR?
A: There's an interesting side effect during shard splits: because we do
not decrement the shard count in the utilization when we de-schedule the
shards from before the split, the controller will now prefer to pick
_different_ nodes for shards compared with which ones held secondaries
before the split. We could use our knowledge of splitting to fix up the
utilizations more actively in this situation, but I'm leaning toward
leaving the code simpler, as in practical systems the impact of one
shard on the utilization of a node should be fairly low (single digit
%).
part of https://github.com/neondatabase/neon/issues/8623
We want to discover potential aux v1 customers that we might have missed
from the migrations.
## Summary of changes
Log warnings on basebackup, load timeline, and the first put_file.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
This removes workspace hack from all libs, not from any binaries. This
does not change the behaviour of the hack.
Running
```
cargo clean
cargo build --release --bin proxy
```
Before this change took 5m16s. After this change took 3m3s. This is
because this allows the build to be parallelisable much more.
Per #8674, disallow node configuration while drain/fill are ongoing.
Implement it by adding a only-http wrapper
`Service::external_node_configure` which checks for operation existing
before configuring.
Additionally:
- allow cancelling drain/fill after a pageserver has restarted and
transitioned to WarmingUp
Fixes: #8674
## Problem
When the utilization API was added, it was just a stub with disk space
information.
Disk space information isn't a very good metric for assigning tenants to
pageservers, because pageservers making full use of their disks would
always just have 85% utilization, irrespective of how much pressure they
had for disk space.
## Summary of changes
- Use the new layer visibiilty metric to calculate a "wanted size" per
tenant, and sum these to get a total local disk space wanted per
pageserver. This acts as the primary signal for utilization.
- Also use the shard count to calculate a utilization score, and take
the max of this and the disk-driven utilization. The shard count limit
is currently set as a constant 20,000, which matches contemporary
operational practices when loading pageservers.
The shard count limit means that for tiny/empty tenants, on a machine
with 3.84TB disk, each tiny tenant influences the utilization score as
if it had size 160MB.
## Problem
This follows a PR that insists all input keys are representable in 16
bytes:
- https://github.com/neondatabase/neon/pull/8648
& a PR that prevents postgres from sending us keys that use the high
bits of field2:
- https://github.com/neondatabase/neon/pull/8657
Motivation for this change:
1. Ingest is bottlenecked on CPU
2. InMemoryLayer can create huge (~1M value) BTreeMap<Key,_> for its
index.
3. Maps over i128 are much faster than maps over an arbitrary 18 byte
struct.
It may still be worthwhile to make the index two-tier to optimize for
the case where only the last 4 bytes (blkno) of the key vary frequently,
but simply using the i128 representation of keys has a big impact for
very little effort.
Related: #8452
## Summary of changes
- Introduce `CompactKey` type which contains an i128
- Use this instead of Key in InMemoryLayer's index, converting back and
forth as needed.
## Performance
All the small-value `bench_ingest` cases show improved throughput.
The one that exercises this index most directly shows a 35% throughput
increase:
```
ingest-small-values/ingest 128MB/100b seq, no delta
time: [374.29 ms 378.56 ms 383.38 ms]
thrpt: [333.88 MiB/s 338.13 MiB/s 341.98 MiB/s]
change:
time: [-26.993% -26.117% -25.111%] (p = 0.00 < 0.05)
thrpt: [+33.531% +35.349% +36.974%]
Performance has improved.
```
Part of #8130, [RFC: Direct IO For Pageserver](https://github.com/neondatabase/neon/blob/problame/direct-io-rfc/docs/rfcs/034-direct-io-for-pageserver.md)
## Description
Add pageserver config for evaluating/enabling direct I/O.
- Disabled: current default, uses buffered io as is.
- Evaluate: still uses buffered io, but could do alignment checking and
perf simulation (pad latency by direct io RW to a fake file).
- Enabled: uses direct io, behavior on alignment error is configurable.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Earlier I was thinking we'd need a (ancestor_lsn, timeline_id) ordered
list of reparented. Turns out we did not need it at all. Replace it with
an unordered hashset. Additionally refactor the reparented direct
children query out, it will later be used from more places.
Split off from #8430.
Cc: #6994
Currently, we do not have facilities to persistently block GC on a
tenant for whatever reason. We could do a tenant configuration update,
but that is risky for generation numbers and would also be transient.
Introduce a `gc_block` facility in the tenant, which manages per
timeline blocking reasons.
Additionally, add HTTP endpoints for enabling/disabling manual gc
blocking for a specific timeline. For debugging, individual tenant
status now includes a similar string representation logged when GC is
skipped.
Cc: #6994
Part of #8128, followup to #8480. closes#8421.
Enable scrubber to optionally post metadata scan health results to
storage controller.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Part of #8128, followed by #8502.
## Problem
Currently we lack mechanism to alert unhealthy `scan_metadata` status if
we start running this scrubber command as part of a cronjob. With the
storage controller client introduced to storage scrubber in #8196, it is
viable to set up alert by storing health status in the storage
controller database.
We intentionally do not store the full output to the database as the
json blobs potentially makes the table really huge. Instead, only a
health status and a timestamp recording the last time metadata health
status is posted on a tenant shard.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
## Problem
Re-attach blocks the pageserver http server from starting up. Hence, it
can't reply to heartbeats
until that's done. This makes the storage controller mark the node
off-line (not good). We worked
around this by setting the interval after which nodes are marked offline
to 5 minutes. This isn't a
long term solution.
## Summary of changes
* Introduce a new `NodeAvailability` state: `WarmingUp`. This state
models the following time interval:
* From receiving the re-attach request until the pageserver replies to
the first heartbeat post re-attach
* The heartbeat delta generator becomes aware of this state and uses a
separate longer interval
* Flag `max-warming-up-interval` now models the longer timeout and
`max-offline-interval` the shorter one to
match the names of the states
Closes https://github.com/neondatabase/neon/issues/7552
## Problem
LayerAccessStats contains a lot of detail that we don't use: short
histories of most recent accesses, specifics on what kind of task
accessed a layer, etc. This is all stored inside a Mutex, which is
locked every time something accesses a layer.
## Summary of changes
- Store timestamps at a very low resolution (to the nearest second),
sufficient for use on the timescales of eviction.
- Pack access time and last residence change time into a single u64
- Use the high bits of the u64 for other flags, including the new layer
visibility concept.
- Simplify the external-facing model for access stats to just include
what we now track.
Note that the `HistoryBufferWithDropCounter` is removed here because it
is no longer used. I do not dislike this type, we just happen not to use
it for anything else at present.
Co-authored-by: Christian Schwarz <christian@neon.tech>
This adds an archival_config endpoint to the pageserver. Currently it
has no effect, and always "works", but later the intent is that it will
make a timeline archived/unarchived.
- [x] add yml spec
- [x] add endpoint handler
Part of https://github.com/neondatabase/neon/issues/8088
## Problem
After a shard split, the pageserver leaves the ancestor shard's content
in place. It may be referenced by child shards, but eventually child
shards will de-reference most ancestor layers as they write their own
data and do GC. We would like to eventually clean up those ancestor
layers to reclaim space.
## Summary of changes
- Extend the physical GC command with `--mode=full`, which includes
cleaning up unreferenced ancestor shard layers
- Add test `test_scrubber_physical_gc_ancestors`
- Remove colored log output: in testing this is irritating ANSI code
spam in logs, and in interactive use doesn't add much.
- Refactor storage controller API client code out of storcon_client into
a `storage_controller/client` crate
- During physical GC of ancestors, call into the storage controller to
check that the latest shards seen in S3 reflect the latest state of the
tenant, and there is no shard split in progress.
Currently storage controller does not support forwarding timeline detach
ancestor requests to pageservers. Add support for forwarding `PUT
.../:tenant_id/timelines/:timeline_id/detach_ancestor`. Implement the
support mostly as is, because the timeline detach ancestor will be made
(mostly) idempotent in future PR.
Cc: #6994
`trace_read_requests` is a per `Tenant`-object option.
But the `handle_pagerequests` loop doesn't know which
`Tenant` object (i.e., which shard) the request is for.
The remaining use of the `Tenant` object is to check `tenant.cancel`.
That check is incorrect [if the pageserver hosts multiple
shards](https://github.com/neondatabase/neon/issues/7427#issuecomment-2220577518).
I'll fix that in a future PR where I completely eliminate the holding
of `Tenant/Timeline` objects across requests.
See [my code RFC](https://github.com/neondatabase/neon/pull/8286) for
the
high level idea.
Note that we can always bring the tracing functionality if we need it.
But since it's actually about logging the `page_service` wire bytes,
it should be a `page_service`-level config option, not per-Tenant.
And for enabling tracing on a single connection, we can implement
a `set pageserver_trace_connection;` option.
Removes the `ImageCompressionAlgorithm::DisabledNoDecompress` variant.
We now assume any blob with the specific bits set is actually a
compressed blob.
The `ImageCompressionAlgorithm::Disabled` variant still remains and is
the new default.
Reverts large parts of #8238 , as originally intended in that PR.
Part of #5431
## Problem
LSN Leases introduced in #8084 is a new API that is made shard-aware
from day 1. To support ephemeral endpoint in #7994 without linking
Postgres C API against `compute_ctl`, part of the sharding needs to
reside in `utils`.
## Summary of changes
- Create a new `shard` module in utils crate.
- Move more interface related part of tenant sharding API to utils and
re-export them in pageserver_api.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Improve parsing of the `ImageCompressionAlgorithm` enum to allow level
customization like `zstd(1)`, as strum only takes `Default::default()`,
i.e. `None` as the level.
Part of #5431
Part of #7497, closes#8071. (accidentally closed#8208, reopened here)
## Problem
After the changes in #8084, we need synthetic size to also account for
leased LSNs so that users do not get free retention by running a small
ephemeral endpoint for a long time.
## Summary of changes
This PR integrates LSN leases into the synthetic size calculation. We
model leases as read-only branches started at the leased LSN (except it
does not have a timeline id).
Other changes:
- Add new unit tests testing whether a lease behaves like a read-only
branch.
- Change `/size_debug` response to include lease point in the SVG
visualization.
- Fix `/lsn_lease` HTTP API to do proper parsing for POST.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
## Problem
The metrics we have today aren't convenient for planning around the
impact of timeline archival on costs.
Closes: https://github.com/neondatabase/neon/issues/8108
## Summary of changes
- Add metric `pageserver_archive_size`, which indicates the logical
bytes of data which we would expect to write into an archived branch.
- Add metric `pageserver_pitr_history_size`, which indicates the
distance between last_record_lsn and the PITR cutoff.
These metrics are somewhat temporary: when we implement #8088 and
associated consumption metric changes, these will reach a final form.
For now, an "archived" branch is just any branch outside of its parent's
PITR window: later, archival will become an explicit state (which will
_usually_ correspond to falling outside the parent's PITR window).
The overall volume of timeline metrics is something to watch, but we are
removing many more in https://github.com/neondatabase/neon/pull/8245
than this PR is adding.
Add support for reading and writing zstd-compressed blobs for use in
image layer generation, but maybe one day useful also for delta layers.
The reading of them is unconditional while the writing is controlled by
the `image_compression` config variable allowing for experiments.
For the on-disk format, we re-use some of the bitpatterns we currently
keep reserved for blobs larger than 256 MiB. This assumes that we have
never ever written any such large blobs to image layers.
After the preparation in #7852, we now are unable to read blobs with a
size larger than 256 MiB (or write them).
A non-goal of this PR is to come up with good heuristics of when to
compress a bitpattern. This is left for future work.
Parts of the PR were inspired by #7091.
cc #7879
Part of #5431
## Problem
At high percentiles we see more than 800 layers being visited by the
read path. We need the tenant/timeline to investigate.
## Summary of changes
Add a rate limited log line when the average number of layers visited
per key is in the last specified histogram bucket.
I plan to use this to identify tenants in us-east-2 staging that exhibit
this behaviour. Will revert before next week's release.
## Problem
For some time, we have created tenants with calls to location_conf. The
legacy "POST /v1/tenant" path was only used in some tests.
## Summary of changes
- Remove the API
- Relocate TenantCreateRequest to the controller API file (this used to
be used in both pageserver and controller APIs)
- Rewrite tenant_create test helper to use location_config API, as
control plane and storage controller do
- Update docker-compose test script to create tenants with
location_config API (this small commit is also present in
https://github.com/neondatabase/neon/pull/7947)
## Problem
In https://github.com/neondatabase/neon/pull/5299, the new config-v1
tenant config file was added to hold the LocationConf type. We left the
old config file in place for forward compat, and because running without
generations (therefore without LocationConf) as still useful before the
storage controller was ready for prime-time.
Closes: https://github.com/neondatabase/neon/issues/5388
## Summary of changes
- Remove code for reading and writing the legacy config file
- Remove Generation::Broken: it was unused.
- Treat missing config file on disk as an error loading a tenant, rather
than defaulting it. We can now remove LocationConf::default, and thereby
guarantee that we never construct a tenant with a None generation.
- Update some comments + add some assertions to clarify that
Generation::None is only used in layer metadata, not in the state of a
running tenant.
- Update docker compose test to create tenants with a generation
part of https://github.com/neondatabase/neon/issues/8002
## Summary of changes
This pull request adds the image layer iterator. It buffers a fixed
amount of key-value pairs in memory, and give developer an iterator
abstraction over the image layer. Once the buffer is exhausted, it will
issue 1 I/O to fetch the next batch.
Due to the Rust lifetime mysteries, the `get_stream_from` API has been
refactored to `into_stream` and consumes `self`.
Delta layer iterator implementation will be similar, therefore I'll add
it after this pull request gets merged.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
These APIs have been deprecated for some time, but were still used from
test code.
Closes: https://github.com/neondatabase/neon/issues/4282
## Summary of changes
- It is still convenient to do a "tenant_attach" from a test without
having to write out a location_conf body, so those test methods have
been retained with implementations that call through to their
location_conf equivalent.
## Problem
These APIs have be unused for some time. They were superseded by
/location_conf: the equivalent of ignoring a tenant is now to put it in
secondary mode.
## Summary of changes
- Remove APIs
- Remove tests & helpers that used them
- Remove error variants that are no longer needed.
## Problem
Pageserver restarts cause read availablity downtime for tenants. See
`Motivation` section in the
[RFC](https://github.com/neondatabase/neon/pull/7704).
## Summary of changes
* Introduce a new `NodeSchedulingPolicy`: `PauseForRestart`
* Implement the first take of drain and fill algorithms
* Add a node status endpoint which can be polled to figure out when an
operation is done
The implementation follows the RFC, so it might be useful to peek at it
as you're reviewing.
Since the PR is rather chunky, I've made sure all commits build (with
warnings), so you can
review by commit if you prefer that.
RFC: https://github.com/neondatabase/neon/pull/7704
Related https://github.com/neondatabase/neon/issues/7387
Part of #7497, extracts from #7996, closes#8063.
## Problem
With the LSN lease API introduced in
https://github.com/neondatabase/neon/issues/7808, we want to implement
the real lease logic so that GC will
keep all the layers needed to reconstruct all pages at all the leased
LSNs with valid leases at a given time.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
Store logical replication origin in KV storage
## Problem
See #6977
## Summary of changes
* Extract origin_lsn from commit WAl record
* Add ReplOrigin key to KV storage and store origin_lsn
* In basebackup replace snapshot origin_lsn with last committed
origin_lsn at basebackup LSN
## Checklist before requesting a review
- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
Co-authored-by: Alex Chi Z <chi@neon.tech>
The keyspace utils like `is_rel_size_key` or `is_rel_fsm_block_key` and
many others are free functions and have to be either imported separately
or specified with the full path starting in `pageserver_api:🔑:`.
This is less convenient than if these functions were just inherent
impls.
Follow-up of #7890Fixes#6438
field2 of metadata keys can be 0xFFFF because of the mapping. Allow
0xFFFF for `to_i128`. An alternative is to encode 0xFFFF as 0xFFFFFFFF
(which is allowed in the original `to_i128`). But checking the places
where field2 is referenced, the rest part of the system does not seem to
depend on this assertion.
Signed-off-by: Alex Chi Z <chi@neon.tech>