Earlier work (#7547) has made the scrubber internally generic, but one
could only configure it to use S3 storage.
This is the final piece to make (most of, snapshotting still requires
S3) the scrubber be able to be configured via GenericRemoteStorage.
I.e. you can now set an env var like:
```
REMOTE_STORAGE_CONFIG='remote_storage = { bucket_name = "neon-dev-safekeeper-us-east-2d", bucket_region = "us-east-2" }
```
and the scrubber will read it instead.
## Problem
`no_sync` initially just skipped syncfs on startup (#9677). I'm also
interested in flaky tests that time out during pageserver shutdown while
flushing l0s, so to eliminate disk throughput as a source of issues
there,
## Summary of changes
- Drive-by change for test timeouts: add a couple more ::info logs
during pageserver startup so it's obvious which part got stuck.
- Add a SyncMode enum to configure VirtualFile and respect it in
sync_all and sync_data functions
- During pageserver startup, set SyncMode according to `no_sync`
This patch contains various improvements for the pagectl tool.
## Summary of changes
* Rewrite layer name parsing: LayerName now supports all variants we use
now.
* Drop pagectl's own layer parsing function, use LayerName in the
pageserver crate.
* Support image layer dumping in the layer dump command using
ImageLayer::dump, drop the original implementation.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
We wish to have high level WAL decoding logic in `wal_decoder::decoder`
module.
## Summary of Changes
For this we need the `Value` and `NeonWalRecord` types accessible there, so:
1. Move `Value` and `NeonWalRecord` to `pageserver::value` and
`pageserver::record` respectively.
2. Get rid of `pageserver::repository` (follow up from (1))
3. Move PG specific WAL record types to `postgres_ffi::walrecord`. In
theory they could live in `wal_decoder`, but it would create a circular
dependency between `wal_decoder` and `postgres_ffi`. Long term it makes
sense for those types to be PG version specific, so that will work out nicely.
4. Move higher level WAL record types (to be ingested by pageserver)
into `wal_decoder::models`
Related: https://github.com/neondatabase/neon/issues/9335
Epic: https://github.com/neondatabase/neon/issues/9329
Part of #8130
## Problem
Pageserver previously goes through the kernel page cache for all the
IOs. The kernel page cache makes light-loaded pageserver have deceptive
fast performance. Using direct IO would offer predictable latencies of
our virtual file IO operations.
In particular for reads, the data pages also have an extremely low
temporal locality because the most frequently accessed pages are cached
on the compute side.
## Summary of changes
This PR enables pageserver to use direct IO for delta layer and image
layer reads. We can ship them separately because these layers are
write-once, read-many, so we will not be mixing buffered IO with direct
IO.
- implement `IoBufferMut`, an buffer type with aligned allocation
(currently set to 512).
- use `IoBufferMut` at all places we are doing reads on image + delta
layers.
- leverage Rust type system and use `IoBufAlignedMut` marker trait to
guarantee that the input buffers for the IO operations are aligned.
- page cache allocation is also made aligned.
_* in-memory layer reads and the write path will be shipped separately._
## Testing
Integration test suite run with O_DIRECT enabled:
https://github.com/neondatabase/neon/pull/9350
## Performance
We evaluated performance based on the `get-page-at-latest-lsn`
benchmark. The results demonstrate a decrease in the number of IOps, no
sigificant change in the latency mean, and an slight improvement on the
p99.9 and p99.99 latencies.
[Benchmark](https://www.notion.so/neondatabase/Benchmark-O_DIRECT-for-image-and-delta-layers-2024-10-01-112f189e00478092a195ea5a0137e706?pvs=4)
## Rollout
We will add `virtual_file_io_mode=direct` region by region to enable
direct IO on image + delta layers.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
## Problem
We need a way to incrementally switch to direct IO. During the rollout
we might want to switch to O_DIRECT on image and delta layer read path
first before others.
## Summary of changes
- Revisited and simplified direct io config in `PageserverConf`.
- We could add a fallback mode for open, but for read there isn't a
reasonable alternative (without creating another buffered virtual file).
- Added a wrapper around `VirtualFile`, current implementation become
`VirtualFileInner`
- Use `open_v2`, `create_v2`, `open_with_options_v2` when we want to use
the IO mode specified in PS config.
- Once we onboard all IO through VirtualFile using this new API, we will
delete the old code path.
- Make io mode live configurable for benchmarking.
- Only guaranteed for files opened after the config change, so do it
before the experiment.
As an example, we are using `open_v2` with
`virtual_file::IoMode::Direct` in
https://github.com/neondatabase/neon/pull/9169
We also remove `io_buffer_alignment` config in
a04cfd754b and use it as a compile time
constant. This way we don't have to carry the alignment around or make
frequent call to retrieve this information from the static variable.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
This adds preliminary PG17 support to Neon, based on RC1 / 2024-09-04
07b828e9d4
NOTICE: The data produced by the included version of the PostgreSQL fork
may not be compatible with the future full release of PostgreSQL 17 due to
expected or unexpected future changes in magic numbers and internals.
DO NOT EXPECT DATA IN V17-TENANTS TO BE COMPATIBLE WITH THE 17.0
RELEASE!
Co-authored-by: Anastasia Lubennikova <anastasia@neon.tech>
Co-authored-by: Alexander Bayandin <alexander@neon.tech>
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
Co-authored-by: Heikki Linnakangas <heikki@neon.tech>
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
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>
Part of #8130, closes#8719.
## Problem
Currently, vectored blob io only coalesce blocks if they are immediately
adjacent to each other. When we switch to Direct IO, we need a way to
coalesce blobs that are within the dio-aligned boundary but has gap
between them.
## Summary of changes
- Introduces a `VectoredReadCoalesceMode` for `VectoredReadPlanner` and
`StreamingVectoredReadPlanner` which has two modes:
- `AdjacentOnly` (current implementation)
- `Chunked(<alignment requirement>)`
- New `ChunkedVectorBuilder` that considers batching `dio-align`-sized
read, the start and end of the vectored read will respect
`stx_dio_offset_align` / `stx_dio_mem_align` (`vectored_read.start` and
`vectored_read.blobs_at.first().start_offset` will be two different
value).
- Since we break the assumption that blobs within single `VectoredRead`
are next to each other (implicit end offset), we start to store blob end
offsets in the `VectoredRead`.
- Adapted existing tests to run in both `VectoredReadCoalesceMode`.
- The io alignment can also be live configured at runtime.
Signed-off-by: Yuchen Liang <yuchen@neon.tech>
PR #8299 has switched the storage scrubber to use
`DefaultCredentialsChain`. Now we do this for `remote_storage`, as it
allows us to use `remote_storage` from inside kubernetes. Most of the
diff is due to `GenericRemoteStorage::from_config` becoming `async fn`.
Before this PR, `RemoteStorageConfig::from_toml` would support
deserializing an
empty `{}` TOML inline table to a `None`, otherwise try `Some()`.
We can instead let
* in proxy: let clap derive handle the Option
* in PS & SK: assume that if the field is specified, it must be a valid
RemtoeStorageConfig
(This PR started with a much simpler goal of factoring out the
`deserialize_item` function because I need that in another PR).
We now have a `vX` number in the file name, i.e.,
`000000067F0000000400000B150100000000-000000067F0000000400000D350100000000__00000000014B7AC8-v1-00000001`
The related pull request for new-style path was merged a month ago
https://github.com/neondatabase/neon/pull/7660
## Summary of changes
Fixed the draw timeline dir command to handle it.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
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
RemoteTimelineClient maintains a copy of "next IndexPart" as a number of
fields which are like an IndexPart but this is not immediately obvious.
Instead of multiple fields, maintain a `dirty` ("next IndexPart") and
`clean` ("uploaded IndexPart") fields.
Additional cleanup:
- rename `IndexPart::disk_consistent_lsn` accessor
`duplicated_disk_consistent_lsn`
- no one except scrubber should be looking at it, even scrubber is a
stretch
- remove usage elsewhere (pagectl used by tests, metadata scan endpoint)
- serialize index part *before* the index upload operation
- avoid upload operation being retried because of serialization error
- serialization error is fatal anyway for timeline -- it can only make
transient local progress after that, at least the error is bubbled up
now
- gather exploded IndexPart fields into single actual
`UploadQueueInitialized::dirty` of which the uploaded snapshot is
serialized
- implement the long wished monotonicity check with the `clean`
IndexPart with an assertion which is not expected to fire
Continued work from #7860 towards next step of #6994.
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
Once upon a time, we used to have duplicated types for runtime IndexPart
and whatever we stored. Because of the serde fixes in #5335 we have no
need for duplicated IndexPart type anymore, but the `IndexLayerMetadata`
stayed.
- remove the type
- remove LayerFileMetadata::file_size() in favor of direct field access
Split off from #7833. Cc: #3072.
Part of https://github.com/neondatabase/neon/issues/7462
## Summary of changes
Tenant config is not persisted unless it's attached on the storage
controller. In this pull request, we persist the aux file policy flag in
the `index_part.json`.
Admins can set `switch_aux_file_policy` in the storage controller or
using the page server API. Upon the first aux file gets written, the
write path will compare the aux file policy target with the current
policy. If it is switch-able, we will do the switch. Otherwise, the
original policy will be used. The test cases show what the admins can do
/ cannot do.
The `last_aux_file_policy` is stored in `IndexPart`. Updates to the
persisted policy are done via
`schedule_index_upload_for_aux_file_policy_update`. On the write path,
the writer will update the field.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
## Problem
This is historical baggage from when the pageserver could be run with
local disk only: we had a bunch of places where we had to treat remote
storage as optional.
Closes: https://github.com/neondatabase/neon/issues/6890
## Changes
- Remove Option<> around remote storage (in
https://github.com/neondatabase/neon/pull/7722 we made remote storage
clearly mandatory)
- Remove code for deleting old metadata files: they're all gone now.
- Remove other references to metadata files when loading directories, as
none exist.
I checked last 14 days of logs for "found legacy metadata", there are no
instances.
## Problem
When layer paths include generations, the lsn parsing does not work and
`pagectl` errors out.
## Summary of changes
If the last "word" of the layer path contains 8 characters, discard it
for the purpose of lsn parsing.
in addition to layer names, expand the input vocabulary to recognize
lines in the form of:
${kind}:${lsn}
where:
- kind in `gc_cutoff` or `branch`
- lsn is accepted in Lsn display format (x/y) or hex (as used in layer
names)
gc_cutoff and branch have different colors.
- 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.
Adds another tool to the DR toolbox: ability in pagectl to
recover arbitrary prefixes in remote storage. Requires remote storage config,
the prefix, and the travel-to timestamp parameter
to be specified as cli args.
The done-if-after parameter is also supported.
Example invocation (after `aws login --profile dev`):
```
RUST_LOG=remote_storage=debug AWS_PROFILE=dev cargo run -p pagectl time-travel-remote-prefix 'remote_storage = { bucket_name = "neon-test-bucket-name", bucket_region = "us-east-2" }' wal/3aa8fcc61f6d357410b7de754b1d9001/641e5342083b2235ee3deb8066819683/ 2024-04-05T17:00:00Z
```
This has been written to resolve a customer recovery case:
https://neondb.slack.com/archives/C033RQ5SPDH/p1712256888468009
There is validation of the prefix to prevent accidentially specifying
too generic prefixes, which can cause corruption and data
loss if used wrongly. Still, the validation is not perfect and it is
important that the command is used with caution.
If possible, `time_travel_remote_storage` should
be used instead which has additional checks in place.
## Problem
The vectored read path proposed in
https://github.com/neondatabase/neon/pull/6576 seems
to be functionally correct, but in my testing (see below) it is about 10-20% slower than the naive
sequential vectored implementation.
## Summary of changes
There's three parts to this PR:
1. Supporting vectored blob reads. This is actually trickier than it
sounds because on disk blobs are prefixed with a variable length size header.
Since the blobs are not necessarily fixed size, we need to juggle the offsets
such that the callers can retrieve the blobs from the resulting buffer.
2. Merge disk read requests issued by the vectored read path up to a
maximum size. Again, the merging is complicated by the fact that blobs
are not fixed size. We keep track of the begin and end offset of each blob
and pass them into the vectored blob reader. In turn, the reader will return
a buffer and the offsets at which the blobs begin and end.
3. A benchmark for basebackup requests against tenant with large SLRU
block counts is added. This required a small change to pagebench and a new config
variable for the pageserver which toggles the vectored get validation.
We can probably optimise things further by adding a little bit of
concurrency for our IO. In principle, it's as simple as spawning a task which deals with issuing
IO and doing the serialisation and handling on the parent task which receives input via a
channel.
This PR adds an API to live-reconfigure the VirtualFile io engine.
It also adds a flag to `pagebench get-page-latest-lsn`, which is where I
found this functionality to be useful: it helps compare the io engines
in a benchmark without re-compiling a release build, which took ~50s on
the i3en.3xlarge where I was doing the benchmark.
Switching the IO engine is completely safe at runtime.
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.
Fixes#4689 by replacing all of `std::Path` , `std::PathBuf` with
`camino::Utf8Path`, `camino::Utf8PathBuf` in
- pageserver
- safekeeper
- control_plane
- libs/remote_storage
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
This PR adds a `task_kind` label to page cache access metrics.
These are to validate our hypothesis that the high hit page cache rate
we observe in prod is due to internal tasks, not getpage requests from
compute.
We believe the latter should near-always be a pageserver-page-cache
_miss_ because compute has it's own page cache, and hence there is no
locality of reference for its accesses to pageserver page cache.
Before this PR, we didn't have `RequestContext` propagation to any code
below the on-demand downloader.
The vast majority of changes in this PR is concerned with adding that
propagation.
## Problem
Once we use async file system APIs for `VirtualFile`, these functions
will also need to be async fn.
## Summary of changes
Makes the functions `open, open_with_options, create,sync_all,with_file`
of `VirtualFile` async fn, including all functions that call it. Like in
the prior PRs, the actual I/O operations are not using async APIs yet,
as per request in the #4743 epic.
We switch towards not using `VirtualFile` in the par_fsync module,
hopefully this is only temporary until we can actually do fully async
I/O in `VirtualFile`. This might cause us to exhaust fd limits in the
tests, but it should only be an issue for the local developer as we have
high ulimits in prod.
This PR is a follow-up of #5189, #5190, #5195, and #5203. Part of #4743.
## Problem
- Scrubber's `tidy` command requires presence of a control plane
- Scrubber has no tests at all
## Summary of changes
- Add re-usable async streams for reading metadata from a bucket
- Add a `scan-metadata` command that reads from those streams and calls
existing `checks.rs` code to validate metadata, then returns a summary
struct for the bucket. Command returns nonzero status if errors are
found.
- Add an `enable_scrub_on_exit()` function to NeonEnvBuilder so that
tests using remote storage can request to have the scrubber run after
they finish
- Enable remote storarge and scrub_on_exit in test_pageserver_restart
and test_pageserver_chaos
This is a "toe in the water" of the overall space of validating the
scrubber. Later, we should:
- Enable scrubbing at end of tests using remote storage by default
- Make the success condition stricter than "no errors": tests should
declare what tenants+timelines they expect to see in the bucket (or
sniff these from the functions tests use to create them) and we should
require that the scrubber reports on these particular tenants/timelines.
The `tidy` command is untouched in this PR, but it should be refactored
later to use similar async streaming interface instead of the current
batch-reading approach (the streams are faster with large buckets), and
to also be covered by some tests.
---------
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
Co-authored-by: Alexander Bayandin <alexander@neon.tech>
Co-authored-by: Christian Schwarz <christian@neon.tech>
Co-authored-by: Conrad Ludgate <conrad@neon.tech>
## Problem
`read_blk` does I/O and thus we would like to make it async. We can't
make the function async as long as the `PageReadGuard` returned by
`read_blk` isn't `Send`. The page cache is called by `read_blk`, and
thus it can't be async without `read_blk` being async. Thus, we have a
circular dependency.
## Summary of changes
Due to the circular dependency, we convert both the page cache and
`read_blk` to async at the same time:
We make the page cache use `tokio::sync` synchronization primitives as
those are `Send`. This makes all the places that acquire a lock require
async though, which we then also do. This includes also asyncification
of the `read_blk` function.
Builds upon #4994, #5015, #5056, and #5129.
Part of #4743.
## Problem
We want to make `read_blk` an async function, but outside of
`async_trait`, which allocates, and nightly features, we can't use async
fn's in traits.
## Summary of changes
* Remove all uses of `BlockReader::read_blk` in favour of using block
cursors, at least where the type of the `BlockReader` is behind a
generic
* Introduce a `BlockReaderRef` enum that lists all implementors of
`BlockReader::read_blk`.
* Remove `BlockReader::read_blk` and move its implementations into
inherent functions on the types instead.
We don't turn `read_blk` into an async fn yet, for that we also need to
modify the page cache. So this is a preparatory PR, albeit an important
one.
Part of #4743.
## Problem
The `BlockCursor::read_blob` and `BlockCursor::read_blob_into_buf`
functions are calling `read_blk` internally, so if we want to make that
function async fn, they need to be async themselves.
## Summary of changes
* We first turn `ValueRef::load` into an async fn.
* Then, we switch the `RwLock` implementation in `InMemoryLayer` to use
the one from `tokio`.
* Last, we convert the `read_blob` and `read_blob_into_buf` functions
into async fn.
In three instances we use `Handle::block_on`:
* one use is in compaction code, which currently isn't async. We put the
entire loop into an `async` block to prevent the potentially hot loop
from doing cross-thread operations.
* one use is in dumping code for `DeltaLayer`. The "proper" way to
address this would be to enable the visit function to take async
closures, but then we'd need to be generic over async fs non async,
which [isn't supported by rust right
now](https://blog.rust-lang.org/inside-rust/2022/07/27/keyword-generics.html).
The other alternative would be to do a first pass where we cache the
data into memory, and only then to dump it.
* the third use is in writing code, inside a loop that copies from one
file to another. It is is synchronous and we'd like to keep it that way
(for now?).
Part of #4743
## Problem
Running `pagectl draw-timeline` on a pageserver directory wasn't working
out of the box because it trips up on the `metadata` file.
## Summary of changes
Just ignore the `metadata` file in the list of input files passed to
`draw-timeline`.
## Problem
`DiskBtreeReader::get` and `DiskBtreeReader::visit` both call `read_blk`
internally, which we would like to make async in the future. This PR
focuses on making the interface of these two functions `async`. There is
further work to be done in forms of making `visit` to not be recursive
any more, similar to #4838. For that, see
https://github.com/neondatabase/neon/pull/4884.
Builds on top of https://github.com/neondatabase/neon/pull/4839, part of
https://github.com/neondatabase/neon/issues/4743
## Summary of changes
Make `DiskBtreeReader::get` and `DiskBtreeReader::visit` async functions
and `await` in the places that call these functions.
## Problem
The k-merge in pageserver compaction currently relies on iterators over
the keys and also over the values. This approach does not support async
code because we are using iterators and those don't support async in
general. Also, the k-merge implementation we use doesn't support async
either. Instead, as we already load all the keys into memory, the plan
is to just do the sorting in-memory for now, switch to async, and then
once we want to support workloads that don't have all keys stored in
memory, we can look into switching to a k-merge implementation that
supports async instead.
## Summary of changes
The core of this PR is the move from functions on the `PersistentLayer`
trait to return custom iterator types to inherent functions on `DeltaLayer`
that return buffers with all keys or value references.
Value references are a type we created in this PR, containing a
`BlobRef` as well as an `Arc` pointer to the `DeltaLayerInner`, so that
we can lazily load the values during compaction. This preserves the
property of the current code.
This PR does not switch us to doing the k-merge via sort on slices, but
with this PR, doing such a switch is relatively easy and only requires
changes of the compaction code itself.
Part of https://github.com/neondatabase/neon/issues/4743
In #4743, we'd like to convert the read path to use `async` rust. In
preparation of that, this PR switches some functions that are calling
lower level functions like `BlockReader::read_blk`,
`BlockCursor::read_blob`, etc into `async`. The PR does not switch all
functions however, and only focuses on the ones which are easy to
switch.
This leaves around some async functions that are (currently)
unnecessarily `async`, but on the other hand it makes future changes
smaller in diff.
Part of #4743 (but does not completely address it).
## Problem
`cargo +nightly doc` is giving a lot of warnings: broken links, naked
URLs, etc.
## Summary of changes
* update the `proc-macro2` dependency so that it can compile on latest
Rust nightly, see https://github.com/dtolnay/proc-macro2/pull/391 and
https://github.com/dtolnay/proc-macro2/issues/398
* allow the `private_intra_doc_links` lint, as linking to something
that's private is always more useful than just mentioning it without a
link: if the link breaks in the future, at least there is a warning due
to that. Also, one might enable
[`--document-private-items`](https://doc.rust-lang.org/cargo/commands/cargo-doc.html#documentation-options)
in the future and make these links work in general.
* fix all the remaining warnings given by `cargo +nightly doc`
* make it possible to run `cargo doc` on stable Rust by updating
`opentelemetry` and associated crates to version 0.19, pulling in a fix
that previously broke `cargo doc` on stable:
https://github.com/open-telemetry/opentelemetry-rust/pull/904
* Add `cargo doc` to CI to ensure that it won't get broken in the
future.
Fixes#2557
## Future work
* Potentially, it might make sense, for development purposes, to publish
the generated rustdocs somewhere, like for example [how the rust
compiler does
it](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_driver/index.html).
I will file an issue for discussion.
This PR refactors the original page_binutils with a single tool pagectl,
use clap derive for better command line parsing, and adds the dump kv
tool to extract information from delta file. This helps me better
understand what's inside the page server. We can add support for other
types of file and more functionalities in the future.
---------
Signed-off-by: Alex Chi <iskyzh@gmail.com>
