## Problem
- using Hetzner buckets for cache requires secrets, we either need
`secrets: inherit` to make it works
- we don't have self-hosted MacOs runners, so actually GH native cache
is more optimal solution there
## Summary of changes
- switch to GH native cache for macos builds
# Problem
The Pageserver read path exclusively uses direct IO if
`virtual_file_io_mode=direct`.
The write path is half-finished. Here is what the various writing
components use:
|what|buffering|flags on <br/>`v_f_io_mode`<br/>=`buffered`|flags on
<br/>`virtual_file_io_mode`<br/>=`direct`|
|-|-|-|-|
|`DeltaLayerWriter`| BlobWriter<BUFFERED=true> | () | () |
|`ImageLayerWriter`| BlobWriter<BUFFERED=false> | () | () |
|`download_layer_file`|BufferedWriter|()|()|
|`InMemoryLayer`|BufferedWriter|()|O_DIRECT|
The vehicle towards direct IO support is `BufferedWriter` which
- largely takes care of O_DIRECT alignment & size-multiple requirements
- double-buffering to mask latency
`DeltaLayerWriter`, `ImageLayerWriter` use `blob_io::BlobWriter` , which
has neither of these.
# Changes
## High-Level
At a high-level this PR makes the following primary changes:
- switch the two layer writer types to use `BufferedWriter` & make
sensitive to `virtual_file_io_mode` (via open_with_options_**v2**)
- make `download_layer_file` sensitive to `virtual_file_io_mode` (also
via open_with_options_**v2**)
- add `virtual_file_io_mode=direct-rw` as a feature gate
- we're hackish-ly piggybacking on OpenOptions's ask for write access
here
- this means with just `=direct` InMemoryLayer reads and writes no
longer uses O_DIRECT
- this is transitory and we'll remove the `direct-rw` variant once the
rollout is complete
(The `_v2` APIs for opening / creating VirtualFile are those that are
sensitive to `virtual_file_io_mode`)
The result is:
|what|uses <br/>`BufferedWriter`|flags on
<br/>`v_f_io_mode`<br/>=`buffered`|flags on
<br/>`v_f_io_mode`<br/>=`direct`|flags on
<br/>`v_f_io_mode`<br/>=`direct-rw`|
|-|-|-|-|-|
|`DeltaLayerWriter`| ~~Blob~~BufferedWriter | () | () | O_DIRECT |
|`ImageLayerWriter`| ~~Blob~~BufferedWriter | () | () | O_DIRECT |
|`download_layer_file`|BufferedWriter|()|()|O_DIRECT|
|`InMemoryLayer`|BufferedWriter|()|~~O_DIRECT~~()|O_DIRECT|
## Code-Level
The main change is:
- Switch `blob_io::BlobWriter` away from its own buffering method to use
`BufferedWriter`.
Additional prep for upholding `O_DIRECT` requirements:
- Layer writer `finish()` methods switched to use IoBufferMut for
guaranteed buffer address alignment. The size of the buffers is PAGE_SZ
and thereby implicitly assumed to fulfill O_DIRECT requirements.
For the hacky feature-gating via `=direct-rw`:
- Track `OpenOptions::write(true|false)` in a field; bunch of mechanical
churn.
- Consolidate the APIs in which we "open" or "create" VirtualFile for
better overview over which parts of the code use the `_v2` APIs.
Necessary refactorings & infra work:
- Add doc comments explaining how BufferedWriter ensures that writes are
compliant with O_DIRECT alignment & size constraints. This isn't new,
but should be spelled out.
- Add the concept of shutdown modes to `BufferedWriter::shutdown` to
make writer shutdown adhere to these constraints.
- The `PadThenTruncate` mode might not be necessary in practice because
I believe all layer files ever written are sized in multiples `PAGE_SZ`
and since `PAGE_SZ` is larger than the current alignment requirements
(512/4k depending on platform), it won't be necesary to pad.
- Some test (I believe `round_trip_test_compressed`?) required it though
- [ ] TODO: decide if we want to accept that complexity; if we do then
address TODO in the code to separate alignment requirement from buffer
capacity
- Add `set_len` (=`ftruncate`) VirtualFile operation to support the
above.
- Allow `BufferedWriter` to start at a non-zero offset (to make room for
the summary block).
Cleanups unlocked by this change:
- Remove non-positional APIs from VirtualFile (e.g. seek, write_full,
read_full)
Drive-by fixes:
- PR https://github.com/neondatabase/neon/pull/11585 aimed to run unit
tests for all `virtual_file_io_mode` combinations but didn't because of
a missing `_` in the env var.
# Performance
This section assesses this PR's impact on deployments with current
production setting (`=direct`) and anticipated impact of switching to
(`=direct-rw`).
For `DeltaLayerWriter`, `=direct` should remain unchanged to slightly
improved on throughput because the `BlobWriter`'s buffer had the same
size as the `BufferedWriter`'s buffer, but it didn't have the
double-buffering that `BufferedWriter` has.
The `=direct-rw` enables direct IO; throughput should not be suffering
because of double-buffering; benchmarks will show if this is true.
The `ImageLayerWriter` was previously not doing any buffering
(`BUFFERED=false`).
It went straight to issuing the IO operation to the underlying
VirtualFile and the buffering was done by the kernel.
The switch to `BufferedWriter` under `=direct` adds an additional memcpy
into the BufferedWriter's buffer.
We will win back that memcpy when enabling direct IO via `=direct-rw`.
A nice win from the switch to `BufferedWriter` is that ImageLayerWriter
performs >=16x fewer write operations to VirtualFile (the BlobWriter
performs one write per len field and one write per image value).
This should save low tens of microseconds of CPU overhead from doing all
these syscalls/io_uring operations, regardless of `=direct` or
`=direct-rw`.
Aside from problems with alignment, this write frequency without
double-buffering is prohibitive if we actually have to wait for the
disk, which is what will happen when we enable direct IO via
(`=direct-rw`).
Throughput should not be suffering because of BufferedWrite's
double-buffering; benchmarks will show if this is true.
`InMemoryLayer` at `=direct` will flip back to using buffered IO but
remain on BufferedWriter.
The buffered IO adds back one memcpy of CPU overhead.
Throughput should not suffer and will might improve on
not-memory-pressured Pageservers but let's remember that we're doing the
whole direct IO thing to eliminate global memory pressure as a source of
perf variability.
## bench_ingest
I reran `bench_ingest` on `im4gn.2xlarge` and `Hetzner AX102`.
Use `git diff` with `--word-diff` or similar to see the change.
General guidance on interpretation:
- immediate production impact of this PR without production config
change can be gauged by comparing the same `io_mode=Direct`
- end state of production switched over to `io_mode=DirectRw` can be
gauged by comparing old results' `io_mode=Direct` to new results'
`io_mode=DirectRw`
Given above guidance, on `im4gn.2xlarge`
- immediate impact is a significant improvement in all cases
- end state after switching has same significant improvements in all
cases
- ... except `ingest/io_mode=DirectRw volume_mib=128 key_size_bytes=8192
key_layout=Sequential write_delta=Yes` which only achieves `238 MiB/s`
instead of `253.43 MiB/s`
- this is a 6% degradation
- this workload is typical for image layer creation
# Refs
- epic https://github.com/neondatabase/neon/issues/9868
- stacked atop
- preliminary refactor https://github.com/neondatabase/neon/pull/11549
- bench_ingest overhaul https://github.com/neondatabase/neon/pull/11667
- derived from https://github.com/neondatabase/neon/pull/10063
Co-authored-by: Yuchen Liang <yuchen@neon.tech>
## Problem
https://github.com/neondatabase/neon/actions/runs/14538136318/job/40790985693?pr=11645
failed, even though the relevant parts of the CI had passed and
auto-merge determined the PR is ready to merge. After that, commenting
failed.
## Summary of changes
- set GH_TOKEN for commenting after fast-forward failure
- allow merging with mergeable_state unstable
## Problem
We need to test the stability of Neon.
## Summary of changes
The test runs random operations on a Neon project. It performs via the
Public API calls the following operations: `create a branch`, `delete a
branch`, `add a read-only endpoint`, `delete a read-only endpoint`,
`restore a branch to a random position in the past`. All the branches
and endpoints are loaded with `pgbench`.
---------
Co-authored-by: Peter Bendel <peterbendel@neon.tech>
Co-authored-by: Alexander Bayandin <alexander@neon.tech>
## Problem
`pg-clients` can't start:
```
The workflow is not valid. .github/workflows/pg-clients.yml (Line: 44, Col: 3): Error calling workflow 'neondatabase/neon/.github/workflows/build-build-tools-image.yml@aa19f10e7e958fbe0e0641f2e8c5952ce3be44b3'. The nested job 'check-image' is requesting 'packages: read', but is only allowed 'packages: none'. .github/workflows/pg-clients.yml (Line: 44, Col: 3): Error calling workflow 'neondatabase/neon/.github/workflows/build-build-tools-image.yml@aa19f10e7e958fbe0e0641f2e8c5952ce3be44b3'. The nested job 'build-image' is requesting 'packages: write', but is only allowed 'packages: none'.
```
## Summary of changes
- Grant required `packages: write` permissions to the workflow
This is mostly a documentation update, but a few updates with regard to
neon_local, pageserver, and tests.
17 is our default for users in production, so dropping references to 16
makes sense.
Signed-off-by: Tristan Partin <tristan@neon.tech>
Signed-off-by: Tristan Partin <tristan@neon.tech>
## Problem
We can't have more than one open release PR created on the same day (due
to non-unique enough branch names).
## Summary of changes
- Add time (hours and minutes) to RC PR branch names
- Also make sure we use UTC for releases
## Problem
There is too much delay between merging a PR into `main` and deploying
the changes to staging
## Summary of changes
- Trigger `deploy` job without waiting for `build-and-test-locally` job
## Problem
Benchmarks results are inconsistent on existing small-metal runners
## Summary of changes
Introduce new `unit-perf` runners, and lets run benchmark on them.
The new hardware has slower, but consistent, CPU frequency - if run with
default governor schedutil.
Thus we needed to adjust some testcases' timeouts and add some retry
steps where hard-coded timeouts couldn't be increased without changing
the system under test.
-
[wait_for_last_record_lsn](6592d69a67/test_runner/fixtures/pageserver/utils.py (L193))
1000s -> 2000s
-
[test_branch_creation_many](https://github.com/neondatabase/neon/pull/11409/files#diff-2ebfe76f89004d563c7e53e3ca82462e1d85e92e6d5588e8e8f598bbe119e927)
1000s
-
[test_ingest_insert_bulk](https://github.com/neondatabase/neon/pull/11409/files#diff-e90e685be4a87053bc264a68740969e6a8872c8897b8b748d0e8c5f683a68d9f)
- with back throttling disabled compute becomes unresponsive for more
than 60 seconds (PG hard-coded client authentication connection timeout)
-
[test_sharded_ingest](https://github.com/neondatabase/neon/pull/11409/files#diff-e8d870165bd44acb9a6d8350f8640b301c1385a4108430b8d6d659b697e4a3f1)
600s -> 1200s
Right now there are only 2 runners of that class, and if we decide to go
with them, we have to check how much that type of runners we need, so
jobs not stuck with waiting for that type of runners available.
However we now decided to run those runners with governor performance
instead of schedutil.
This achieves almost same performance as previous runners but still
achieves consistent results for same commit
Related issue to activate performance governor on these runners
https://github.com/neondatabase/runner/pull/138
## Verification that it helps
### analyze runtimes on new runner for same commit
Table of runtimes for the same commit on different runners in
[run](https://github.com/neondatabase/neon/actions/runs/14417589789)
| Run | Benchmarks (1) | Benchmarks (2) |Benchmarks (3) |Benchmarks (4)
| Benchmarks (5) |
|--------|--------|---------|---------|---------|---------|
| 1 | 1950.37s | 6374.55s | 3646.15s | 4149.48s | 2330.22s |
| 2 | - | 6369.27s | 3666.65s | 4162.42s | 2329.23s |
| Delta % | - | 0,07 % | 0,5 % | 0,3 % | 0,04 % |
| with governor performance | 1519.57s | 4131.62s | - | - | - |
| second run gov. perf. | 1513.62s | 4134.67s | - | - | - |
| Delta % | 0,3 % | 0,07 % | - | - | - |
| speedup gov. performance | 22 % | 35 % | - | - | - |
| current desktop class hetzner runners (main) | 1487.10s | 3699.67s | -
| - | - |
| slower than desktop class | 2 % | 12 % | - | - | - |
In summary, the runtimes for the same commit on this hardware varies
less than 1 %.
---------
Co-authored-by: BodoBolero <peterbendel@neon.tech>
## Problem
We've started sending slack notifications for failed container image
pushes that are being retried. There are more messages coming in than
expected, so clicking through the link to see what image failed is
happening more often than we hoped.
## Summary of changes
- Make slack notifications clearer, including whether the job succeeded
and what retries have happened.
- Log failures/retries in step more clearly, so that you can easily see
when something fails.
## Problem
Changes in compute can cause errors in tests if another version of
`neon-test-extensions` image is used.
## Summary of changes
Use the same version of `neon-test-extensions` image as `compute` one
for docker-compose based extension tests.
## Problem
We've seen quite a few CI failures related to pushes to docker hub
failing with weird error messages that indicate maybe docker hub is just
not reliable.
## Summary of changes
Retry container image pushing up to 10 times, and send a slack message
if we had to retry, regardless of the job succeeding or not.
## Problem
Hotfix releases mean that sometimes changes in release PRs haven't been
tested and linted yet. Disabling tests and lints is therefore not
necessarily safe. In the future we will check whether tests have run on
the same git tree already to speed things up, but for now we need to
turn tests back on fully. This partially reverts:
https://github.com/neondatabase/neon/pull/11272
## Summary of changes
Run checks on `.*-rc-pr` runs.
## Problem
Sometimes the forced extension upgrade test fails (on schedule) due to a
timeout.
## Summary of changes
The timeout is increased to 60 mins.
