### Describe Your Changes
By default `zstd.Reader` creates multiple goroutines to process a single
connection:
- It doesn't match cgo behavior, which works synchronously, and creates
a lot more concurrent goroutines (0.5k -> 5k on my workload)
- It results in non-zero `vm_tcpdialer_errors_total{type="read"}` errors
on vmselect because an underlying connection is closed while a goroutine
is still reading from it. The goroutine created by
`zstd.NewReader`/`zstd.Reset`
abb348e4db/lib/handshake/buffered_conn.go (L113-L120)
- vmselect (and vmagent) doesn't benefit from async mode since it has
multiple readers in-use at the same time, which usually exceeds the
number of cpu cores
Partly related to #9218
### Checklist
The following checks are **mandatory**:
- [x] My change adheres to [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/victoriametrics/contributing/#pull-request-checklist).
- [x] My change adheres to [VictoriaMetrics development
goals](https://docs.victoriametrics.com/victoriametrics/goals/).
It is faster to read the whole data and then decompress it in one go for zstd and snappy encodings.
This reduces the number of potential read() syscalls and decompress CGO calls needed
for reading and decompressing the data.
- Properly decode protobuf-encoded Loki request if it has no Content-Encoding header.
Protobuf Loki message is snappy-encoded by default, so snappy decoding must be used
when Content-Encoding header is missing.
- Return back the previous signatures of parseJSONRequest and parseProtobufRequest functions.
This eliminates the churn in tests for these functions. This also fixes broken
benchmarks BenchmarkParseJSONRequest and BenchmarkParseProtobufRequest, which consume
the whole request body on the first iteration and do nothing on subsequent iterations.
- Put the CHANGELOG entries into correct places, since they were incorrectly put into already released
versions of VictoriaMetrics and VictoriaLogs.
- Add support for reading zstd-compressed data ingestion requests into the remaining protocols
at VictoriaLogs and VictoriaMetrics.
- Remove the `encoding` arg from PutUncompressedReader() - it has enough information about
the passed reader arg in order to properly deal with it.
- Add ReadUncompressedData to lib/protoparser/common for reading uncompressed data from the reader until EOF.
This allows removing repeated code across request-based protocol parsers without streaming mode.
- Consistently limit data ingestion request sizes, which can be read by ReadUncompressedData function.
Previously this wasn't the case for all the supported protocols.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/8416
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8380
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8300
This eliminates the need in .(*T) casting for results obtained from Load()
Leave atomic.Value for map, since atomic.Pointer[map[...]...] makes double pointer to map,
because map is already a pointer type.
