Awesome
<!--- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -->Apache Arrow for Go
Apache Arrow is a cross-language development platform for in-memory data. It specifies a standardized language-independent columnar memory format for flat and hierarchical data, organized for efficient analytic operations on modern hardware. It also provides computational libraries and zero-copy streaming messaging and inter-process communication.
A note about FlightSQL drivers
Go FlightSQL drivers live in the
ADBC repository.
In particular, to use the Golang database/sql
interface:
import (
"database/sql"
_ "github.com/apache/arrow-adbc/go/adbc/sqldriver/flightsql"
)
func main() {
dsn := "uri=grpc://localhost:12345;username=mickeymouse;password=p@55w0RD"
db, err := sql.Open("flightsql", dsn)
...
}
DSN option keys are expressed as k=v
, delimited with ;
.
Some options keys are defined in ADBC, others are defined in the FlightSQL ADBC driver.
- Arrow ADBC developer doc
- ADBC source code
- FlightSQL driver option keys source code
Reference Counting
The library makes use of reference counting so that it can track when memory
buffers are no longer used. This allows Arrow to update resource accounting,
pool memory such and track overall memory usage as objects are created and
released. Types expose two methods to deal with this pattern. The Retain
method will increase the reference count by 1 and Release
method will reduce
the count by 1. Once the reference count of an object is zero, any associated
object will be freed. Retain
and Release
are safe to call from multiple
goroutines.
When to call Retain
/ Release
?
-
If you are passed an object and wish to take ownership of it, you must call
Retain
. You must later pair this with a call toRelease
when you no longer need the object. "Taking ownership" typically means you wish to access the object outside the scope of the current function call. -
You own any object you create via functions whose name begins with
New
orCopy
or when receiving an object over a channel. Therefore you must callRelease
once you no longer need the object. -
If you send an object over a channel, you must call
Retain
before sending it as the receiver is assumed to own the object and will later callRelease
when it no longer needs the object.
Performance
The arrow package makes extensive use of c2goasm to leverage LLVM's
advanced optimizer and generate PLAN9 assembly functions from C/C++ code. The
arrow package can be compiled without these optimizations using the noasm
build tag. Alternatively, by configuring an environment variable, it is
possible to dynamically configure which architecture optimizations are used at
runtime. We use the (cpu)[https://pkg.go.dev/golang.org/x/sys/cpu] package to
check dynamically for these features.
Example Usage
The following benchmarks demonstrate summing an array of 8192 values using various optimizations.
Disable no architecture optimizations (thus using AVX2):
$ INTEL_DISABLE_EXT=NONE go test -bench=8192 -run=. ./math
goos: darwin
goarch: amd64
pkg: github.com/apache/arrow-go/arrow/math
BenchmarkFloat64Funcs_Sum_8192-8 2000000 687 ns/op 95375.41 MB/s
BenchmarkInt64Funcs_Sum_8192-8 2000000 719 ns/op 91061.06 MB/s
BenchmarkUint64Funcs_Sum_8192-8 2000000 691 ns/op 94797.29 MB/s
PASS
ok github.com/apache/arrow-go/arrow/math 6.444s
NOTE: NONE
is simply ignored, thus enabling optimizations for AVX2 and SSE4
Disable AVX2 architecture optimizations:
$ INTEL_DISABLE_EXT=AVX2 go test -bench=8192 -run=. ./math
goos: darwin
goarch: amd64
pkg: github.com/apache/arrow-go/arrow/math
BenchmarkFloat64Funcs_Sum_8192-8 1000000 1912 ns/op 34263.63 MB/s
BenchmarkInt64Funcs_Sum_8192-8 1000000 1392 ns/op 47065.57 MB/s
BenchmarkUint64Funcs_Sum_8192-8 1000000 1405 ns/op 46636.41 MB/s
PASS
ok github.com/apache/arrow-go/arrow/math 4.786s
Disable ALL architecture optimizations, thus using pure Go implementation:
$ INTEL_DISABLE_EXT=ALL go test -bench=8192 -run=. ./math
goos: darwin
goarch: amd64
pkg: github.com/apache/arrow-go/arrow/math
BenchmarkFloat64Funcs_Sum_8192-8 200000 10285 ns/op 6371.41 MB/s
BenchmarkInt64Funcs_Sum_8192-8 500000 3892 ns/op 16837.37 MB/s
BenchmarkUint64Funcs_Sum_8192-8 500000 3929 ns/op 16680.00 MB/s
PASS
ok github.com/apache/arrow-go/arrow/math 6.179s