restic/internal/repository/master_index_test.go
Matthew Dawson df2c03a6a4
repository/master_index: Optimize Index.Lookup()
When looking up a blob in the master index, with several
indexes present in the master index, a significant amount of time
is spent generating errors for each failed lookup.  However, these
errors are often used to check if a blob is present, but the contents
are not inspected making the overhead of the error not useful.

Instead, change Index.Lookup (and Index.LookupSize) to instead return
a boolean denoting if the blob was found instead of an error.  Also change
all the calls to these functions to handle the new function signature.

benchmark                                            old ns/op     new ns/op     delta
BenchmarkMasterIndexLookupSingleIndex-6              820           897           +9.39%
BenchmarkMasterIndexLookupMultipleIndex-6            12821         2001          -84.39%
BenchmarkMasterIndexLookupSingleIndexUnknown-6       5378          492           -90.85%
BenchmarkMasterIndexLookupMultipleIndexUnknown-6     17026         1649          -90.31%

benchmark                                            old allocs     new allocs     delta
BenchmarkMasterIndexLookupSingleIndex-6              9              9              +0.00%
BenchmarkMasterIndexLookupMultipleIndex-6            59             19             -67.80%
BenchmarkMasterIndexLookupSingleIndexUnknown-6       22             6              -72.73%
BenchmarkMasterIndexLookupMultipleIndexUnknown-6     72             16             -77.78%

benchmark                                            old bytes     new bytes     delta
BenchmarkMasterIndexLookupSingleIndex-6              160           160           +0.00%
BenchmarkMasterIndexLookupMultipleIndex-6            3200          240           -92.50%
BenchmarkMasterIndexLookupSingleIndexUnknown-6       1232          48            -96.10%
BenchmarkMasterIndexLookupMultipleIndexUnknown-6     4272          128           -97.00%
2018-01-23 22:25:56 -05:00

123 lines
2.8 KiB
Go

package repository_test
import (
"math/rand"
"testing"
"github.com/restic/restic/internal/repository"
"github.com/restic/restic/internal/restic"
rtest "github.com/restic/restic/internal/test"
)
func TestMasterIndexLookup(t *testing.T) {
idInIdx1 := restic.NewRandomID()
idInIdx2 := restic.NewRandomID()
blob1 := restic.PackedBlob{
PackID: restic.NewRandomID(),
Blob: restic.Blob{
Type: restic.DataBlob,
ID: idInIdx1,
Length: 10,
Offset: 0,
},
}
blob2 := restic.PackedBlob{
PackID: restic.NewRandomID(),
Blob: restic.Blob{
Type: restic.DataBlob,
ID: idInIdx2,
Length: 100,
Offset: 10,
},
}
idx1 := repository.NewIndex()
idx1.Store(blob1)
idx2 := repository.NewIndex()
idx2.Store(blob2)
mIdx := repository.NewMasterIndex()
mIdx.Insert(idx1)
mIdx.Insert(idx2)
blobs, found := mIdx.Lookup(idInIdx1, restic.DataBlob)
rtest.Assert(t, found, "Expected to find blob id %v from index 1", idInIdx1)
rtest.Equals(t, []restic.PackedBlob{blob1}, blobs)
blobs, found = mIdx.Lookup(idInIdx2, restic.DataBlob)
rtest.Assert(t, found, "Expected to find blob id %v from index 2", idInIdx2)
rtest.Equals(t, []restic.PackedBlob{blob2}, blobs)
blobs, found = mIdx.Lookup(restic.NewRandomID(), restic.DataBlob)
rtest.Assert(t, !found, "Expected to not find a blob when fetching with a random id")
rtest.Assert(t, blobs == nil, "Expected no blobs when fetching with a random id")
}
func BenchmarkMasterIndexLookupSingleIndex(b *testing.B) {
idx1, lookupID := createRandomIndex(rand.New(rand.NewSource(0)))
mIdx := repository.NewMasterIndex()
mIdx.Insert(idx1)
b.ResetTimer()
for i := 0; i < b.N; i++ {
mIdx.Lookup(lookupID, restic.DataBlob)
}
}
func BenchmarkMasterIndexLookupMultipleIndex(b *testing.B) {
rng := rand.New(rand.NewSource(0))
mIdx := repository.NewMasterIndex()
for i := 0; i < 5; i++ {
idx, _ := createRandomIndex(rand.New(rng))
mIdx.Insert(idx)
}
idx1, lookupID := createRandomIndex(rand.New(rng))
mIdx.Insert(idx1)
b.ResetTimer()
for i := 0; i < b.N; i++ {
mIdx.Lookup(lookupID, restic.DataBlob)
}
}
func BenchmarkMasterIndexLookupSingleIndexUnknown(b *testing.B) {
lookupID := restic.NewRandomID()
idx1, _ := createRandomIndex(rand.New(rand.NewSource(0)))
mIdx := repository.NewMasterIndex()
mIdx.Insert(idx1)
b.ResetTimer()
for i := 0; i < b.N; i++ {
mIdx.Lookup(lookupID, restic.DataBlob)
}
}
func BenchmarkMasterIndexLookupMultipleIndexUnknown(b *testing.B) {
rng := rand.New(rand.NewSource(0))
lookupID := restic.NewRandomID()
mIdx := repository.NewMasterIndex()
for i := 0; i < 5; i++ {
idx, _ := createRandomIndex(rand.New(rng))
mIdx.Insert(idx)
}
idx1, _ := createRandomIndex(rand.New(rng))
mIdx.Insert(idx1)
b.ResetTimer()
for i := 0; i < b.N; i++ {
mIdx.Lookup(lookupID, restic.DataBlob)
}
}