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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,75 @@ | ||
| // Copyright 2024 Dolthub, Inc. | ||
| // | ||
| // Licensed 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. | ||
|
|
||
| package admin | ||
|
|
||
| import ( | ||
| "context" | ||
|
|
||
| "github.com/dolthub/dolt/go/cmd/dolt/cli" | ||
| "github.com/dolthub/dolt/go/libraries/doltcore/doltdb" | ||
| "github.com/dolthub/dolt/go/libraries/doltcore/env" | ||
| "github.com/dolthub/dolt/go/libraries/utils/argparser" | ||
| "github.com/dolthub/dolt/go/store/datas" | ||
| "github.com/dolthub/dolt/go/store/nbs" | ||
| ) | ||
|
|
||
| type DeltaCmd struct { | ||
| } | ||
|
|
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| func (cmd DeltaCmd) Name() string { | ||
| return "delta" | ||
| } | ||
|
|
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| // Description returns a description of the command | ||
| func (cmd DeltaCmd) Description() string { | ||
| return "walks history and prints possible space savings with delta encoding" | ||
| } | ||
| func (cmd DeltaCmd) RequiresRepo() bool { | ||
| return true | ||
| } | ||
| func (cmd DeltaCmd) Docs() *cli.CommandDocumentation { | ||
| return nil | ||
| } | ||
|
|
||
| func (cmd DeltaCmd) ArgParser() *argparser.ArgParser { | ||
| ap := argparser.NewArgParserWithMaxArgs(cmd.Name(), 0) | ||
| return ap | ||
| } | ||
| func (cmd DeltaCmd) Hidden() bool { | ||
| return true | ||
| } | ||
|
|
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| func (cmd DeltaCmd) Exec(ctx context.Context, commandStr string, args []string, dEnv *env.DoltEnv, cliCtx cli.CliContext) int { | ||
| // ap := cmd.ArgParser() | ||
| // usage, _ := cli.HelpAndUsagePrinters(cli.CommandDocsForCommandString(commandStr, cli.CommandDocumentationContent{}, ap)) | ||
| // cli.ParseArgsOrDie(ap, args, usage) | ||
| db := doltdb.HackDatasDatabaseFromDoltDB(dEnv.DoltDB) | ||
| cs := datas.ChunkStoreFromDatabase(db) | ||
| if _, ok := cs.(*nbs.GenerationalNBS); !ok { | ||
| cli.PrintErrln("Delta command requires a GenerationalNBS") | ||
| return 1 | ||
| } | ||
|
|
||
| err := nbs.RunExperiment(cs, func(format string, args ...interface{}) { | ||
| cli.Printf(format, args...) | ||
| }) | ||
|
|
||
| if err != nil { | ||
| cli.PrintErrln(err) | ||
| return 1 | ||
| } | ||
|
|
||
| return 0 | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,155 @@ | ||
| // Copyright 2024 Dolthub, Inc. | ||
| // | ||
| // Licensed 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. | ||
|
|
||
| package nbs | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
|
|
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| "github.com/balacode/go-delta" | ||
| "github.com/dolthub/dolt/go/store/chunks" | ||
| ) | ||
|
|
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| const deltaPrefixLen = 16 | ||
|
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| type bprefix [deltaPrefixLen]byte | ||
|
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| type addrBytes struct { | ||
| a addr | ||
| b []byte | ||
| } | ||
|
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| type PrintfFunc func(format string, args ...interface{}) | ||
|
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| func RunExperiment(cs chunks.ChunkStore, p PrintfFunc) error { | ||
| if gs, ok := cs.(*GenerationalNBS); ok { | ||
| oldgen := gs.oldGen.tables.upstream | ||
|
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| prefixMap := make(map[bprefix][]addrBytes) | ||
|
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| uncompressedTotal := uint64(0) | ||
| for tf, cs := range oldgen { | ||
| p("table file: %s\n", tf.String()) | ||
|
|
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| idx, err := cs.index() | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
|
|
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| largeChunks := 0 | ||
| for i := uint32(0); i < idx.chunkCount(); i++ { | ||
| var a addr | ||
| _, err := idx.indexEntry(i, &a) | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
| var stat Stats | ||
| bytes, err := cs.get(context.TODO(), a, &stat) | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
|
|
||
| if len(bytes) > 512 { // NM4 - try other values? Smaller? Bigger? | ||
| prefix := bprefix(bytes[2 : deltaPrefixLen+2]) | ||
| prefixMap[prefix] = append(prefixMap[prefix], addrBytes{a, bytes}) | ||
| largeChunks++ | ||
| } else { | ||
| uncompressedTotal += uint64(len(bytes)) | ||
| } | ||
| } | ||
|
|
||
| progress := 0 | ||
| sumSaved := uint64(0) | ||
| for pfx, group := range prefixMap { | ||
| total, saved := biteSizeEvaluate(group, .75) | ||
| progress += len(group) | ||
| p("Group: %v (%d/%d chunks) saved: %d of %d\n", pfx, progress, largeChunks, saved, total) | ||
| sumSaved += saved | ||
| uncompressedTotal += total | ||
| } | ||
|
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| savings := 100.0 * (1.0 - float64(uncompressedTotal-sumSaved)/float64(uncompressedTotal)) | ||
| p("Total saved: %d of %d (%.2f%% reduction)\n", sumSaved, uncompressedTotal, savings) | ||
| } | ||
|
|
||
| } else { | ||
| panic(fmt.Sprintf("Use a modern db brah")) | ||
| } | ||
|
|
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| return nil | ||
| } | ||
|
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| func biteSizeEvaluate(group []addrBytes, threshold float64) (uncompressedTotal, saved uint64) { | ||
| if len(group) < 100 { | ||
| return bruteForceGroup(group, threshold) | ||
| } else { | ||
| mid := len(group) / 2 | ||
|
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| uncompressedTotal, saved = biteSizeEvaluate(group[:mid], threshold) | ||
|
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| uncompressedTotal2, saved2 := biteSizeEvaluate(group[mid:], threshold) | ||
|
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| uncompressedTotal += uncompressedTotal2 | ||
| saved += saved2 | ||
|
|
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| return | ||
| } | ||
| } | ||
|
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| type savings struct { | ||
| src addr | ||
| dst addr | ||
| bytesSaved uint64 | ||
| ratio float64 | ||
| } | ||
|
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| func bruteForceGroup(group []addrBytes, threshold float64) (uncompressedTotal, saved uint64) { | ||
| bestSavings := make(map[int]savings) | ||
| for srcIndx, src := range group { | ||
| uncompressedTotal += uint64(len(src.b)) | ||
| for dstIndx, dst := range group[srcIndx+1:] { | ||
| dif := delta.Make(src.b, dst.b) | ||
| difBytes := dif.Bytes() | ||
|
|
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| // NM4 - 64 is arbitrary. Based on the diff, it's probably not worth the compute time to store as a delta. | ||
| if len(difBytes)+64 < len(dst.b) { | ||
| deltaRatio := float64(len(difBytes)) / float64(len(dst.b)) | ||
|
|
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| if deltaRatio <= threshold { | ||
| // NM4 - 32 is a guess of the bytes for the address + other serialization overhead | ||
| s := savings{src.a, dst.a, uint64(len(dst.b) - len(difBytes) - 32), deltaRatio} | ||
|
|
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| if best, ok := bestSavings[srcIndx]; !ok || s.bytesSaved > best.bytesSaved { | ||
| bestSavings[srcIndx+dstIndx] = s | ||
| } | ||
|
|
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| /* | ||
| p("Source: %d bytes\n", len(src.b)) | ||
| p("Destination: %d bytes\n", len(dst.b)) | ||
| p("Delta: %d bytes\n", len(difBytes)) | ||
| p("Total: %d bytes raw vs %d bytes delta compressed (%f)\n", totalBytes, compressedBytes, deltaRatio) | ||
| */ | ||
| } | ||
| } | ||
|
|
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| } | ||
|
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| srcSavings, ok := bestSavings[srcIndx] | ||
| if ok { | ||
| saved += srcSavings.bytesSaved | ||
| } | ||
| } | ||
| return | ||
| } |