tool: fix db scan crash, add tests

`db scan` crashes when the database uses columnar blocks because it
incorrectly does a `SeekGE(nil)`. This commit fixes this and adds some
fixtures and tests with CRDB schema.

Author: RaduBerinde

tool/data_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/cockroachdb/datadriven"
 	"github.com/cockroachdb/errors"
 	"github.com/cockroachdb/pebble"
+	"github.com/cockroachdb/pebble/cockroachkvs"
 	"github.com/cockroachdb/pebble/internal/base"
 	"github.com/cockroachdb/pebble/internal/testkeys"
 	"github.com/cockroachdb/pebble/vfs"
@@ -132,10 +133,12 @@ func runTests(t *testing.T, path string) {
 
 				tool := New(
 					DefaultComparer(comparer),
-					Comparers(altComparer, testkeys.Comparer),
+					Comparers(altComparer, testkeys.Comparer, &cockroachkvs.Comparer),
 					Mergers(merger),
 					FS(fs),
 					OpenErrEnhancer(openErrEnhancer),
+					KeySchema(cockroachkvs.KeySchema.Name),
+					KeySchemas(&cockroachkvs.KeySchema),
 				)
 
 				c := &cobra.Command{}

tool/db.go

@@ -527,7 +527,13 @@ func (d *dbT) runScan(cmd *cobra.Command, args []string) {
 	iter, _ := db.NewIter(&pebble.IterOptions{
 		UpperBound: d.end,
 	})
-	for valid := iter.SeekGE(d.start); valid; valid = iter.Next() {
+	var valid bool
+	if len(d.start) == 0 {
+		valid = iter.First()
+	} else {
+		valid = iter.SeekGE(d.start)
+	}
+	for ; valid; valid = iter.Next() {
 		if fmtKeys || fmtValues {
 			needDelimiter := false
 			if fmtKeys {

tool/make_test_sstables.go

@@ -9,24 +9,28 @@ package main
 
 import (
 	"log"
+	"math/rand/v2"
 
-	"github.com/cockroachdb/pebble/internal/private"
+	"github.com/cockroachdb/pebble/cockroachkvs"
+	"github.com/cockroachdb/pebble/internal/sstableinternal"
 	"github.com/cockroachdb/pebble/objstorage/objstorageprovider"
 	"github.com/cockroachdb/pebble/sstable"
 	"github.com/cockroachdb/pebble/vfs"
 )
 
-func makeOutOfOrder() {
+func makeOutOfOrderSST() {
 	fs := vfs.Default
-	f, err := fs.Create("tool/testdata/out-of-order.sst")
+	f, err := fs.Create("tool/testdata/out-of-order.sst", vfs.WriteCategoryUnspecified)
 	if err != nil {
 		log.Fatal(err)
 	}
 	opts := sstable.WriterOptions{
 		TableFormat: sstable.TableFormatPebblev1,
 	}
+	opts.SetInternal(sstableinternal.WriterOptions{
+		DisableKeyOrderChecks: true,
+	})
 	w := sstable.NewWriter(objstorageprovider.NewFileWritable(f), opts)
-	private.SSTableWriterDisableKeyOrderChecks(w)
 
 	set := func(key string) {
 		if err := w.Set([]byte(key), nil); err != nil {
@@ -43,6 +47,48 @@ func makeOutOfOrder() {
 	}
 }
 
+func makeCockroachSchemaSST() {
+	fs := vfs.Default
+	f, err := fs.Create("tool/testdata/cr-schema.sst", vfs.WriteCategoryUnspecified)
+	if err != nil {
+		log.Fatal(err)
+	}
+	opts := sstable.WriterOptions{
+		TableFormat: sstable.TableFormatMax,
+		Comparer:    &cockroachkvs.Comparer,
+		KeySchema:   &cockroachkvs.KeySchema,
+		BlockSize:   32,
+	}
+	w := sstable.NewWriter(objstorageprovider.NewFileWritable(f), opts)
+
+	//	2025/04/03 15:38:23 background error: pebble: keys must be added in strictly increasing order:
+	//   tcestilr\x00\x00\x00\x00\x1a5\xaddx\x09#20,SET
+	//   tcestilr\x00\x00\x00\x01\xc8\xc0@\xe4%\x09#19,SET
+
+	cfg := cockroachkvs.KeyGenConfig{
+		PrefixAlphabetLen:  20,
+		PrefixLenShared:    2,
+		RoachKeyLen:        8,
+		AvgKeysPerPrefix:   2,
+		BaseWallTime:       1,
+		PercentLogical:     10,
+		PercentEmptySuffix: 5,
+		PercentLockSuffix:  5,
+	}
+	rng := rand.New(rand.NewPCG(1, 1))
+	keys, vals := cockroachkvs.RandomKVs(rng, 20, cfg, 16)
+
+	for i := range keys {
+		if err := w.Set(keys[i], vals[i]); err != nil {
+			log.Fatal(err)
+		}
+	}
+	if err := w.Close(); err != nil {
+		log.Fatal(err)
+	}
+}
+
 func main() {
-	makeOutOfOrder()
+	makeOutOfOrderSST()
+	makeCockroachSchemaSST()
 }

tool/testdata/cr-schema-db/000002.log

@@ -0,0 +1,55 @@
+[Version]
+  pebble_version=0.1
+
+[Options]
+  bytes_per_sync=524288
+  cache_size=8388608
+  cleaner=delete
+  compaction_debt_concurrency=1073741824
+  comparer=cockroach_comparator
+  disable_wal=false
+  flush_delay_delete_range=0s
+  flush_delay_range_key=0s
+  flush_split_bytes=4194304
+  format_major_version=20
+  key_schema=crdb1
+  l0_compaction_concurrency=10
+  l0_compaction_file_threshold=500
+  l0_compaction_threshold=4
+  l0_stop_writes_threshold=12
+  lbase_max_bytes=67108864
+  max_concurrent_compactions=1
+  max_concurrent_downloads=1
+  max_manifest_file_size=134217728
+  max_open_files=1000
+  mem_table_size=4194304
+  mem_table_stop_writes_threshold=2
+  min_deletion_rate=0
+  free_space_threshold_bytes=17179869184
+  free_space_timeframe=10s
+  obsolete_bytes_max_ratio=0.200000
+  obsolete_bytes_timeframe=5m0s
+  merger=pebble.concatenate
+  multilevel_compaction_heuristic=wamp(0.00, false)
+  read_compaction_rate=16000
+  read_sampling_multiplier=16
+  num_deletions_threshold=100
+  deletion_size_ratio_threshold=0.500000
+  tombstone_dense_compaction_threshold=0.100000
+  strict_wal_tail=true
+  table_cache_shards=10
+  validate_on_ingest=false
+  wal_dir=
+  wal_bytes_per_sync=0
+  secondary_cache_size_bytes=0
+  create_on_shared=0
+
+[Level "0"]
+  block_restart_interval=16
+  block_size=4096
+  block_size_threshold=90
+  compression=Snappy
+  filter_policy=none
+  filter_type=table
+  index_block_size=4096
+  target_file_size=2097152