lmdb: use md5 hash of arbitrary tag value + reindex everything again.

lmdb/delete.go

@@ -3,20 +3,16 @@ package lmdb
 import (
 	"context"
 	"encoding/hex"
+	"fmt"
 
 	"github.com/PowerDNS/lmdb-go/lmdb"
 	"github.com/nbd-wtf/go-nostr"
 )
 
 func (b *LMDBBackend) DeleteEvent(ctx context.Context, evt *nostr.Event) error {
-	err := b.lmdbEnv.Update(func(txn *lmdb.Txn) error {
+	return b.lmdbEnv.Update(func(txn *lmdb.Txn) error {
 		return b.delete(txn, evt)
 	})
-	if err != nil {
-		return err
-	}
-
-	return nil
 }
 
 func (b *LMDBBackend) delete(txn *lmdb.Txn, evt *nostr.Event) error {
@@ -27,17 +23,21 @@ func (b *LMDBBackend) delete(txn *lmdb.Txn, evt *nostr.Event) error {
 		return nil
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get current idx for deleting %x: %w", evt.ID[0:8*2], err)
 	}
 
 	// calculate all index keys we have for this event and delete them
 	for k := range b.getIndexKeysForEvent(evt) {
 		err := txn.Del(k.dbi, k.key, idx)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to delete index entry %s for %x: %w", b.keyName(k), evt.ID[0:8*2], err)
 		}
 	}
 
 	// delete the raw event
-	return txn.Del(b.rawEventStore, idx, nil)
+	if err := txn.Del(b.rawEventStore, idx, nil); err != nil {
+		return fmt.Errorf("failed to delete raw event %x (idx %x): %w", evt.ID[0:8*2], idx, err)
+	}
+
+	return nil
 }

lmdb/helpers.go

@@ -1,6 +1,7 @@
 package lmdb
 
 import (
+	"crypto/md5"
 	"encoding/binary"
 	"encoding/hex"
 	"fmt"
@@ -169,13 +170,15 @@ func (b *LMDBBackend) getTagIndexPrefix(tagValue string) (lmdb.DBI, []byte, int)
 		}
 	}
 
-	// index whatever else as utf-8, but limit it to 40 bytes
-	k = make([]byte, 40+4)
-	n := copy(k[0:40], tagValue)
-	offset = n
+	// index whatever else as a md5 hash of the contents
+	h := md5.New()
+	h.Write([]byte(tagValue))
+	k = make([]byte, 0, 16+4)
+	k = h.Sum(k)
+	offset = 16
 	dbi = b.indexTag
 
-	return dbi, k[0 : n+4], offset
+	return dbi, k[0 : 16+4], offset
 }
 
 func (b *LMDBBackend) dbiName(dbi lmdb.DBI) string {

lmdb/migration.go

@@ -54,8 +54,8 @@ func (b *LMDBBackend) runMigrations() error {
 		//
 
 		// this is when we reindex everything
-		if version < 7 {
-			log.Println("[lmdb] migration 7: reindex everything")
+		if version < 8 {
+			log.Println("[lmdb] migration 8: reindex everything")
 
 			if err := txn.Drop(b.indexId, false); err != nil {
 				return err
@@ -87,7 +87,7 @@ func (b *LMDBBackend) runMigrations() error {
 
 			cursor, err := txn.OpenCursor(b.rawEventStore)
 			if err != nil {
-				return fmt.Errorf("failed to open cursor in migration 7: %w", err)
+				return fmt.Errorf("failed to open cursor in migration 8: %w", err)
 			}
 			defer cursor.Close()
 
@@ -116,7 +116,7 @@ func (b *LMDBBackend) runMigrations() error {
 
 				for key := range b.getIndexKeysForEvent(evt) {
 					if err := txn.Put(key.dbi, key.key, idx, 0); err != nil {
-						return fmt.Errorf("failed to save index %s for event %s (%v) on migration 7: %w",
+						return fmt.Errorf("failed to save index %s for event %s (%v) on migration 8: %w",
 							b.keyName(key), evt.ID, idx, err)
 					}
 				}
@@ -130,7 +130,7 @@ func (b *LMDBBackend) runMigrations() error {
 			}
 
 			// bump version
-			if err := b.setVersion(txn, 7); err != nil {
+			if err := b.setVersion(txn, 8); err != nil {
 				return err
 			}
 		}