Use PathLength

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteRemoteDocumentCache.java

@@ -63,10 +63,10 @@ public void add(MutableDocument document, SnapshotVersion readTime) {
 
     db.execute(
         "INSERT OR REPLACE INTO remote_documents "
-            + "(path, parent_path, read_time_seconds, read_time_nanos, contents) "
+            + "(path, path_length, read_time_seconds, read_time_nanos, contents) "
             + "VALUES (?, ?, ?, ?, ?)",
         EncodedPath.encode(documentKey.getPath()),
-        EncodedPath.encode(documentKey.getCollectionPath()),
+        documentKey.getPath().length(),
         timestamp.getSeconds(),
         timestamp.getNanoseconds(),
         message.toByteArray());
@@ -135,69 +135,73 @@ public ImmutableSortedMap<DocumentKey, MutableDocument> getAllDocumentsMatchingQ
         !query.isCollectionGroupQuery(),
         "CollectionGroup queries should be handled in LocalDocumentsView");
 
-    String parentPath = EncodedPath.encode(query.getPath());
-    BackgroundQueue backgroundQueue = new BackgroundQueue();
+    StringBuilder sql =
+        new StringBuilder(
+            "SELECT contents, read_time_seconds, read_time_nanos "
+                + "FROM remote_documents WHERE path >= ? AND path < ? AND path_length = ?");
 
-    ImmutableSortedMap<DocumentKey, MutableDocument>[] matchingDocuments =
-        (ImmutableSortedMap<DocumentKey, MutableDocument>[])
-            new ImmutableSortedMap[] {DocumentCollections.emptyMutableDocumentMap()};
+    Object[] bindVars = new Object[3 + (FieldIndex.IndexOffset.NONE.equals(offset) ? 0 : 6)];
 
-    SQLitePersistence.Query sqlQuery;
-    if (FieldIndex.IndexOffset.NONE.equals(offset)) {
-      sqlQuery =
-          db.query(
-                  "SELECT contents, read_time_seconds, read_time_nanos "
-                      + "FROM remote_documents WHERE parent_path = ?")
-              .binding(parentPath);
-    } else {
+    String prefix = EncodedPath.encode(query.getPath());
+
+    int i = 0;
+    bindVars[i++] = prefix;
+    bindVars[i++] = EncodedPath.prefixSuccessor(prefix);
+    bindVars[i++] = query.getPath().length() + 1;
+
+    if (!FieldIndex.IndexOffset.NONE.equals(offset)) {
       Timestamp readTime = offset.getReadTime().getTimestamp();
       DocumentKey documentKey = offset.getDocumentKey();
 
-      sqlQuery =
-          db.query(
-                  "SELECT contents, read_time_seconds, read_time_nanos "
-                      + "FROM remote_documents WHERE parent_path = ? AND ("
-                      + "read_time_seconds > ? OR ("
-                      + "read_time_seconds = ? AND read_time_nanos > ?) OR ("
-                      + "read_time_seconds = ? AND read_time_nanos = ? and path > ?))")
-              .binding(
-                  parentPath,
-                  readTime.getSeconds(),
-                  readTime.getSeconds(),
-                  readTime.getNanoseconds(),
-                  readTime.getSeconds(),
-                  readTime.getNanoseconds(),
-                  EncodedPath.encode(documentKey.getPath()));
+      sql.append(
+          " AND (read_time_seconds > ? OR ("
+              + "read_time_seconds = ? AND read_time_nanos > ?) OR ("
+              + "read_time_seconds = ? AND read_time_nanos = ? and path > ?))");
+      bindVars[i++] = readTime.getSeconds();
+      bindVars[i++] = readTime.getSeconds();
+      bindVars[i++] = readTime.getNanoseconds();
+      bindVars[i++] = readTime.getSeconds();
+      bindVars[i++] = readTime.getNanoseconds();
+      bindVars[i] = EncodedPath.encode(documentKey.getPath());
     }
-    sqlQuery.forEach(
-        row -> {
-          // Store row values in array entries to provide the correct context inside the executor.
-          final byte[] rawDocument = row.getBlob(0);
-          final int[] readTimeSeconds = {row.getInt(1)};
-          final int[] readTimeNanos = {row.getInt(2)};
-
-          // Since scheduling background tasks incurs overhead, we only dispatch to a
-          // background thread if there are still some documents remaining.
-          Executor executor = row.isLast() ? Executors.DIRECT_EXECUTOR : backgroundQueue;
-          executor.execute(
-              () -> {
-                MutableDocument document =
-                    decodeMaybeDocument(rawDocument, readTimeSeconds[0], readTimeNanos[0]);
-                if (document.isFoundDocument() && query.matches(document)) {
-                  synchronized (SQLiteRemoteDocumentCache.this) {
-                    matchingDocuments[0] = matchingDocuments[0].insert(document.getKey(), document);
-                  }
-                }
-              });
-        });
+
+    ImmutableSortedMap<DocumentKey, MutableDocument>[] results =
+        (ImmutableSortedMap<DocumentKey, MutableDocument>[])
+            new ImmutableSortedMap[] {DocumentCollections.emptyMutableDocumentMap()};
+    BackgroundQueue backgroundQueue = new BackgroundQueue();
+
+    db.query(sql.toString())
+        .binding(bindVars)
+        .forEach(
+            row -> {
+              // Store row values in array entries to provide the correct context inside the
+              // executor.
+              final byte[] rawDocument = row.getBlob(0);
+              final int[] readTimeSeconds = {row.getInt(1)};
+              final int[] readTimeNanos = {row.getInt(2)};
+
+              // Since scheduling background tasks incurs overhead, we only dispatch to a
+              // background thread if there are still some documents remaining.
+              Executor executor = row.isLast() ? Executors.DIRECT_EXECUTOR : backgroundQueue;
+              executor.execute(
+                  () -> {
+                    MutableDocument document =
+                        decodeMaybeDocument(rawDocument, readTimeSeconds[0], readTimeNanos[0]);
+                    if (document.isFoundDocument() && query.matches(document)) {
+                      synchronized (SQLiteRemoteDocumentCache.this) {
+                        results[0] = results[0].insert(document.getKey(), document);
+                      }
+                    }
+                  });
+            });
 
     try {
       backgroundQueue.drain();
     } catch (InterruptedException e) {
       fail("Interrupted while deserializing documents", e);
     }
 
-    return matchingDocuments[0];
+    return results[0];
   }
 
   @Override

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteSchema.java

@@ -174,8 +174,8 @@ void runSchemaUpgrades(int fromVersion, int toVersion) {
     }
 
     if (fromVersion < 13 && toVersion >= 13) {
-      addParentPath();
-      ensureParentPath();
+      addPathLength();
+      ensurePathLength();
     }
 
     /*
@@ -447,10 +447,10 @@ private void addSequenceNumber() {
     }
   }
 
-  private void addParentPath() {
-    if (!tableContainsColumn("remote_documents", "parent_path")) {
-      db.execSQL("ALTER TABLE remote_documents ADD COLUMN parent_path TEXT");
-      db.execSQL("CREATE INDEX parent_path_index ON remote_documents(parent_path)");
+  private void addPathLength() {
+    if (!tableContainsColumn("remote_documents", "path_length")) {
+      // The "path_length" column store the number of segments in the path.
+      db.execSQL("ALTER TABLE remote_documents ADD COLUMN path_length INTEGER");
     }
   }
 
@@ -629,14 +629,14 @@ private void rewriteCanonicalIds() {
             });
   }
 
-  /** Fill the remote_document's parent path column. */
-  private void ensureParentPath() {
+  /** Fill the remote_document's path_length column. */
+  private void ensurePathLength() {
     SQLitePersistence.Query documentsToMigrate =
         new SQLitePersistence.Query(
-                db, "SELECT path FROM remote_documents WHERE parent_path IS NULL LIMIT ?")
+                db, "SELECT path FROM remote_documents WHERE path_length IS NULL LIMIT ?")
             .binding(MIGRATION_BATCH_SIZE);
     SQLiteStatement insertKey =
-        db.compileStatement("UPDATE remote_documents SET parent_path = ? WHERE path = ?");
+        db.compileStatement("UPDATE remote_documents SET path_length = ? WHERE path = ?");
 
     boolean[] resultsRemaining = new boolean[1];
 
@@ -651,7 +651,7 @@ private void ensureParentPath() {
             ResourcePath decodedPath = EncodedPath.decodeResourcePath(encodedPath);
 
             insertKey.clearBindings();
-            insertKey.bindString(1, EncodedPath.encode(decodedPath.popLast()));
+            insertKey.bindLong(1, decodedPath.length());
             insertKey.bindString(2, encodedPath);
             hardAssert(insertKey.executeUpdateDelete() != -1, "Failed to update document path");
           });

firebase-firestore/src/test/java/com/google/firebase/firestore/local/SQLiteSchemaTest.java

@@ -578,10 +578,10 @@ public void rewritesCanonicalIds() {
   }
 
   @Test
-  public void addParentPaths() {
+  public void addPathLengths() {
     schema.runSchemaUpgrades(0, 12);
 
-    ResourcePath paths[] = new ResourcePath[] {path("collA/doc"), path("collB/doc")};
+    ResourcePath paths[] = new ResourcePath[] {path("collA/doc"), path("collA/doc/collB/doc")};
 
     for (ResourcePath path : paths) {
       db.execSQL(
@@ -592,18 +592,17 @@ public void addParentPaths() {
     schema.runSchemaUpgrades(12, 13);
 
     int[] current = new int[] {0};
-    new SQLitePersistence.Query(db, "SELECT parent_path FROM remote_documents ORDER BY path")
+    new SQLitePersistence.Query(db, "SELECT path_length FROM remote_documents ORDER BY path")
         .forEach(
             cursor -> {
-              ResourcePath parentPath = EncodedPath.decodeResourcePath(cursor.getString(0));
-              assertEquals(paths[current[0]].popLast(), parentPath);
+              assertEquals(paths[current[0]].length(), cursor.getInt(0));
               ++current[0];
             });
     assertEquals(2, current[0]);
   }
 
   @Test
-  public void usesMultipleBatchesToAddParentPaths() {
+  public void usesMultipleBatchesToAddPathLengths() {
     schema.runSchemaUpgrades(0, 12);
 
     for (int i = 0; i < SQLiteSchema.MIGRATION_BATCH_SIZE + 1; ++i) {
@@ -616,11 +615,10 @@ public void usesMultipleBatchesToAddParentPaths() {
     schema.runSchemaUpgrades(12, 13);
 
     int[] current = new int[] {0};
-    new SQLitePersistence.Query(db, "SELECT parent_path FROM remote_documents ORDER by path")
+    new SQLitePersistence.Query(db, "SELECT path_length FROM remote_documents ORDER by path")
         .forEach(
             cursor -> {
-              ResourcePath parentPath = EncodedPath.decodeResourcePath(cursor.getString(0));
-              assertEquals(path("coll"), parentPath);
+              assertEquals(2, cursor.getInt(0));
               ++current[0];
             });
     assertEquals(SQLiteSchema.MIGRATION_BATCH_SIZE + 1, current[0]);