Optimization: skip checking for bucket_parameters changes if there are

none.

Author: rkistner

modules/module-mongodb-storage/src/storage/implementation/MongoSyncBucketStorage.ts

@@ -9,6 +9,7 @@ import {
 } from '@powersync/lib-services-framework';
 import {
   BroadcastIterable,
+  CHECKPOINT_INVALIDATE_ALL,
   CheckpointChanges,
   GetCheckpointChangesOptions,
   getLookupBucketDefinitionName,
@@ -884,6 +885,7 @@ export class MongoSyncBucketStorage
   private async getParameterBucketChanges(
     options: GetCheckpointChangesOptions
   ): Promise<Pick<CheckpointChanges, 'updatedParameterBucketDefinitions' | 'invalidateParameterBuckets'>> {
+    // TODO: limit max query running time
     const parameterUpdates = await this.db.bucket_parameters
       .find(
         {
@@ -910,6 +912,9 @@ export class MongoSyncBucketStorage
     };
   }
 
+  // TODO:
+  // We can optimize this by implementing it like ChecksumCache: We can use partial cache results to do
+  // more efficient lookups in some cases.
   private checkpointChangesCache = new LRUCache<string, CheckpointChanges, { options: GetCheckpointChangesOptions }>({
     max: 50,
     maxSize: 10 * 1024 * 1024,
@@ -921,7 +926,31 @@ export class MongoSyncBucketStorage
     }
   });
 
+  private _hasDynamicBucketsCached: boolean | undefined = undefined;
+
+  private hasDynamicBucketQueries(): boolean {
+    if (this._hasDynamicBucketsCached != null) {
+      return this._hasDynamicBucketsCached;
+    }
+    const syncRules = this.getParsedSyncRules({
+      defaultSchema: 'default' // n/a
+    });
+    const hasDynamicBuckets = syncRules.hasDynamicBucketQueries();
+    this._hasDynamicBucketsCached = hasDynamicBuckets;
+    return hasDynamicBuckets;
+  }
+
   async getCheckpointChanges(options: GetCheckpointChangesOptions): Promise<CheckpointChanges> {
+    if (!this.hasDynamicBucketQueries()) {
+      // Special case when we have no dynamic parameter queries.
+      // In this case, we can avoid doing any queries.
+      return {
+        invalidateDataBuckets: true,
+        updatedDataBuckets: [],
+        invalidateParameterBuckets: false,
+        updatedParameterBucketDefinitions: []
+      };
+    }
     const key = `${options.lastCheckpoint}_${options.nextCheckpoint}`;
     const result = await this.checkpointChangesCache.fetch(key, { context: { options } });
     return result!;

packages/sync-rules/src/SqlBucketDescriptor.ts

@@ -133,6 +133,10 @@ export class SqlBucketDescriptor {
     return results;
   }
 
+  hasDynamicBucketQueries(): boolean {
+    return this.parameter_queries.length > 0;
+  }
+
   getSourceTables(): Set<TablePattern> {
     let result = new Set<TablePattern>();
     for (let query of this.parameter_queries) {

packages/sync-rules/src/SqlSyncRules.ts

@@ -326,6 +326,10 @@ export class SqlSyncRules implements SyncRules {
     return mergeBucketParameterQueriers(queriers);
   }
 
+  hasDynamicBucketQueries() {
+    return this.bucket_descriptors.some((query) => query.hasDynamicBucketQueries());
+  }
+
   getSourceTables(): TablePattern[] {
     const sourceTables = new Map<String, TablePattern>();
     for (const bucket of this.bucket_descriptors) {

packages/sync-rules/test/src/sync_rules.test.ts

@@ -37,6 +37,7 @@ bucket_definitions:
         bucket: 'mybucket[]'
       }
     ]);
+    expect(rules.hasDynamicBucketQueries).toBe(false);
     expect(rules.getBucketParameterQuerier(normalizeTokenParameters({}))).toMatchObject({
       staticBuckets: [{ bucket: 'mybucket[]', priority: 3 }],
       hasDynamicBuckets: false,
@@ -936,6 +937,7 @@ bucket_definitions:
     );
     const bucket = rules.bucket_descriptors[0];
     expect(bucket.bucket_parameters).toEqual(['user_id']);
+    expect(rules.hasDynamicBucketQueries).toBe(true);
 
     expect(rules.getBucketParameterQuerier(normalizeTokenParameters({ user_id: 'user1' }))).toMatchObject({
       hasDynamicBuckets: true,