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Fix missing query results when it is a match after a local patch mutation. #1957

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Jul 12, 2019
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77 changes: 59 additions & 18 deletions packages/firestore/src/local/local_documents_view.ts
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ import { Query } from '../core/query';
import { SnapshotVersion } from '../core/snapshot_version';
import {
DocumentKeySet,
documentKeySet,
DocumentMap,
documentMap,
MaybeDocumentMap,
Expand All @@ -34,6 +35,7 @@ import { ResourcePath } from '../model/path';
import { assert } from '../util/assert';
import { IndexManager } from './index_manager';
import { MutationQueue } from './mutation_queue';
import { PatchMutation } from '../model/mutation';
import { PersistenceTransaction } from './persistence';
import { PersistencePromise } from './persistence_promise';
import { RemoteDocumentCache } from './remote_document_cache';
Expand All @@ -49,7 +51,7 @@ export class LocalDocumentsView {
private remoteDocumentCache: RemoteDocumentCache,
private mutationQueue: MutationQueue,
private indexManager: IndexManager
) {}
) { }

/**
* Get the local view of the document identified by `key`.
Expand Down Expand Up @@ -208,6 +210,7 @@ export class LocalDocumentsView {
): PersistencePromise<DocumentMap> {
// Query the remote documents and overlay mutations.
let results: DocumentMap;
let mutationBatches: MutationBatch[];
return this.remoteDocumentCache
.getDocumentsMatchingQuery(transaction, query)
.next(queryResults => {
Expand All @@ -218,27 +221,41 @@ export class LocalDocumentsView {
);
})
.next(matchingMutationBatches => {
for (const batch of matchingMutationBatches) {
for (const mutation of batch.mutations) {
const key = mutation.key;
// Only process documents belonging to the collection.
if (!query.path.isImmediateParentOf(key.path)) {
continue;
mutationBatches = matchingMutationBatches;
// It is possible that a PatchMutation can make a document match a query, even if
// the version in the RemoteDocumentCache is not a match yet (waiting for server
// to ack). To handle this, we find all document keys affected by the PatchMutations
// that are not in `result` yet, and back fill them via `remoteDocumentCache.getEntries`,
// otherwise those `PatchMutations` will be ignored because no base document can be found,
// and lead to missing result for the query.
return this.getMissingBaseDocuments(
transaction,
mutationBatches,
results
).next(missingBaseDocuments => {
missingBaseDocuments.forEach((key, doc) => {
if (doc !== null && doc instanceof Document) {
results = results.insert(key, doc);
}
});

const baseDoc = results.get(key);
const mutatedDoc = mutation.applyToLocalView(
baseDoc,
baseDoc,
batch.localWriteTime
);
if (mutatedDoc instanceof Document) {
results = results.insert(key, mutatedDoc);
} else {
results = results.remove(key);
for (const batch of mutationBatches) {
for (const mutation of batch.mutations) {
const key = mutation.key;
const baseDoc = results.get(key);
const mutatedDoc = mutation.applyToLocalView(
baseDoc,
baseDoc,
batch.localWriteTime
);
if (mutatedDoc instanceof Document) {
results = results.insert(key, mutatedDoc);
} else {
results = results.remove(key);
}
}
}
}
});
})
.next(() => {
// Finally, filter out any documents that don't actually match
Expand All @@ -252,4 +269,28 @@ export class LocalDocumentsView {
return results;
});
}

private getMissingBaseDocuments(
transaction: PersistenceTransaction,
matchingMutationBatches: MutationBatch[],
existingDocuments: DocumentMap
): PersistencePromise<NullableMaybeDocumentMap> {
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Would it make sense for this to return a DocumentMap? It would simplify the code above, but you would need to post-filter in here. Alternatively, you could also assemble the final result map here and make this a populateDocumentMapWithMissingBaseDocuments() or something similar. Optional.

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My understanding is DocumentMap being an immutable structure makes it awkward to update from the helper function. I have not tried it..but don't expect it to work without extra tricks.

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You can get return the combined set of existingDocuments and the result of this function. The goal would be to simplify the getDocumentsMatchingCollectionQuery function.

Optional.

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Decide not to do it because it is not a significant improvement..

let missingBaseDocEntriesForPatching = documentKeySet();
for (const batch of matchingMutationBatches) {
for (const mutation of batch.mutations) {
if (
mutation instanceof PatchMutation &&
existingDocuments.get(mutation.key) === null
) {
missingBaseDocEntriesForPatching = missingBaseDocEntriesForPatching.add(
mutation.key
);
}
}
}
return this.remoteDocumentCache.getEntries(
transaction,
missingBaseDocEntriesForPatching
);
}
}
39 changes: 38 additions & 1 deletion packages/firestore/test/unit/specs/query_spec.test.ts
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
*/

import { Query } from '../../../src/core/query';
import { doc, filter } from '../../util/helpers';
import { doc, filter, path } from '../../util/helpers';

import { Document } from '../../../src/model/document';
import { ResourcePath } from '../../../src/model/path';
Expand Down Expand Up @@ -98,4 +98,41 @@ describeSpec('Queries:', [], () => {
hasPendingWrites: true
});
});

specTest(
'Latency-compensated updates are included in query results',
[],
() => {
const fullQuery = Query.atPath(path('collection'));
const filteredQuery = fullQuery.addFilter(filter('match', '==', true));
const docA = doc('collection/a', 1000, { match: false });
const docAv2Local = doc(
'collection/a',
1000,
{ match: true },
{ hasLocalMutations: true }
);

return (
spec()
.userListens(fullQuery)
.watchAcksFull(fullQuery, 1000, docA)
.expectEvents(fullQuery, { added: [docA] })

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I believe that if you do userUnlisten(fullQuery) here then you can remove the event right below and further narrow down your test case.

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I'm not sure i understand..can you explain more?

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I am myself no longer fully sold on my idea. But let me explain what I had in mind:

    spec()
          .withGcEnabled(false)
          .userListens(fullQuery)
          .watchAcksFull(fullQuery, 1000, docA)
          .expectEvents(fullQuery, { added: [docA] })
          .userUnlistens(fullQuery)
          .userPatches('collection/a', { match: true })
          .userListens(filteredQuery)
          .expectEvents(filteredQuery, {
            added: [docAv2Local],
            fromCache: true,
            hasPendingWrites: true
          })

I believe this would work and it would remove the event in line 124 that is not directly related to your change. The reason I am no longer fully sold on this is that you would have to run the test with GC disabled to make this work. Otherwise, the SDK would delete docA from the RemoteDocumentCache as the user unlistens.

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Yep, can confirm what you described. Without GC disabled this is not working.

I am keep it as-is as that is slightly more likely what happens in real world.

// patch docA so that it will now match the filtered query.
.userPatches('collection/a', { match: true })
.expectEvents(fullQuery, {
modified: [docAv2Local],
hasPendingWrites: true
})
// Make sure docA shows up in filtered query.
.userListens(filteredQuery)
.expectEvents(filteredQuery, {
added: [docAv2Local],
fromCache: true,
hasPendingWrites: true
})
);
}
);
});