Always expose sequential fluxes to account crawlers

service/src/main/java/org/whispersystems/textsecuregcm/storage/Accounts.java

@@ -45,7 +45,6 @@ import org.whispersystems.textsecuregcm.util.SystemMapper;
 import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.textsecuregcm.util.Util;
 import reactor.core.publisher.Flux;
-import reactor.core.publisher.ParallelFlux;
 import reactor.core.scheduler.Scheduler;
 import software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient;
 import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
@@ -1058,7 +1057,7 @@ public class Accounts extends AbstractDynamoDbStore {
             .thenRun(() -> sample.stop(DELETE_TIMER));
   }
 
-  ParallelFlux<Account> getAll(final int segments, final Scheduler scheduler) {
+  Flux<Account> getAll(final int segments, final Scheduler scheduler) {
     if (segments < 1) {
       throw new IllegalArgumentException("Total number of segments must be positive");
     }
@@ -1073,7 +1072,8 @@ public class Accounts extends AbstractDynamoDbStore {
                 .totalSegments(segments)
                 .build())
             .items()
-            .map(Accounts::fromItem));
+            .map(Accounts::fromItem))
+        .sequential();
   }
 
   @Nonnull

service/src/main/java/org/whispersystems/textsecuregcm/storage/AccountsManager.java

@@ -69,7 +69,7 @@ import org.whispersystems.textsecuregcm.util.ExceptionUtils;
 import org.whispersystems.textsecuregcm.util.Pair;
 import org.whispersystems.textsecuregcm.util.SystemMapper;
 import org.whispersystems.textsecuregcm.util.Util;
-import reactor.core.publisher.ParallelFlux;
+import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Scheduler;
 import software.amazon.awssdk.services.dynamodb.model.TransactWriteItem;
 
@@ -940,7 +940,7 @@ public class AccountsManager {
     return accounts.findRecentlyDeletedE164(uuid);
   }
 
-  public ParallelFlux<Account> streamAllFromDynamo(final int segments, final Scheduler scheduler) {
+  public Flux<Account> streamAllFromDynamo(final int segments, final Scheduler scheduler) {
     return accounts.getAll(segments, scheduler);
   }
 

service/src/main/java/org/whispersystems/textsecuregcm/workers/AbstractSinglePassCrawlAccountsCommand.java

@@ -18,7 +18,7 @@ import org.whispersystems.textsecuregcm.WhisperServerConfiguration;
 import org.whispersystems.textsecuregcm.metrics.MetricsUtil;
 import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.util.logging.UncaughtExceptionHandler;
-import reactor.core.publisher.ParallelFlux;
+import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Schedulers;
 
 public abstract class AbstractSinglePassCrawlAccountsCommand extends EnvironmentCommand<WhisperServerConfiguration> {
@@ -103,5 +103,5 @@ public abstract class AbstractSinglePassCrawlAccountsCommand extends Environment
     logger.error("Unhandled error", throwable);
   }
 
-  protected abstract void crawlAccounts(final ParallelFlux<Account> accounts);
+  protected abstract void crawlAccounts(final Flux<Account> accounts);
 }

service/src/main/java/org/whispersystems/textsecuregcm/workers/MigrateSignedECPreKeysCommand.java

@@ -22,7 +22,6 @@ import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.KeysManager;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
-import reactor.core.publisher.ParallelFlux;
 import reactor.util.function.Tuple3;
 import reactor.util.function.Tuples;
 import reactor.util.retry.Retry;
@@ -63,13 +62,12 @@ public class MigrateSignedECPreKeysCommand extends AbstractSinglePassCrawlAccoun
   }
 
   @Override
-  protected void crawlAccounts(final ParallelFlux<Account> accounts) {
+  protected void crawlAccounts(final Flux<Account> accounts) {
     final KeysManager keysManager = getCommandDependencies().keysManager();
     final int maxConcurrency = getNamespace().getInt(MAX_CONCURRENCY_ARGUMENT);
     final int bufferSize = getNamespace().getInt(BUFFER_ARGUMENT);
 
     accounts
-        .sequential()
         .flatMap(account -> Flux.fromIterable(account.getDevices())
             .flatMap(device -> Flux.fromArray(IdentityType.values())
                 .filter(identityType -> device.getSignedPreKey(identityType) != null)

service/src/main/java/org/whispersystems/textsecuregcm/workers/ProcessPushNotificationFeedbackCommand.java

@@ -20,8 +20,8 @@ import org.whispersystems.textsecuregcm.metrics.MetricsUtil;
 import org.whispersystems.textsecuregcm.metrics.UserAgentTagUtil;
 import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.Device;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
-import reactor.core.publisher.ParallelFlux;
 
 public class ProcessPushNotificationFeedbackCommand extends AbstractSinglePassCrawlAccountsCommand {
 
@@ -62,12 +62,11 @@ public class ProcessPushNotificationFeedbackCommand extends AbstractSinglePassCr
   }
 
   @Override
-  protected void crawlAccounts(final ParallelFlux<Account> accounts) {
+  protected void crawlAccounts(final Flux<Account> accounts) {
     final boolean isDryRun = getNamespace().getBoolean(DRY_RUN_ARGUMENT);
 
     accounts
         .filter(account -> account.getDevices().stream().anyMatch(this::deviceNeedsUpdate))
-        .sequential()
         .flatMap(account -> {
           account.getDevices().stream()
               .filter(this::deviceNeedsUpdate)

service/src/main/java/org/whispersystems/textsecuregcm/workers/RemoveExpiredAccountsCommand.java

@@ -19,7 +19,7 @@ import org.slf4j.LoggerFactory;
 import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.AccountsManager;
 import reactor.core.publisher.Mono;
-import reactor.core.publisher.ParallelFlux;
+import reactor.core.publisher.Flux;
 
 public class RemoveExpiredAccountsCommand extends AbstractSinglePassCrawlAccountsCommand {
 
@@ -57,13 +57,12 @@ public class RemoveExpiredAccountsCommand extends AbstractSinglePassCrawlAccount
   }
 
   @Override
-  protected void crawlAccounts(final ParallelFlux<Account> accounts) {
+  protected void crawlAccounts(final Flux<Account> accounts) {
     final boolean isDryRun = getNamespace().getBoolean(DRY_RUN_ARGUMENT);
     final Counter deletedAccountCounter =
         Metrics.counter(DELETED_ACCOUNT_COUNTER_NAME, "dryRun", String.valueOf(isDryRun));
 
     accounts.filter(this::isExpired)
-        .sequential()
         .flatMap(expiredAccount -> {
           final Mono<Void> deleteAccountMono = isDryRun
               ? Mono.empty()

service/src/test/java/org/whispersystems/textsecuregcm/storage/AccountsTest.java

@@ -665,7 +665,7 @@ class AccountsTest {
     }
 
     final List<Account> retrievedAccounts =
-        accounts.getAll(2, Schedulers.parallel()).sequential().collectList().block();
+        accounts.getAll(2, Schedulers.parallel()).collectList().block();
 
     assertNotNull(retrievedAccounts);
     assertEquals(expectedAccounts.stream().map(Account::getUuid).collect(Collectors.toSet()),

service/src/test/java/org/whispersystems/textsecuregcm/workers/ProcessPushNotificationFeedbackCommandTest.java

@@ -124,8 +124,7 @@ class ProcessPushNotificationFeedbackCommandTest {
     }
 
     processPushNotificationFeedbackCommand.crawlAccounts(
-        Flux.just(accountWithActiveDevice, accountWithUninstalledDevice, accountWithAlreadyDisabledUninstalledDevice)
+        Flux.just(accountWithActiveDevice, accountWithUninstalledDevice, accountWithAlreadyDisabledUninstalledDevice));
-            .parallel());
 
     if (isDryRun) {
       verify(accountsManager, never()).updateAsync(any(), any());

service/src/test/java/org/whispersystems/textsecuregcm/workers/RemoveExpiredAccountsCommandTest.java

@@ -73,7 +73,7 @@ class RemoveExpiredAccountsCommandTest {
     when(expiredAccount.getLastSeen())
         .thenReturn(clock.instant().minus(RemoveExpiredAccountsCommand.MAX_IDLE_DURATION).minusMillis(1).toEpochMilli());
 
-    removeExpiredAccountsCommand.crawlAccounts(Flux.just(activeAccount, expiredAccount).parallel());
+    removeExpiredAccountsCommand.crawlAccounts(Flux.just(activeAccount, expiredAccount));
 
     if (isDryRun) {
       verify(accountsManager, never()).delete(any(), any());