diff --git a/keyserver/src/creators/thread-creator.js b/keyserver/src/creators/thread-creator.js
index d79bc788d..479a73671 100644
--- a/keyserver/src/creators/thread-creator.js
+++ b/keyserver/src/creators/thread-creator.js
@@ -1,509 +1,523 @@
 // @flow
 
 import invariant from 'invariant';
 
 import bots from 'lib/facts/bots.js';
 import genesis from 'lib/facts/genesis.js';
 import { getRolePermissionBlobs } from 'lib/permissions/thread-permissions.js';
 import {
   generatePendingThreadColor,
   generateRandomColor,
 } from 'lib/shared/color-utils.js';
 import { isInvalidSidebarSource } from 'lib/shared/message-utils.js';
 import { getThreadTypeParentRequirement } from 'lib/shared/thread-utils.js';
 import { messageTypes } from 'lib/types/message-types-enum.js';
 import type { RawMessageInfo, MessageData } from 'lib/types/message-types.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import {
   threadTypes,
   threadTypeIsCommunityRoot,
 } from 'lib/types/thread-types-enum.js';
 import {
   type ServerNewThreadRequest,
   type NewThreadResponse,
 } from 'lib/types/thread-types.js';
 import type { ServerUpdateInfo } from 'lib/types/update-types.js';
 import type { UserInfos } from 'lib/types/user-types.js';
 import { pushAll } from 'lib/utils/array.js';
 import { ServerError } from 'lib/utils/errors.js';
 import { promiseAll } from 'lib/utils/promises.js';
 import { firstLine } from 'lib/utils/string-utils.js';
 
 import createIDs from './id-creator.js';
 import createMessages from './message-creator.js';
 import { createInitialRolesForNewThread } from './role-creator.js';
 import type { UpdatesForCurrentSession } from './update-creator.js';
 import { dbQuery, SQL } from '../database/database.js';
 import {
   fetchLatestEditMessageContentByID,
   fetchMessageInfoByID,
 } from '../fetchers/message-fetchers.js';
 import {
   determineThreadAncestry,
   personalThreadQuery,
 } from '../fetchers/thread-fetchers.js';
 import {
   checkThreadPermission,
   validateCandidateMembers,
 } from '../fetchers/thread-permission-fetchers.js';
 import type { Viewer } from '../session/viewer.js';
 import {
   changeRole,
   recalculateThreadPermissions,
   commitMembershipChangeset,
   getChangesetCommitResultForExistingThread,
   type MembershipChangeset,
 } from '../updaters/thread-permission-updaters.js';
 import { joinThread } from '../updaters/thread-updaters.js';
 import RelationshipChangeset from '../utils/relationship-changeset.js';
 
 const { commbot } = bots;
 
 const privateThreadDescription: string =
   'This is your private chat, ' +
   'where you can set reminders and jot notes in private!';
 
 type CreateThreadOptions = Partial<{
   +forceAddMembers: boolean,
   +updatesForCurrentSession: UpdatesForCurrentSession,
   +silentlyFailMembers: boolean,
 }>;
 
 // If forceAddMembers is set, we will allow the viewer to add random users who
 // they aren't friends with. We will only fail if the viewer is trying to add
 // somebody who they have blocked or has blocked them. On the other hand, if
 // forceAddMembers is not set, we will fail if the viewer tries to add somebody
 // who they aren't friends with and doesn't have a membership row with a
 // nonnegative role for the parent thread.
 async function createThread(
   viewer: Viewer,
   request: ServerNewThreadRequest,
   options?: CreateThreadOptions,
 ): Promise<NewThreadResponse> {
   if (!viewer.loggedIn) {
     throw new ServerError('not_logged_in');
   }
 
   const forceAddMembers = options?.forceAddMembers ?? false;
   const updatesForCurrentSession =
     options?.updatesForCurrentSession ?? 'return';
   const silentlyFailMembers = options?.silentlyFailMembers ?? false;
 
   const threadType = request.type;
   const shouldCreateRelationships =
     forceAddMembers || threadType === threadTypes.PERSONAL;
   let parentThreadID = request.parentThreadID ? request.parentThreadID : null;
   const initialMemberIDsFromRequest =
     request.initialMemberIDs && request.initialMemberIDs.length > 0
       ? [...new Set(request.initialMemberIDs)]
       : null;
   const ghostMemberIDsFromRequest =
     request.ghostMemberIDs && request.ghostMemberIDs.length > 0
       ? [...new Set(request.ghostMemberIDs)]
       : null;
 
   const sourceMessageID = request.sourceMessageID
     ? request.sourceMessageID
     : null;
   invariant(
     threadType !== threadTypes.SIDEBAR || sourceMessageID,
     'sourceMessageID should be set for sidebar',
   );
 
   const parentRequirement = getThreadTypeParentRequirement(threadType);
   if (
     (parentRequirement === 'required' && !parentThreadID) ||
     (parentRequirement === 'disabled' && parentThreadID)
   ) {
     throw new ServerError('invalid_parameters');
   }
 
   if (
     threadType === threadTypes.PERSONAL &&
     request.initialMemberIDs?.length !== 1
   ) {
     throw new ServerError('invalid_parameters');
   }
 
   const requestParentThreadID = parentThreadID;
   const confirmParentPermissionPromise = (async () => {
     if (!requestParentThreadID) {
       return;
     }
     const hasParentPermission = await checkThreadPermission(
       viewer,
       requestParentThreadID,
       threadType === threadTypes.SIDEBAR
         ? threadPermissions.CREATE_SIDEBARS
         : threadPermissions.CREATE_SUBCHANNELS,
     );
     if (!hasParentPermission) {
       throw new ServerError('invalid_credentials');
     }
   })();
 
   // This is a temporary hack until we release actual E2E-encrypted local
   // conversations. For now we are hosting all root threads on Ashoat's
   // keyserver, so we set them to the have the Genesis community as their
   // parent thread.
   if (!parentThreadID && !threadTypeIsCommunityRoot(threadType)) {
     parentThreadID = genesis().id;
   }
 
   const determineThreadAncestryPromise = determineThreadAncestry(
     parentThreadID,
     threadType,
   );
 
   const validateMembersPromise = (async () => {
     const threadAncestry = await determineThreadAncestryPromise;
     const defaultRolePermissions = getRolePermissionBlobs(threadType).Members;
     const { initialMemberIDs, ghostMemberIDs } = await validateCandidateMembers(
       viewer,
       {
         initialMemberIDs: initialMemberIDsFromRequest,
         ghostMemberIDs: ghostMemberIDsFromRequest,
       },
       {
         threadType,
         parentThreadID,
         containingThreadID: threadAncestry.containingThreadID,
         defaultRolePermissions,
       },
       { requireRelationship: !shouldCreateRelationships },
     );
     if (
       !silentlyFailMembers &&
       (Number(initialMemberIDs?.length) <
         Number(initialMemberIDsFromRequest?.length) ||
         Number(ghostMemberIDs?.length) <
           Number(ghostMemberIDsFromRequest?.length))
     ) {
       throw new ServerError('invalid_credentials');
     }
     return { initialMemberIDs, ghostMemberIDs };
   })();
 
   const sourceMessagePromise: Promise<?RawMessageInfo> = sourceMessageID
     ? fetchMessageInfoByID(viewer, sourceMessageID)
     : Promise.resolve(undefined);
   const {
     sourceMessage,
     threadAncestry,
     validateMembers: { initialMemberIDs, ghostMemberIDs },
   } = await promiseAll({
     sourceMessage: sourceMessagePromise,
     threadAncestry: determineThreadAncestryPromise,
     validateMembers: validateMembersPromise,
     confirmParentPermission: confirmParentPermissionPromise,
   });
 
   if (sourceMessage && isInvalidSidebarSource(sourceMessage)) {
     throw new ServerError('invalid_parameters');
   }
 
   let { id } = request;
   if (id === null || id === undefined) {
     const ids = await createIDs('threads', 1);
     id = ids[0];
   }
   const newRoles = await createInitialRolesForNewThread(id, threadType);
 
   const name = request.name ? firstLine(request.name) : null;
   const description = request.description ? request.description : null;
   let color = request.color
     ? request.color.toLowerCase()
     : generateRandomColor();
   if (threadType === threadTypes.PERSONAL) {
     color = generatePendingThreadColor([
       ...(request.initialMemberIDs ?? []),
       viewer.id,
     ]);
   }
 
   const time = Date.now();
 
   const row = [
     id,
     threadType,
     name,
     description,
     viewer.userID,
     time,
     color,
     parentThreadID,
     threadAncestry.containingThreadID,
     threadAncestry.community,
     threadAncestry.depth,
     sourceMessageID,
   ];
 
   let existingThreadQuery = null;
   if (threadType === threadTypes.PERSONAL) {
     const otherMemberID = initialMemberIDs?.[0];
     invariant(
       otherMemberID,
       'Other member id should be set for a PERSONAL thread',
     );
     existingThreadQuery = personalThreadQuery(viewer.userID, otherMemberID);
   } else if (sourceMessageID) {
     existingThreadQuery = SQL`
       SELECT t.id
       FROM threads t
       WHERE t.source_message = ${sourceMessageID}
     `;
   }
 
   if (existingThreadQuery) {
     const query = SQL`
       INSERT INTO threads(id, type, name, description, creator, creation_time,
         color, parent_thread_id, containing_thread_id, community, depth,
         source_message)
       SELECT ${row}
       WHERE NOT EXISTS (`;
     query.append(existingThreadQuery).append(SQL`)`);
     const [result] = await dbQuery(query);
 
     if (result.affectedRows === 0) {
       const deleteRoles = SQL`
         DELETE FROM roles
         WHERE id IN (${newRoles.default.id}, ${newRoles.creator.id})
       `;
       const deleteIDs = SQL`
         DELETE FROM ids
         WHERE id IN (${id}, ${newRoles.default.id}, ${newRoles.creator.id})
       `;
       const [[existingThreadResult]] = await Promise.all([
         dbQuery(existingThreadQuery),
         dbQuery(deleteRoles),
         dbQuery(deleteIDs),
       ]);
       invariant(existingThreadResult.length > 0, 'thread should exist');
       const existingThreadID = existingThreadResult[0].id.toString();
 
       invariant(request.calendarQuery, 'calendar query should exist');
       const calendarQuery = {
         ...request.calendarQuery,
         filters: [
           ...request.calendarQuery.filters,
           { type: 'threads', threadIDs: [existingThreadID] },
         ],
       };
 
       let joinUpdateInfos: $ReadOnlyArray<ServerUpdateInfo> = [];
       let userInfos: UserInfos = {};
       let newMessageInfos: $ReadOnlyArray<RawMessageInfo> = [];
       if (threadType !== threadTypes.PERSONAL) {
         const joinThreadResult = await joinThread(viewer, {
           threadID: existingThreadID,
           calendarQuery,
         });
         joinUpdateInfos = joinThreadResult.updatesResult.newUpdates;
         userInfos = joinThreadResult.userInfos;
         newMessageInfos = joinThreadResult.rawMessageInfos;
       }
 
       const { viewerUpdates: newUpdates, userInfos: changesetUserInfos } =
         await getChangesetCommitResultForExistingThread(
           viewer,
           existingThreadID,
           joinUpdateInfos,
           { calendarQuery, updatesForCurrentSession },
         );
       userInfos = { ...userInfos, ...changesetUserInfos };
 
       return {
         newThreadID: existingThreadID,
         updatesResult: {
           newUpdates,
         },
         userInfos,
         newMessageInfos,
       };
     }
   } else {
     const query = SQL`
+      START TRANSACTION;
+
       INSERT INTO threads(id, type, name, description, creator, creation_time,
         color, parent_thread_id, containing_thread_id, community, depth,
         source_message)
-      VALUES ${[row]}
+      VALUES ${[row]};
     `;
-    await dbQuery(query);
+
+    if (threadTypeIsCommunityRoot(threadType)) {
+      query.append(SQL`
+        INSERT INTO communities (id)
+        VALUES (${id});
+      `);
+    }
+
+    query.append(SQL`
+      COMMIT;
+    `);
+
+    await dbQuery(query, { multipleStatements: true });
   }
 
   const initialMemberPromise: Promise<?MembershipChangeset> = initialMemberIDs
     ? changeRole(id, initialMemberIDs, null, { setNewMembersToUnread: true })
     : Promise.resolve(undefined);
   const ghostMemberPromise: Promise<?MembershipChangeset> = ghostMemberIDs
     ? changeRole(id, ghostMemberIDs, -1)
     : Promise.resolve(undefined);
 
   const [
     creatorChangeset,
     initialMembersChangeset,
     ghostMembersChangeset,
     recalculatePermissionsChangeset,
   ] = await Promise.all([
     changeRole(id, [viewer.userID], newRoles.creator.id),
     initialMemberPromise,
     ghostMemberPromise,
     recalculateThreadPermissions(id),
   ]);
 
   const {
     membershipRows: creatorMembershipRows,
     relationshipChangeset: creatorRelationshipChangeset,
   } = creatorChangeset;
 
   const {
     membershipRows: recalculateMembershipRows,
     relationshipChangeset: recalculateRelationshipChangeset,
   } = recalculatePermissionsChangeset;
 
   const membershipRows = [
     ...creatorMembershipRows,
     ...recalculateMembershipRows,
   ];
   const relationshipChangeset = new RelationshipChangeset();
   relationshipChangeset.addAll(creatorRelationshipChangeset);
   relationshipChangeset.addAll(recalculateRelationshipChangeset);
 
   if (initialMembersChangeset) {
     const {
       membershipRows: initialMembersMembershipRows,
       relationshipChangeset: initialMembersRelationshipChangeset,
     } = initialMembersChangeset;
     pushAll(membershipRows, initialMembersMembershipRows);
     relationshipChangeset.addAll(initialMembersRelationshipChangeset);
   }
   if (ghostMembersChangeset) {
     const {
       membershipRows: ghostMembersMembershipRows,
       relationshipChangeset: ghostMembersRelationshipChangeset,
     } = ghostMembersChangeset;
     pushAll(membershipRows, ghostMembersMembershipRows);
     relationshipChangeset.addAll(ghostMembersRelationshipChangeset);
   }
 
   const changeset = { membershipRows, relationshipChangeset };
   const { viewerUpdates, userInfos } = await commitMembershipChangeset(
     viewer,
     changeset,
     {
       updatesForCurrentSession,
     },
   );
 
   const initialMemberAndCreatorIDs = initialMemberIDs
     ? [...initialMemberIDs, viewer.userID]
     : [viewer.userID];
   const messageDatas: Array<MessageData> = [];
   if (threadType !== threadTypes.SIDEBAR) {
     messageDatas.push({
       type: messageTypes.CREATE_THREAD,
       threadID: id,
       creatorID: viewer.userID,
       time,
       initialThreadState: {
         type: threadType,
         name,
         parentThreadID,
         color,
         memberIDs: initialMemberAndCreatorIDs,
       },
     });
   } else {
     invariant(parentThreadID, 'parentThreadID should be set for sidebar');
     if (!sourceMessage) {
       throw new ServerError('invalid_parameters');
     }
     invariant(
       sourceMessage.type !== messageTypes.REACTION &&
         sourceMessage.type !== messageTypes.EDIT_MESSAGE &&
         sourceMessage.type !== messageTypes.SIDEBAR_SOURCE &&
         sourceMessage.type !== messageTypes.TOGGLE_PIN,
       'Invalid sidebar source type',
     );
 
     let editedSourceMessage = sourceMessage;
     if (sourceMessageID && sourceMessage.type === messageTypes.TEXT) {
       const editMessageContent =
         await fetchLatestEditMessageContentByID(sourceMessageID);
       if (editMessageContent) {
         editedSourceMessage = {
           ...sourceMessage,
           text: editMessageContent.text,
         };
       }
     }
 
     messageDatas.push(
       {
         type: messageTypes.SIDEBAR_SOURCE,
         threadID: id,
         creatorID: viewer.userID,
         time,
         sourceMessage: editedSourceMessage,
       },
       {
         type: messageTypes.CREATE_SIDEBAR,
         threadID: id,
         creatorID: viewer.userID,
         time,
         sourceMessageAuthorID: sourceMessage.creatorID,
         initialThreadState: {
           name,
           parentThreadID,
           color,
           memberIDs: initialMemberAndCreatorIDs,
         },
       },
     );
   }
 
   if (
     parentThreadID &&
     threadType !== threadTypes.SIDEBAR &&
     (parentThreadID !== genesis().id ||
       threadType === threadTypes.COMMUNITY_OPEN_SUBTHREAD ||
       threadType === threadTypes.COMMUNITY_OPEN_ANNOUNCEMENT_SUBTHREAD)
   ) {
     messageDatas.push({
       type: messageTypes.CREATE_SUB_THREAD,
       threadID: parentThreadID,
       creatorID: viewer.userID,
       time,
       childThreadID: id,
     });
   }
   const newMessageInfos = await createMessages(
     viewer,
     messageDatas,
     updatesForCurrentSession,
   );
 
   return {
     newThreadID: id,
     updatesResult: {
       newUpdates: viewerUpdates,
     },
     userInfos,
     newMessageInfos,
   };
 }
 
 function createPrivateThread(viewer: Viewer): Promise<NewThreadResponse> {
   return createThread(
     viewer,
     {
       type: threadTypes.PRIVATE,
       description: privateThreadDescription,
       ghostMemberIDs: [commbot.userID],
     },
     {
       forceAddMembers: true,
     },
   );
 }
 
 export { createThread, createPrivateThread, privateThreadDescription };
diff --git a/keyserver/src/deleters/thread-deleters.js b/keyserver/src/deleters/thread-deleters.js
index efe73d9d7..d1e8db619 100644
--- a/keyserver/src/deleters/thread-deleters.js
+++ b/keyserver/src/deleters/thread-deleters.js
@@ -1,149 +1,150 @@
 // @flow
 
 import { permissionLookup } from 'lib/permissions/thread-permissions.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import {
   type ThreadDeletionRequest,
   type LeaveThreadResult,
 } from 'lib/types/thread-types.js';
 import { updateTypes } from 'lib/types/update-types-enum.js';
 import { ServerError } from 'lib/utils/errors.js';
 
 import { createUpdates } from '../creators/update-creator.js';
 import { dbQuery, SQL } from '../database/database.js';
 import {
   fetchServerThreadInfos,
   fetchContainedThreadIDs,
 } from '../fetchers/thread-fetchers.js';
 import { fetchThreadPermissionsBlob } from '../fetchers/thread-permission-fetchers.js';
 import { fetchUpdateInfoForThreadDeletion } from '../fetchers/update-fetchers.js';
 import { rescindPushNotifs } from '../push/rescind.js';
 import type { Viewer } from '../session/viewer.js';
 
 type DeleteThreadOptions = Partial<{
   +ignorePermissions: boolean,
 }>;
 async function deleteThread(
   viewer: Viewer,
   threadDeletionRequest: ThreadDeletionRequest,
   options?: DeleteThreadOptions,
 ): Promise<LeaveThreadResult> {
   if (!viewer.loggedIn) {
     throw new ServerError('not_logged_in');
   }
   const ignorePermissions =
     (options?.ignorePermissions && viewer.isScriptViewer) ?? false;
 
   const { threadID } = threadDeletionRequest;
 
   const permissionsBlob = await fetchThreadPermissionsBlob(viewer, threadID);
 
   if (!permissionsBlob && !ignorePermissions) {
     // This should only occur if the first request goes through but the client
     // never receives the response
     const { updateInfos } = await fetchUpdateInfoForThreadDeletion(
       viewer,
       threadID,
     );
     return { updatesResult: { newUpdates: updateInfos } };
   }
 
   const hasPermission = permissionLookup(
     permissionsBlob,
     threadPermissions.DELETE_THREAD,
   );
   if (!hasPermission && !ignorePermissions) {
     throw new ServerError('invalid_credentials');
   }
 
   // TODO: handle descendant thread permission update correctly.
   //       thread-permission-updaters should be used for descendant threads.
   const threadIDs = await fetchContainedThreadIDs(threadID);
 
   const [{ threadInfos: serverThreadInfos }] = await Promise.all([
     fetchServerThreadInfos({ threadIDs: new Set(threadIDs) }),
     rescindPushNotifs(
       SQL`n.thread IN (${threadIDs})`,
       SQL`IF(m.thread IN (${threadIDs}), NULL, m.thread)`,
     ),
   ]);
 
   const time = Date.now();
   const updateDatas = [];
   for (const containedThreadID of threadIDs) {
     for (const memberInfo of serverThreadInfos[containedThreadID].members) {
       updateDatas.push({
         type: updateTypes.DELETE_THREAD,
         userID: memberInfo.id,
         time,
         threadID: containedThreadID,
       });
     }
   }
 
   const [{ viewerUpdates }] = await Promise.all([
     createUpdates(updateDatas, { viewer, updatesForCurrentSession: 'return' }),
     deleteThreadsFromDB(threadIDs),
   ]);
 
   return { updatesResult: { newUpdates: viewerUpdates } };
 }
 
 function deleteThreadsFromDB(
   threadIDs: $ReadOnlyArray<string>,
 ): Promise<mixed> {
   const deletionQuery = SQL`
     START TRANSACTION;
     DELETE FROM threads WHERE id IN (${threadIDs});
+    DELETE FROM communities WHERE id IN (${threadIDs});
     DELETE FROM ids WHERE id IN (${threadIDs});
     DELETE d, id, e, ie, r, ir
       FROM days d
       LEFT JOIN ids id ON id.id = d.id
       LEFT JOIN entries e ON e.day = d.id
       LEFT JOIN ids ie ON ie.id = e.id
       LEFT JOIN revisions r ON r.entry = e.id
       LEFT JOIN ids ir ON ir.id = r.id
       WHERE d.thread IN (${threadIDs});
     DELETE FROM memberships WHERE thread IN (${threadIDs});
     DELETE r, i
       FROM roles r
       LEFT JOIN ids i ON i.id = r.id
       WHERE r.thread IN (${threadIDs});
     DELETE m, im, u, iu
       FROM messages m
       LEFT JOIN ids im ON im.id = m.id
       LEFT JOIN uploads u ON u.container = m.id
       LEFT JOIN ids iu ON iu.id = u.id
       WHERE m.thread IN (${threadIDs});
     DELETE FROM uploads WHERE container IN (${threadIDs});
     DELETE FROM focused WHERE thread IN (${threadIDs});
     DELETE n, i
       FROM notifications n
       LEFT JOIN ids i ON i.id = n.id
       WHERE n.thread IN (${threadIDs});
     COMMIT;
   `;
   return dbQuery(deletionQuery, { multipleStatements: true });
 }
 
 async function deleteInaccessibleThreads(): Promise<void> {
   // A thread is considered "inaccessible" if it has no membership rows. Note
   // that membership rows exist whenever a user can see a thread, even if they
   // are not technically a member (in which case role=0). For now, we're also
   // excluding threads with children, since to properly delete those we would
   // need to update their parent_thread_id, and possibly change their type.
   const [fetchResult] = await dbQuery(SQL`
     SELECT t.id
     FROM threads t
     LEFT JOIN memberships m ON m.thread = t.id AND m.role > -1
     LEFT JOIN threads c ON c.parent_thread_id = t.id
     WHERE m.thread IS NULL AND c.id IS NULL
   `);
   const threadIDs = new Set(fetchResult.map(({ id }) => id));
   if (threadIDs.size === 0) {
     return;
   }
   await deleteThreadsFromDB([...threadIDs]);
 }
 
 export { deleteThread, deleteInaccessibleThreads };