diff --git a/keyserver/src/fetchers/message-fetchers.js b/keyserver/src/fetchers/message-fetchers.js
index 022edff06..808d4c2ac 100644
--- a/keyserver/src/fetchers/message-fetchers.js
+++ b/keyserver/src/fetchers/message-fetchers.js
@@ -1,755 +1,727 @@
 // @flow
 
 import invariant from 'invariant';
 
 import {
   sortMessageInfoList,
   shimUnsupportedRawMessageInfos,
 } from 'lib/shared/message-utils';
 import { messageSpecs } from 'lib/shared/messages/message-specs';
 import { notifCollapseKeyForRawMessageInfo } from 'lib/shared/notif-utils';
 import { hasMinCodeVersion } from 'lib/shared/version-utils';
 import {
   type RawMessageInfo,
   type RawComposableMessageInfo,
   type RawRobotextMessageInfo,
   messageTypes,
   type MessageType,
   assertMessageType,
   type MessageSelectionCriteria,
   type MessageTruncationStatus,
   messageTruncationStatus,
   type FetchMessageInfosResult,
   defaultMaxMessageAge,
 } from 'lib/types/message-types';
 import { threadPermissions } from 'lib/types/thread-types';
 import { ServerError } from 'lib/utils/errors';
 
 import {
   dbQuery,
   SQL,
   mergeOrConditions,
   mergeAndConditions,
 } from '../database/database';
 import { getDBType } from '../database/db-config';
 import type { SQLStatementType } from '../database/types';
 import type { PushInfo } from '../push/send';
 import type { Viewer } from '../session/viewer';
 import { creationString, localIDFromCreationString } from '../utils/idempotent';
 import { mediaFromRow } from './upload-fetchers';
 
 export type CollapsableNotifInfo = {
   collapseKey: ?string,
   existingMessageInfos: RawMessageInfo[],
   newMessageInfos: RawMessageInfo[],
 };
 export type FetchCollapsableNotifsResult = {
   [userID: string]: CollapsableNotifInfo[],
 };
 
 const visibleExtractString = `$.${threadPermissions.VISIBLE}.value`;
 
 // This function doesn't filter RawMessageInfos based on what messageTypes the
 // client supports, since each user can have multiple clients. The caller must
 // handle this filtering.
 async function fetchCollapsableNotifs(
   pushInfo: PushInfo,
 ): Promise<FetchCollapsableNotifsResult> {
   // First, we need to fetch any notifications that should be collapsed
   const usersToCollapseKeysToInfo = {};
   const usersToCollapsableNotifInfo = {};
   for (const userID in pushInfo) {
     usersToCollapseKeysToInfo[userID] = {};
     usersToCollapsableNotifInfo[userID] = [];
     for (const rawMessageInfo of pushInfo[userID].messageInfos) {
       const collapseKey = notifCollapseKeyForRawMessageInfo(rawMessageInfo);
       if (!collapseKey) {
         const collapsableNotifInfo = {
           collapseKey,
           existingMessageInfos: [],
           newMessageInfos: [rawMessageInfo],
         };
         usersToCollapsableNotifInfo[userID].push(collapsableNotifInfo);
         continue;
       }
       if (!usersToCollapseKeysToInfo[userID][collapseKey]) {
         usersToCollapseKeysToInfo[userID][collapseKey] = {
           collapseKey,
           existingMessageInfos: [],
           newMessageInfos: [],
         };
       }
       usersToCollapseKeysToInfo[userID][collapseKey].newMessageInfos.push(
         rawMessageInfo,
       );
     }
   }
 
   const sqlTuples = [];
   for (const userID in usersToCollapseKeysToInfo) {
     const collapseKeysToInfo = usersToCollapseKeysToInfo[userID];
     for (const collapseKey in collapseKeysToInfo) {
       sqlTuples.push(
         SQL`(n.user = ${userID} AND n.collapse_key = ${collapseKey})`,
       );
     }
   }
 
   if (sqlTuples.length === 0) {
     return usersToCollapsableNotifInfo;
   }
 
   const collapseQuery = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type,
       m.user AS creatorID, stm.permissions AS subthread_permissions, n.user,
       n.collapse_key, up.id AS uploadID, up.type AS uploadType,
       up.secret AS uploadSecret, up.extra AS uploadExtra
     FROM notifications n
     LEFT JOIN messages m ON m.id = n.message
     LEFT JOIN uploads up ON up.container = m.id
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = n.user
     LEFT JOIN memberships stm
       ON m.type = ${messageTypes.CREATE_SUB_THREAD}
         AND stm.thread = m.content AND stm.user = n.user
     WHERE n.rescinded = 0 AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
   collapseQuery.append(mergeOrConditions(sqlTuples));
   collapseQuery.append(SQL`ORDER BY m.time DESC, m.id DESC`);
   const [collapseResult] = await dbQuery(collapseQuery);
 
   const rowsByUser = new Map();
   for (const row of collapseResult) {
     const user = row.user.toString();
     const currentRowsForUser = rowsByUser.get(user);
     if (currentRowsForUser) {
       currentRowsForUser.push(row);
     } else {
       rowsByUser.set(user, [row]);
     }
   }
 
   const derivedMessages = await fetchDerivedMessages(collapseResult);
 
   const parsePromises = [...rowsByUser.values()].map(userRows =>
     parseMessageSQLResult(userRows, derivedMessages),
   );
   const parsedMessages = await Promise.all(parsePromises);
 
   for (const messages of parsedMessages) {
     for (const message of messages) {
       const { rawMessageInfo, rows } = message;
       const [row] = rows;
       const info = usersToCollapseKeysToInfo[row.user][row.collapse_key];
       info.existingMessageInfos.push(rawMessageInfo);
     }
   }
 
   for (const userID in usersToCollapseKeysToInfo) {
     const collapseKeysToInfo = usersToCollapseKeysToInfo[userID];
     for (const collapseKey in collapseKeysToInfo) {
       const info = collapseKeysToInfo[collapseKey];
       usersToCollapsableNotifInfo[userID].push({
         collapseKey: info.collapseKey,
         existingMessageInfos: sortMessageInfoList(info.existingMessageInfos),
         newMessageInfos: sortMessageInfoList(info.newMessageInfos),
       });
     }
   }
 
   return usersToCollapsableNotifInfo;
 }
 
 type MessageSQLResult = $ReadOnlyArray<{
   rawMessageInfo: RawMessageInfo,
   rows: $ReadOnlyArray<Object>,
 }>;
 async function parseMessageSQLResult(
   rows: $ReadOnlyArray<Object>,
   derivedMessages: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
   viewer?: Viewer,
 ): Promise<MessageSQLResult> {
   const rowsByID = new Map();
   for (const row of rows) {
     const id = row.id.toString();
     const currentRowsForID = rowsByID.get(id);
     if (currentRowsForID) {
       currentRowsForID.push(row);
     } else {
       rowsByID.set(id, [row]);
     }
   }
 
   const messagePromises = [...rowsByID.values()].map(async messageRows => {
     const rawMessageInfo = await rawMessageInfoFromRows(
       messageRows,
       viewer,
       derivedMessages,
     );
     return rawMessageInfo ? { rawMessageInfo, rows: messageRows } : null;
   });
   const messages = await Promise.all(messagePromises);
   return messages.filter(Boolean);
 }
 
 function assertSingleRow(rows: $ReadOnlyArray<Object>): Object {
   if (rows.length === 0) {
     throw new Error('expected single row, but none present!');
   } else if (rows.length !== 1) {
     const messageIDs = rows.map(row => row.id.toString());
     console.warn(
       `expected single row, but there are multiple! ${messageIDs.join(', ')}`,
     );
   }
   return rows[0];
 }
 
 function mostRecentRowType(rows: $ReadOnlyArray<Object>): MessageType {
   if (rows.length === 0) {
     throw new Error('expected row, but none present!');
   }
   return assertMessageType(rows[0].type);
 }
 
 async function rawMessageInfoFromRows(
   rawRows: $ReadOnlyArray<Object>,
   viewer?: Viewer,
   derivedMessages: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
 ): Promise<?RawMessageInfo> {
   let rows = rawRows;
   const dbType = await getDBType();
   if (dbType !== 'mysql5.7') {
     rows = rawRows.map(row => ({
       ...row,
       subthread_permissions: JSON.parse(row.subthread_permissions),
     }));
   }
 
   const type = mostRecentRowType(rows);
   const messageSpec = messageSpecs[type];
 
   if (type === messageTypes.IMAGES || type === messageTypes.MULTIMEDIA) {
     const media = await Promise.all(
       rows.filter(row => row.uploadID).map(mediaFromRow),
     );
     const [row] = rows;
     const localID = localIDFromCreationString(viewer, row.creation);
     invariant(
       messageSpec.rawMessageInfoFromServerDBRow,
       `multimedia message spec should have rawMessageInfoFromServerDBRow`,
     );
     return messageSpec.rawMessageInfoFromServerDBRow(row, {
       media,
       derivedMessages,
       localID,
     });
   }
 
   const row = assertSingleRow(rows);
   const localID = localIDFromCreationString(viewer, row.creation);
   invariant(
     messageSpec.rawMessageInfoFromServerDBRow,
     `message spec ${type} should have rawMessageInfoFromServerDBRow`,
   );
   return messageSpec.rawMessageInfoFromServerDBRow(row, {
     derivedMessages,
     localID,
   });
 }
 
 async function fetchMessageInfos(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
   numberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
   const {
     sqlClause: selectionClause,
     timeFilterData,
   } = parseMessageSelectionCriteria(viewer, criteria);
   const truncationStatuses = {};
 
   const viewerID = viewer.id;
-  const dbType = await getDBType();
-
-  let query;
-  if (dbType === 'mysql5.7') {
-    query = SQL`
-      SELECT * FROM (
-        SELECT x.id, x.content, x.time, x.type, x.user AS creatorID,
-          x.creation, x.subthread_permissions, x.uploadID, x.uploadType,
-          x.uploadSecret, x.uploadExtra,
-          @num := if(
-            @thread = x.thread,
-            if(@message = x.id, @num, @num + 1),
-            1
-          ) AS number,
-          @message := x.id AS messageID,
-          @thread := x.thread AS threadID
-        FROM (SELECT @num := 0, @thread := '', @message := '') init
-        JOIN (
-          SELECT m.id, m.thread, m.user, m.content, m.time, m.type,
-            m.creation, stm.permissions AS subthread_permissions,
-            up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
-            up.extra AS uploadExtra
-          FROM messages m
-          LEFT JOIN uploads up ON up.container = m.id
-          LEFT JOIN memberships mm
-            ON mm.thread = m.thread AND mm.user = ${viewerID}
-          LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
-            AND stm.thread = m.content AND stm.user = ${viewerID}
-          WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
-    `;
-    query.append(selectionClause);
-    // - We specify a ridiculously high LIMIT here to force MariaDB to maintain
-    //   the ORDER BY. Otherwise the query optimizer will assume that the order
-    //   doesn't matter because the outer query doesn't have an ORDER BY.
-    // - Setting an ORDER BY on the outer query won't work because our quirky
-    //   counting logic in the SELECT would be executed before the ORDER, on the
-    //   unsorted results from the inner query.
-    // - More details available here:
-    //   https://mariadb.com/kb/en/why-is-order-by-in-a-from-subquery-ignored/
-    query.append(SQL`
-          ORDER BY m.thread, m.time DESC, m.id DESC
-          LIMIT 18446744073709551615
-        ) x
-      ) y
-      WHERE y.number <= ${numberPerThread}
-    `);
-  } else {
-    query = SQL`
-      WITH thread_window AS (
-        SELECT m.id, m.thread AS threadID, m.user AS creatorID, m.content,
-          m.time, m.type, m.creation, stm.permissions AS subthread_permissions,
+  const query = SQL`
+    SELECT * FROM (
+      SELECT x.id, x.content, x.time, x.type, x.user AS creatorID,
+        x.creation, x.subthread_permissions, x.uploadID, x.uploadType,
+        x.uploadSecret, x.uploadExtra,
+        @num := if(
+          @thread = x.thread,
+          if(@message = x.id, @num, @num + 1),
+          1
+        ) AS number,
+        @message := x.id AS messageID,
+        @thread := x.thread AS threadID
+      FROM (SELECT @num := 0, @thread := '', @message := '') init
+      JOIN (
+        SELECT m.id, m.thread, m.user, m.content, m.time, m.type,
+          m.creation, stm.permissions AS subthread_permissions,
           up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
-          up.extra AS uploadExtra,
-          ROW_NUMBER() OVER (
-            PARTITION BY threadID ORDER BY m.time DESC, m.id DESC
-          ) n
+          up.extra AS uploadExtra
         FROM messages m
         LEFT JOIN uploads up ON up.container = m.id
         LEFT JOIN memberships mm
           ON mm.thread = m.thread AND mm.user = ${viewerID}
         LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
           AND stm.thread = m.content AND stm.user = ${viewerID}
         WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
-    `;
-    query.append(selectionClause);
-    query.append(SQL`
-      )
-      SELECT * FROM thread_window WHERE n <= ${numberPerThread};
-    `);
-  }
+  `;
+  query.append(selectionClause);
+  // - We specify a ridiculously high LIMIT here to force MariaDB to maintain
+  //   the ORDER BY. Otherwise the query optimizer will assume that the order
+  //   doesn't matter because the outer query doesn't have an ORDER BY.
+  // - Setting an ORDER BY on the outer query won't work because our quirky
+  //   counting logic in the SELECT would be executed before the ORDER, on the
+  //   unsorted results from the inner query.
+  // - More details available here:
+  //   https://mariadb.com/kb/en/why-is-order-by-in-a-from-subquery-ignored/
+  query.append(SQL`
+        ORDER BY m.thread, m.time DESC, m.id DESC
+        LIMIT 18446744073709551615
+      ) x
+    ) y
+    WHERE y.number <= ${numberPerThread}
+  `);
 
   const [result] = await dbQuery(query);
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   const messages = await parseMessageSQLResult(result, derivedMessages, viewer);
 
   const rawMessageInfos = [];
   const threadToMessageCount = new Map();
   for (const message of messages) {
     const { rawMessageInfo } = message;
     rawMessageInfos.push(rawMessageInfo);
     const { threadID } = rawMessageInfo;
     const currentCountValue = threadToMessageCount.get(threadID);
     const currentCount = currentCountValue ? currentCountValue : 0;
     threadToMessageCount.set(threadID, currentCount + 1);
   }
 
   for (const [threadID, messageCount] of threadToMessageCount) {
     // If we matched the exact amount we limited to, we're probably truncating
     // our result set. By setting TRUNCATED here, we tell the client that the
     // result set might not be continguous with what's already in their
     // MessageStore. More details about TRUNCATED can be found in
     // lib/types/message-types.js
     if (messageCount >= numberPerThread) {
       // We won't set TRUNCATED if a cursor was specified for a given thread,
       // since then the result is guaranteed to be contiguous with what the
       // client has
       if (criteria.threadCursors && criteria.threadCursors[threadID]) {
         truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
       } else {
         truncationStatuses[threadID] = messageTruncationStatus.TRUNCATED;
       }
       continue;
     }
     const hasTimeFilter = hasTimeFilterForThread(timeFilterData, threadID);
     if (!hasTimeFilter) {
       // If there is no time filter for a given thread, and there are fewer
       // messages returned than the max we queried for a given thread, we can
       // conclude that our result set includes all messages for that thread
       truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
     }
   }
 
   for (const rawMessageInfo of rawMessageInfos) {
     if (messageSpecs[rawMessageInfo.type].startsThread) {
       truncationStatuses[rawMessageInfo.threadID] =
         messageTruncationStatus.EXHAUSTIVE;
     }
   }
 
   for (const threadID in criteria.threadCursors) {
     const truncationStatus = truncationStatuses[threadID];
     if (truncationStatus !== null && truncationStatus !== undefined) {
       continue;
     }
     const hasTimeFilter = hasTimeFilterForThread(timeFilterData, threadID);
     if (!hasTimeFilter) {
       // If there is no time filter for a given thread, and zero messages were
       // returned, we can conclude that this thread has zero messages. This is
       // a case of database corruption that should not be possible, but likely
       // we have some threads like this on prod (either due to some transient
       // issues or due to old buggy code)
       truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
     } else {
       // If this thread was explicitly queried for, and we got no results, but
       // we can't conclude that it's EXHAUSTIVE, then we'll set to UNCHANGED.
       truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
     }
   }
 
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
 
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
 function hasTimeFilterForThread(
   timeFilterData: TimeFilterData,
   threadID: string,
 ) {
   if (timeFilterData.timeFilter === 'ALL') {
     return true;
   } else if (timeFilterData.timeFilter === 'NONE') {
     return false;
   } else if (timeFilterData.timeFilter === 'ALL_EXCEPT_EXCLUDED') {
     return !timeFilterData.excludedFromTimeFilter.has(threadID);
   } else {
     invariant(
       false,
       `unrecognized timeFilter type ${timeFilterData.timeFilter}`,
     );
   }
 }
 
 type TimeFilterData =
   | { +timeFilter: 'ALL' | 'NONE' }
   | {
       +timeFilter: 'ALL_EXCEPT_EXCLUDED',
       +excludedFromTimeFilter: $ReadOnlySet<string>,
     };
 type ParsedMessageSelectionCriteria = {
   +sqlClause: SQLStatementType,
   +timeFilterData: TimeFilterData,
 };
 function parseMessageSelectionCriteria(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
 ): ParsedMessageSelectionCriteria {
   const minMessageTime = Date.now() - defaultMaxMessageAge;
   const shouldApplyTimeFilter = hasMinCodeVersion(viewer.platformDetails, 130);
 
   let globalTimeFilter;
   if (criteria.newerThan) {
     globalTimeFilter = SQL`m.time > ${criteria.newerThan}`;
   } else if (!criteria.threadCursors && shouldApplyTimeFilter) {
     globalTimeFilter = SQL`m.time > ${minMessageTime}`;
   }
 
   const threadConditions = [];
   if (
     criteria.joinedThreads === true &&
     shouldApplyTimeFilter &&
     !globalTimeFilter
   ) {
     threadConditions.push(SQL`(mm.role > 0 AND m.time > ${minMessageTime})`);
   } else if (criteria.joinedThreads === true) {
     threadConditions.push(SQL`mm.role > 0`);
   }
   if (criteria.threadCursors) {
     for (const threadID in criteria.threadCursors) {
       const cursor = criteria.threadCursors[threadID];
       if (cursor) {
         threadConditions.push(
           SQL`(m.thread = ${threadID} AND m.id < ${cursor})`,
         );
       } else {
         threadConditions.push(SQL`m.thread = ${threadID}`);
       }
     }
   }
   if (threadConditions.length === 0) {
     throw new ServerError('internal_error');
   }
   const threadClause = mergeOrConditions(threadConditions);
 
   let timeFilterData;
   if (globalTimeFilter) {
     timeFilterData = { timeFilter: 'ALL' };
   } else if (!shouldApplyTimeFilter) {
     timeFilterData = { timeFilter: 'NONE' };
   } else {
     invariant(
       criteria.threadCursors,
       'ALL_EXCEPT_EXCLUDED should correspond to threadCursors being set',
     );
     const excludedFromTimeFilter = new Set(Object.keys(criteria.threadCursors));
     timeFilterData = {
       timeFilter: 'ALL_EXCEPT_EXCLUDED',
       excludedFromTimeFilter,
     };
   }
 
   const conditions = [globalTimeFilter, threadClause].filter(Boolean);
   const sqlClause = mergeAndConditions(conditions);
 
   return { sqlClause, timeFilterData };
 }
 
 function messageSelectionCriteriaToInitialTruncationStatuses(
   criteria: MessageSelectionCriteria,
   defaultTruncationStatus: MessageTruncationStatus,
 ) {
   const truncationStatuses = {};
   if (criteria.threadCursors) {
     for (const threadID in criteria.threadCursors) {
       truncationStatuses[threadID] = defaultTruncationStatus;
     }
   }
   return truncationStatuses;
 }
 
 async function fetchMessageInfosSince(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
   maxNumberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
   const { sqlClause: selectionClause } = parseMessageSelectionCriteria(
     viewer,
     criteria,
   );
   const truncationStatuses = messageSelectionCriteriaToInitialTruncationStatuses(
     criteria,
     messageTruncationStatus.UNCHANGED,
   );
 
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type,
       m.creation, m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up ON up.container = m.id
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = ${viewerID}
     WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
   query.append(selectionClause);
   query.append(SQL`
     ORDER BY m.thread, m.time DESC, m.id DESC
   `);
   const [result] = await dbQuery(query);
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   const messages = await parseMessageSQLResult(result, derivedMessages, viewer);
 
   const rawMessageInfos = [];
   let currentThreadID = null;
   let numMessagesForCurrentThreadID = 0;
   for (const message of messages) {
     const { rawMessageInfo } = message;
     const { threadID } = rawMessageInfo;
     if (threadID !== currentThreadID) {
       currentThreadID = threadID;
       numMessagesForCurrentThreadID = 1;
       truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
     } else {
       numMessagesForCurrentThreadID++;
     }
     if (numMessagesForCurrentThreadID <= maxNumberPerThread) {
       if (messageSpecs[rawMessageInfo.type].startsThread) {
         truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
       }
       rawMessageInfos.push(rawMessageInfo);
     } else if (numMessagesForCurrentThreadID === maxNumberPerThread + 1) {
       truncationStatuses[threadID] = messageTruncationStatus.TRUNCATED;
     }
   }
 
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
 
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
 function getMessageFetchResultFromRedisMessages(
   viewer: Viewer,
   rawMessageInfos: $ReadOnlyArray<RawMessageInfo>,
 ): FetchMessageInfosResult {
   const truncationStatuses = {};
   for (const rawMessageInfo of rawMessageInfos) {
     truncationStatuses[rawMessageInfo.threadID] =
       messageTruncationStatus.UNCHANGED;
   }
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
 async function fetchMessageInfoForLocalID(
   viewer: Viewer,
   localID: ?string,
 ): Promise<?RawMessageInfo> {
   if (!localID || !viewer.hasSessionInfo) {
     return null;
   }
   const creation = creationString(viewer, localID);
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation,
       m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up ON up.container = m.id
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = ${viewerID}
     WHERE m.user = ${viewerID} AND m.creation = ${creation} AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE
   `;
 
   const [result] = await dbQuery(query);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return await rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 const entryIDExtractString = '$.entryID';
 async function fetchMessageInfoForEntryAction(
   viewer: Viewer,
   messageType: MessageType,
   entryID: string,
   threadID: string,
 ): Promise<?RawMessageInfo> {
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation,
       m.user AS creatorID, up.id AS uploadID, up.type AS uploadType,
       up.secret AS uploadSecret, up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up ON up.container = m.id
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     WHERE m.user = ${viewerID} AND m.thread = ${threadID} AND
       m.type = ${messageType} AND
       JSON_EXTRACT(m.content, ${entryIDExtractString}) = ${entryID} AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE
   `;
 
   const [result] = await dbQuery(query);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return await rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 async function fetchMessageRowsByIDs(messageIDs: $ReadOnlyArray<string>) {
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation, 
       m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret, 
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up ON up.container = m.id
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = m.user
     WHERE m.id IN (${messageIDs})
   `;
   const [result] = await dbQuery(query);
   return result;
 }
 
 async function fetchDerivedMessages(
   rows: $ReadOnlyArray<Object>,
   viewer?: Viewer,
 ): Promise<
   $ReadOnlyMap<string, RawComposableMessageInfo | RawRobotextMessageInfo>,
 > {
   const requiredIDs = new Set<string>();
   for (const row of rows) {
     if (row.type === messageTypes.SIDEBAR_SOURCE) {
       const content = JSON.parse(row.content);
       requiredIDs.add(content.sourceMessageID);
     }
   }
 
   const messagesByID = new Map<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >();
   if (requiredIDs.size === 0) {
     return messagesByID;
   }
 
   const result = await fetchMessageRowsByIDs([...requiredIDs]);
   const messages = await parseMessageSQLResult(result, new Map(), viewer);
 
   for (const message of messages) {
     const { rawMessageInfo } = message;
     if (rawMessageInfo.id) {
       invariant(
         rawMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
         'SIDEBAR_SOURCE should not point to a SIDEBAR_SOURCE',
       );
       messagesByID.set(rawMessageInfo.id, rawMessageInfo);
     }
   }
   return messagesByID;
 }
 
 async function fetchMessageInfoByID(
   viewer?: Viewer,
   messageID: string,
 ): Promise<?RawMessageInfo> {
   const result = await fetchMessageRowsByIDs([messageID]);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return await rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 export {
   fetchCollapsableNotifs,
   fetchMessageInfos,
   fetchMessageInfosSince,
   getMessageFetchResultFromRedisMessages,
   fetchMessageInfoForLocalID,
   fetchMessageInfoForEntryAction,
   fetchMessageInfoByID,
 };