From 1b7e4e047cdede30447d01247dcbf050f65f5b23 Mon Sep 17 00:00:00 2001
From: Alex Hart <alex@signal.org>
Date: Tue, 24 Jan 2023 09:59:01 -0400
Subject: [PATCH] Introduce ManyToMany table for group membership.

---
 .idea/codeStyles/Project.xml                  |   2 -
 .../SafetyNumberChangeDialogPreviewer.kt      |   2 +-
 .../securesms/database/GroupTableTest.kt      | 213 +++++++++++
 .../SafetyNumberBottomSheetRepositoryTest.kt  |  10 +-
 .../securesms/database/GroupTable.kt          | 331 ++++++++++--------
 .../securesms/database/SignalDatabase.kt      |   2 +-
 .../securesms/database/ThreadTable.kt         |  11 +-
 .../helpers/SignalDatabaseMigrations.kt       |   7 +-
 .../V172_GroupMembershipMigration.kt          |  65 ++++
 .../securesms/jobs/MmsDownloadJob.java        |   2 +-
 .../securesms/database/GV2Transformer.kt      |   6 +-
 11 files changed, 486 insertions(+), 165 deletions(-)
 create mode 100644 app/src/androidTest/java/org/thoughtcrime/securesms/database/GroupTableTest.kt
 create mode 100644 app/src/main/java/org/thoughtcrime/securesms/database/helpers/migration/V172_GroupMembershipMigration.kt

diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index b0b653d08b..f4d066945d 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -48,8 +48,6 @@
           <package name="io.ktor" alias="false" withSubpackages="true" />
         </value>
       </option>
-      <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
-      <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
     </JetCodeStyleSettings>
     <codeStyleSettings language="HTML">
       <indentOptions>
diff --git a/app/src/androidTest/java/org/thoughtcrime/securesms/conversation/SafetyNumberChangeDialogPreviewer.kt b/app/src/androidTest/java/org/thoughtcrime/securesms/conversation/SafetyNumberChangeDialogPreviewer.kt
index 5a544664ac..7adcb2b950 100644
--- a/app/src/androidTest/java/org/thoughtcrime/securesms/conversation/SafetyNumberChangeDialogPreviewer.kt
+++ b/app/src/androidTest/java/org/thoughtcrime/securesms/conversation/SafetyNumberChangeDialogPreviewer.kt
@@ -64,7 +64,7 @@ class SafetyNumberChangeDialogPreviewer {
       SafetyNumberBottomSheet
         .forIdentityRecordsAndDestinations(
           identityRecords = ApplicationDependencies.getProtocolStore().aci().identities().getIdentityRecords(othersRecipients).identityRecords,
-          destinations = listOf(ContactSearchKey.RecipientSearchKey.Story(myStoryRecipientId))
+          destinations = listOf(ContactSearchKey.RecipientSearchKey(myStoryRecipientId, true))
         )
         .show(conversationActivity.supportFragmentManager)
     }
diff --git a/app/src/androidTest/java/org/thoughtcrime/securesms/database/GroupTableTest.kt b/app/src/androidTest/java/org/thoughtcrime/securesms/database/GroupTableTest.kt
new file mode 100644
index 0000000000..7f32ecf0c0
--- /dev/null
+++ b/app/src/androidTest/java/org/thoughtcrime/securesms/database/GroupTableTest.kt
@@ -0,0 +1,213 @@
+package org.thoughtcrime.securesms.database
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotEquals
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.signal.core.util.delete
+import org.signal.core.util.readToList
+import org.signal.core.util.requireLong
+import org.signal.core.util.withinTransaction
+import org.signal.libsignal.zkgroup.groups.GroupMasterKey
+import org.signal.storageservice.protos.groups.Member
+import org.signal.storageservice.protos.groups.local.DecryptedGroup
+import org.signal.storageservice.protos.groups.local.DecryptedMember
+import org.thoughtcrime.securesms.groups.GroupId
+import org.thoughtcrime.securesms.recipients.Recipient
+import org.thoughtcrime.securesms.recipients.RecipientId
+import org.thoughtcrime.securesms.testing.SignalActivityRule
+import java.security.SecureRandom
+import kotlin.random.Random
+
+class GroupTableTest {
+
+  @get:Rule
+  val harness = SignalActivityRule()
+
+  private lateinit var groupTable: GroupTable
+
+  @Before
+  fun setUp() {
+    groupTable = SignalDatabase.groups
+
+    groupTable.writableDatabase.delete(GroupTable.TABLE_NAME).run()
+    groupTable.writableDatabase.delete(GroupTable.MembershipTable.TABLE_NAME).run()
+  }
+
+  @Test
+  fun whenICreateGroupV2_thenIExpectMemberRowsPopulated() {
+    val groupId = insertPushGroup()
+
+    //language=sql
+    val members: List<RecipientId> = groupTable.writableDatabase.query(
+      """
+      SELECT ${GroupTable.MembershipTable.RECIPIENT_ID} 
+      FROM ${GroupTable.MembershipTable.TABLE_NAME}
+      WHERE ${GroupTable.MembershipTable.GROUP_ID} = "${groupId.serialize()}"
+      """.trimIndent()
+    ).readToList {
+      RecipientId.from(it.requireLong(GroupTable.RECIPIENT_ID))
+    }
+
+    assertEquals(2, members.size)
+  }
+
+  @Test
+  fun givenAGroupV2_whenIGetGroupsContainingMember_thenIExpectGroup() {
+    val groupId = insertPushGroup()
+    insertThread(groupId)
+
+    val groups = groupTable.getGroupsContainingMember(harness.others[0], false)
+
+    assertEquals(1, groups.size)
+    assertEquals(groupId, groups[0].id)
+  }
+
+  @Test
+  fun givenAnMmsGroup_whenIGetMembers_thenIExpectAllMembers() {
+    val groupId = insertMmsGroup()
+
+    val groups = groupTable.getGroupMemberIds(groupId, GroupTable.MemberSet.FULL_MEMBERS_INCLUDING_SELF)
+
+    assertEquals(2, groups.size)
+  }
+
+  @Test
+  fun givenGroups_whenIQueryGroupsByMembership_thenIExpectBothGroups() {
+    insertPushGroup()
+    insertMmsGroup(members = listOf(harness.others[1]))
+
+    val groups = groupTable.queryGroupsByMembership(
+      setOf(harness.self.id, harness.others[1]),
+      includeInactive = false,
+      excludeV1 = false,
+      excludeMms = false
+    )
+
+    assertEquals(2, groups.cursor?.count)
+  }
+
+  @Test
+  fun givenGroups_whenIGetGroups_thenIExpectBothGroups() {
+    insertPushGroup()
+    insertMmsGroup(members = listOf(harness.others[1]))
+
+    val groups = groupTable.getGroups()
+
+    assertEquals(2, groups.cursor?.count)
+  }
+
+  @Test
+  fun givenAGroup_whenIGetGroup_thenIExpectGroup() {
+    val v2Group = insertPushGroup()
+    insertThread(v2Group)
+
+    val groupRecord = groupTable.getGroup(v2Group).get()
+    assertEquals(setOf(harness.self.id, harness.others[0]), groupRecord.members.toSet())
+  }
+
+  @Test
+  fun givenAGroupAndARemap_whenIGetGroup_thenIExpectRemap() {
+    val v2Group = insertPushGroup()
+    insertThread(v2Group)
+
+    groupTable.writableDatabase.withinTransaction {
+      RemappedRecords.getInstance().addRecipient(harness.others[0], harness.others[1])
+    }
+
+    val groupRecord = groupTable.getGroup(v2Group).get()
+    assertEquals(groupRecord.members.toSet(), setOf(harness.self.id, harness.others[1]))
+  }
+
+  @Test
+  fun givenAGroupAndMember_whenIIsCurrentMember_thenIExpectTrue() {
+    val v2Group = insertPushGroup()
+
+    val actual = groupTable.isCurrentMember(v2Group.requirePush(), harness.others[0])
+
+    assertTrue(actual)
+  }
+
+  @Test
+  fun givenAGroupAndMember_whenIRemove_thenIExpectNotAMember() {
+    val v2Group = insertPushGroup()
+
+    groupTable.remove(v2Group, harness.others[0])
+    val actual = groupTable.isCurrentMember(v2Group.requirePush(), harness.others[0])
+
+    assertFalse(actual)
+  }
+
+  @Test
+  fun givenAGroupAndNonMember_whenIIsCurrentMember_thenIExpectFalse() {
+    val v2Group = insertPushGroup()
+
+    val actual = groupTable.isCurrentMember(v2Group.requirePush(), harness.others[1])
+
+    assertFalse(actual)
+  }
+
+  @Test
+  fun givenAGroup_whenIUpdateMembers_thenIExpectUpdatedMembers() {
+    val v2Group = insertPushGroup()
+    groupTable.updateMembers(v2Group, listOf(harness.self.id, harness.others[1]))
+    val groupRecord = groupTable.getGroup(v2Group)
+
+    assertEquals(setOf(harness.self.id, harness.others[1]), groupRecord.get().members.toSet())
+  }
+
+  @Test
+  fun givenAnMmsGroup_whenIGetOrCreateMmsGroup_thenIExpectMyMmsGroup() {
+    val members: List<RecipientId> = listOf(harness.self.id, harness.others[0])
+    val other = insertMmsGroup(members + listOf(harness.others[1]))
+    val mmsGroup = insertMmsGroup(members)
+    val actual = groupTable.getOrCreateMmsGroupForMembers(members.toSet())
+
+    assertNotEquals(other, actual)
+    assertEquals(mmsGroup, actual)
+  }
+
+  private fun insertThread(groupId: GroupId): Long {
+    val groupRecipient = SignalDatabase.recipients.getByGroupId(groupId).get()
+    return SignalDatabase.threads.getOrCreateThreadIdFor(Recipient.resolved(groupRecipient))
+  }
+
+  private fun insertMmsGroup(members: List<RecipientId> = listOf(harness.self.id, harness.others[0])): GroupId {
+    val id = GroupId.createMms(SecureRandom())
+    groupTable.create(
+      id,
+      null,
+      members.apply {
+        println("Creating a group with ${members.size} members")
+      }
+    )
+
+    return id
+  }
+
+  private fun insertPushGroup(): GroupId {
+    val groupMasterKey = GroupMasterKey(Random.nextBytes(GroupMasterKey.SIZE))
+    val decryptedGroupState = DecryptedGroup.newBuilder()
+      .addAllMembers(
+        listOf(
+          DecryptedMember.newBuilder()
+            .setUuid(harness.self.requireServiceId().toByteString())
+            .setJoinedAtRevision(0)
+            .setRole(Member.Role.DEFAULT)
+            .build(),
+          DecryptedMember.newBuilder()
+            .setUuid(Recipient.resolved(harness.others[0]).requireServiceId().toByteString())
+            .setJoinedAtRevision(0)
+            .setRole(Member.Role.DEFAULT)
+            .build()
+        )
+      )
+      .setRevision(0)
+      .build()
+
+    return groupTable.create(groupMasterKey, decryptedGroupState)
+  }
+}
diff --git a/app/src/androidTest/java/org/thoughtcrime/securesms/safety/SafetyNumberBottomSheetRepositoryTest.kt b/app/src/androidTest/java/org/thoughtcrime/securesms/safety/SafetyNumberBottomSheetRepositoryTest.kt
index 1f9f172135..ca87741ced 100644
--- a/app/src/androidTest/java/org/thoughtcrime/securesms/safety/SafetyNumberBottomSheetRepositoryTest.kt
+++ b/app/src/androidTest/java/org/thoughtcrime/securesms/safety/SafetyNumberBottomSheetRepositoryTest.kt
@@ -27,7 +27,7 @@ class SafetyNumberBottomSheetRepositoryTest {
   @Test
   fun givenIOnlyHave1to1Destinations_whenIGetBuckets_thenIOnlyHaveContactsBucketContainingAllRecipients() {
     val recipients = harness.others
-    val destinations = harness.others.map { ContactSearchKey.RecipientSearchKey.KnownRecipient(it) }
+    val destinations = harness.others.map { ContactSearchKey.RecipientSearchKey(it, false) }
 
     val result = subjectUnderTest.getBuckets(recipients, destinations).test()
 
@@ -42,7 +42,7 @@ class SafetyNumberBottomSheetRepositoryTest {
   fun givenIOnlyHaveASingle1to1Destination_whenIGetBuckets_thenIOnlyHaveContactsBucketContainingAllRecipients() {
     // GIVEN
     val recipients = harness.others
-    val destination = harness.others.take(1).map { ContactSearchKey.RecipientSearchKey.KnownRecipient(it) }
+    val destination = harness.others.take(1).map { ContactSearchKey.RecipientSearchKey(it, false) }
 
     // WHEN
     val result = subjectUnderTest.getBuckets(recipients, destination).test(1)
@@ -59,7 +59,7 @@ class SafetyNumberBottomSheetRepositoryTest {
     // GIVEN
     val distributionListMembers = harness.others.take(5)
     val distributionList = SignalDatabase.distributionLists.createList("ListA", distributionListMembers)!!
-    val destinationKey = ContactSearchKey.RecipientSearchKey.Story(SignalDatabase.distributionLists.getRecipientId(distributionList)!!)
+    val destinationKey = ContactSearchKey.RecipientSearchKey(SignalDatabase.distributionLists.getRecipientId(distributionList)!!, true)
 
     // WHEN
     val result = subjectUnderTest.getBuckets(harness.others, listOf(destinationKey)).test(1)
@@ -82,7 +82,7 @@ class SafetyNumberBottomSheetRepositoryTest {
     val distributionListMembers = harness.others.take(5)
     val toRemove = distributionListMembers.last()
     val distributionList = SignalDatabase.distributionLists.createList("ListA", distributionListMembers)!!
-    val destinationKey = ContactSearchKey.RecipientSearchKey.Story(SignalDatabase.distributionLists.getRecipientId(distributionList)!!)
+    val destinationKey = ContactSearchKey.RecipientSearchKey(SignalDatabase.distributionLists.getRecipientId(distributionList)!!, true)
     val testSubscriber = subjectUnderTest.getBuckets(distributionListMembers, listOf(destinationKey)).test(2)
     testScheduler.triggerActions()
 
@@ -108,7 +108,7 @@ class SafetyNumberBottomSheetRepositoryTest {
     // GIVEN
     val distributionListMembers = harness.others.take(5)
     val distributionList = SignalDatabase.distributionLists.createList("ListA", distributionListMembers)!!
-    val destinationKey = ContactSearchKey.RecipientSearchKey.Story(SignalDatabase.distributionLists.getRecipientId(distributionList)!!)
+    val destinationKey = ContactSearchKey.RecipientSearchKey(SignalDatabase.distributionLists.getRecipientId(distributionList)!!, true)
     val testSubscriber = subjectUnderTest.getBuckets(distributionListMembers, listOf(destinationKey)).test(2)
     testScheduler.triggerActions()
 
diff --git a/app/src/main/java/org/thoughtcrime/securesms/database/GroupTable.kt b/app/src/main/java/org/thoughtcrime/securesms/database/GroupTable.kt
index 9901c9abd7..f5576f7516 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/database/GroupTable.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/database/GroupTable.kt
@@ -13,6 +13,7 @@ import org.signal.core.util.SqlUtil.appendArg
 import org.signal.core.util.SqlUtil.buildArgs
 import org.signal.core.util.SqlUtil.buildCaseInsensitiveGlobPattern
 import org.signal.core.util.SqlUtil.buildCollectionQuery
+import org.signal.core.util.delete
 import org.signal.core.util.exists
 import org.signal.core.util.isAbsent
 import org.signal.core.util.logging.Log
@@ -50,7 +51,6 @@ import org.thoughtcrime.securesms.jobs.RequestGroupV2InfoJob
 import org.thoughtcrime.securesms.keyvalue.SignalStore
 import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.recipients.RecipientId
-import org.thoughtcrime.securesms.util.Util
 import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil
 import org.whispersystems.signalservice.api.groupsv2.GroupChangeReconstruct
 import org.whispersystems.signalservice.api.messages.SignalServiceAttachmentPointer
@@ -58,11 +58,7 @@ import org.whispersystems.signalservice.api.push.DistributionId
 import org.whispersystems.signalservice.api.push.ServiceId
 import org.whispersystems.signalservice.api.util.UuidUtil
 import java.io.Closeable
-import java.lang.AssertionError
-import java.lang.IllegalArgumentException
-import java.lang.IllegalStateException
 import java.security.SecureRandom
-import java.util.ArrayList
 import java.util.Optional
 import java.util.UUID
 import java.util.stream.Collectors
@@ -72,12 +68,13 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
   companion object {
     private val TAG = Log.tag(GroupTable::class.java)
 
+    const val MEMBER_GROUP_CONCAT = "member_group_concat"
+
     const val TABLE_NAME = "groups"
     const val ID = "_id"
     const val GROUP_ID = "group_id"
     const val RECIPIENT_ID = "recipient_id"
     const val TITLE = "title"
-    const val MEMBERS = "members"
     const val AVATAR_ID = "avatar_id"
     const val AVATAR_KEY = "avatar_key"
     const val AVATAR_CONTENT_TYPE = "avatar_content_type"
@@ -112,7 +109,6 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
         $GROUP_ID TEXT, 
         $RECIPIENT_ID INTEGER,
         $TITLE TEXT,
-        $MEMBERS TEXT,
         $AVATAR_ID INTEGER, 
         $AVATAR_KEY BLOB,
         $AVATAR_CONTENT_TYPE TEXT, 
@@ -145,7 +141,6 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       GROUP_ID,
       RECIPIENT_ID,
       TITLE,
-      MEMBERS,
       UNMIGRATED_V1_MEMBERS,
       AVATAR_ID,
       AVATAR_KEY,
@@ -165,43 +160,77 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       .filterNot { it == RECIPIENT_ID }
       .map { columnName: String -> "$TABLE_NAME.$columnName" }
       .toList()
+
+    //language=sql
+    private val JOINED_GROUP_SELECT = """
+      SELECT 
+        DISTINCT $TABLE_NAME.*, 
+        GROUP_CONCAT(${MembershipTable.TABLE_NAME}.${MembershipTable.RECIPIENT_ID}) as $MEMBER_GROUP_CONCAT
+      FROM $TABLE_NAME          
+      INNER JOIN ${MembershipTable.TABLE_NAME} ON ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID} = $TABLE_NAME.$GROUP_ID
+    """.toSingleLine()
+
+    val CREATE_TABLES = arrayOf(CREATE_TABLE, MembershipTable.CREATE_TABLE)
+  }
+
+  class MembershipTable(context: Context, databaseHelper: SignalDatabase) : DatabaseTable(context, databaseHelper) {
+    companion object {
+      const val TABLE_NAME = "group_membership"
+
+      const val ID = "_id"
+      const val GROUP_ID = "group_id"
+      const val RECIPIENT_ID = "recipient_id"
+
+      //language=sql
+      @JvmField
+      val CREATE_TABLE = """
+        CREATE TABLE $TABLE_NAME (
+            $ID INTEGER PRIMARY KEY,
+            $GROUP_ID TEXT NOT NULL,
+            $RECIPIENT_ID INTEGER NOT NULL,
+            UNIQUE($GROUP_ID, $RECIPIENT_ID)
+        )
+      """.toSingleLine()
+    }
   }
 
   fun getGroup(recipientId: RecipientId): Optional<GroupRecord> {
-    readableDatabase
-      .select()
-      .from(TABLE_NAME)
-      .where("$RECIPIENT_ID = ?", recipientId)
-      .run()
-      .use { cursor ->
-        return if (cursor.moveToFirst()) {
-          getGroup(cursor)
-        } else {
-          Optional.empty()
-        }
-      }
+    return getGroup(SqlUtil.Query("$TABLE_NAME.$RECIPIENT_ID = ?", buildArgs(recipientId)))
   }
 
   fun getGroup(groupId: GroupId): Optional<GroupRecord> {
+    return getGroup(SqlUtil.Query("$TABLE_NAME.$GROUP_ID = ?", buildArgs(groupId)))
+  }
+
+  private fun getGroup(query: SqlUtil.Query): Optional<GroupRecord> {
+    //language=sql
+    val select = "$JOINED_GROUP_SELECT WHERE ${query.where} GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}"
+
     readableDatabase
-      .select()
-      .from(TABLE_NAME)
-      .where("$GROUP_ID = ?", groupId.toString())
-      .run()
+      .query(select, query.whereArgs)
       .use { cursor ->
         return if (cursor.moveToFirst()) {
           val groupRecord = getGroup(cursor)
           if (groupRecord.isPresent && RemappedRecords.getInstance().areAnyRemapped(groupRecord.get().members)) {
+            val groupId = groupRecord.get().id
             val remaps = RemappedRecords.getInstance().buildRemapDescription(groupRecord.get().members)
             Log.w(TAG, "Found a group with remapped recipients in it's membership list! Updating the list. GroupId: $groupId, Remaps: $remaps", true)
 
-            val remapped: Collection<RecipientId> = RemappedRecords.getInstance().remap(groupRecord.get().members)
+            val oldToNew: List<Pair<RecipientId, RecipientId?>> = groupRecord.get().members.map {
+              it to RemappedRecords.getInstance().getRecipient(it).orElse(null)
+            }.filterNot { (old, new) -> new == null || old == new }
 
-            val updateCount = writableDatabase
-              .update(TABLE_NAME)
-              .values(MEMBERS to remapped.serialize())
-              .where("$GROUP_ID = ?", groupId)
-              .run()
+            var updateCount = 0
+            if (oldToNew.isNotEmpty()) {
+              writableDatabase.withinTransaction { db ->
+                for ((old, new) in oldToNew) {
+                  updateCount += db.update(MembershipTable.TABLE_NAME)
+                    .values(MembershipTable.RECIPIENT_ID to new!!.serialize())
+                    .where("${MembershipTable.GROUP_ID} = ? AND ${MembershipTable.RECIPIENT_ID} = ?", groupId, old)
+                    .run()
+                }
+              }
+            }
 
             if (updateCount > 0) {
               getGroup(groupId)
@@ -240,33 +269,11 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
    * @return A gv1 group whose expected v2 ID matches the one provided.
    */
   fun getGroupV1ByExpectedV2(gv2Id: GroupId.V2): Optional<GroupRecord> {
-    readableDatabase
-      .select(*GROUP_PROJECTION)
-      .from(TABLE_NAME)
-      .where("$EXPECTED_V2_ID = ?", gv2Id)
-      .run()
-      .use { cursor ->
-        return if (cursor.moveToFirst()) {
-          getGroup(cursor)
-        } else {
-          Optional.empty()
-        }
-      }
+    return getGroup(SqlUtil.Query("$TABLE_NAME.$EXPECTED_V2_ID = ?", buildArgs(gv2Id)))
   }
 
   fun getGroupByDistributionId(distributionId: DistributionId): Optional<GroupRecord> {
-    readableDatabase
-      .select()
-      .from(TABLE_NAME)
-      .where("$DISTRIBUTION_ID = ?", distributionId)
-      .run()
-      .use { cursor ->
-        return if (cursor.moveToFirst()) {
-          getGroup(cursor)
-        } else {
-          Optional.empty()
-        }
-      }
+    return getGroup(SqlUtil.Query("$TABLE_NAME.$DISTRIBUTION_ID = ?", buildArgs(distributionId)))
   }
 
   fun removeUnmigratedV1Members(id: GroupId.V2) {
@@ -338,7 +345,14 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
 
   fun queryGroupsByTitle(inputQuery: String, includeInactive: Boolean, excludeV1: Boolean, excludeMms: Boolean): Reader {
     val query = getGroupQueryWhereStatement(inputQuery, includeInactive, excludeV1, excludeMms)
-    val cursor = databaseHelper.signalReadableDatabase.query(TABLE_NAME, null, query.where, query.whereArgs, null, null, "$TITLE COLLATE NOCASE ASC")
+    val statement = """
+      $JOINED_GROUP_SELECT
+      WHERE ${query.where}
+      GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}
+      ORDER BY $TITLE COLLATE NOCASE ASC
+    """.trimIndent()
+
+    val cursor = databaseHelper.signalReadableDatabase.query(statement, query.whereArgs)
     return Reader(cursor)
   }
 
@@ -353,21 +367,17 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       recipientIds = recipientIds.take(30).toSet()
     }
 
-    val recipientLikeClauses = recipientIds
-      .map { it.toLong() }
-      .map { id -> "($MEMBERS LIKE $id || ',%' OR $MEMBERS LIKE '%,' || $id || ',%' OR $MEMBERS LIKE '%,' || $id)" }
-      .toList()
+    val membershipQuery = SqlUtil.buildSingleCollectionQuery("${MembershipTable.TABLE_NAME}.${MembershipTable.RECIPIENT_ID}", recipientIds)
 
     var query: String
     val queryArgs: Array<String>
-    val membershipQuery = "(" + Util.join(recipientLikeClauses, " OR ") + ")"
 
     if (includeInactive) {
-      query = "$membershipQuery AND ($ACTIVE = ? OR $RECIPIENT_ID IN (SELECT ${ThreadTable.RECIPIENT_ID} FROM ${ThreadTable.TABLE_NAME}))"
-      queryArgs = buildArgs(1)
+      query = "${membershipQuery.where} AND ($ACTIVE = ? OR $TABLE_NAME.$RECIPIENT_ID IN (SELECT ${ThreadTable.RECIPIENT_ID} FROM ${ThreadTable.TABLE_NAME}))"
+      queryArgs = membershipQuery.whereArgs + buildArgs(1)
     } else {
-      query = "$membershipQuery AND $ACTIVE = ?"
-      queryArgs = buildArgs(1)
+      query = "${membershipQuery.where} AND $ACTIVE = ?"
+      queryArgs = membershipQuery.whereArgs + buildArgs(1)
     }
 
     if (excludeV1) {
@@ -378,15 +388,15 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       query += " AND $MMS = 0"
     }
 
-    return Reader(readableDatabase.query(TABLE_NAME, null, query, queryArgs, null, null, null))
+    return Reader(readableDatabase.query("$JOINED_GROUP_SELECT WHERE $query GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}", queryArgs))
   }
 
   private fun queryGroupsByRecency(groupQuery: GroupQuery): Reader {
     val query = getGroupQueryWhereStatement(groupQuery.searchQuery, groupQuery.includeInactive, !groupQuery.includeV1, !groupQuery.includeMms)
     val sql = """
-      SELECT $TABLE_NAME.*
-      FROM $TABLE_NAME LEFT JOIN ${ThreadTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${ThreadTable.TABLE_NAME}.${ThreadTable.RECIPIENT_ID} 
+      $JOINED_GROUP_SELECT
       WHERE ${query.where} 
+      ${"GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}"}
       ORDER BY ${ThreadTable.TABLE_NAME}.${ThreadTable.DATE} DESC
     """.toSingleLine()
 
@@ -407,7 +417,7 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     val caseInsensitiveQuery = buildCaseInsensitiveGlobPattern(inputQuery)
 
     if (includeInactive) {
-      query = "$TITLE GLOB ? AND ($ACTIVE = ? OR $RECIPIENT_ID IN (SELECT ${ThreadTable.RECIPIENT_ID} FROM ${ThreadTable.TABLE_NAME}))"
+      query = "$TITLE GLOB ? AND ($ACTIVE = ? OR $TABLE_NAME.$RECIPIENT_ID IN (SELECT ${ThreadTable.RECIPIENT_ID} FROM ${ThreadTable.TABLE_NAME}))"
       queryArgs = buildArgs(caseInsensitiveQuery, 1)
     } else {
       query = "$TITLE GLOB ? AND $ACTIVE = ?"
@@ -456,23 +466,27 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       }
   }
 
-  fun getOrCreateMmsGroupForMembers(members: List<RecipientId>): GroupId.Mms {
-    val sortedMembers = members.sorted()
+  fun getOrCreateMmsGroupForMembers(members: Set<RecipientId>): GroupId.Mms {
+    //language=sql
+    val statement = """
+      SELECT ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID} as gid
+      FROM ${MembershipTable.TABLE_NAME}
+      INNER JOIN $TABLE_NAME ON ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID} = $TABLE_NAME.$GROUP_ID
+      WHERE ${MembershipTable.TABLE_NAME}.$RECIPIENT_ID IN (${members.joinToString(",") { it.serialize() }}) AND $TABLE_NAME.$MMS = 1
+      GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}
+      HAVING (SELECT COUNT(*) FROM ${MembershipTable.TABLE_NAME} WHERE ${MembershipTable.GROUP_ID} = gid) = ${members.size}
+      ORDER BY ${MembershipTable.TABLE_NAME}.${MembershipTable.ID} ASC
+    """.toSingleLine()
 
-    readableDatabase
-      .select(GROUP_ID)
-      .from(TABLE_NAME)
-      .where("$MEMBERS = ? AND $MMS = ?", sortedMembers.serialize(), 1)
-      .run()
-      .use { cursor ->
-        return if (cursor.moveToNext()) {
-          GroupId.parseOrThrow(cursor.requireNonNullString(GROUP_ID)).requireMms()
-        } else {
-          val groupId = GroupId.createMms(SecureRandom())
-          create(groupId, null, sortedMembers)
-          groupId
-        }
+    return readableDatabase.query(statement).use { cursor ->
+      if (cursor.moveToNext()) {
+        return GroupId.parseOrThrow(cursor.requireNonNullString("gid")).requireMms()
+      } else {
+        val groupId = GroupId.createMms(SecureRandom())
+        create(groupId, null, members)
+        groupId
       }
+    }
   }
 
   @WorkerThread
@@ -493,9 +507,14 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
 
   @WorkerThread
   fun getGroupsContainingMember(recipientId: RecipientId, pushOnly: Boolean, includeInactive: Boolean): List<GroupRecord> {
-    val table = "$TABLE_NAME INNER JOIN ${ThreadTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${ThreadTable.TABLE_NAME}.${ThreadTable.RECIPIENT_ID}"
-    var query = "$MEMBERS LIKE ?"
-    var args = buildArgs("%${recipientId.serialize()}%")
+    //language=sql
+    val table = """
+      $JOINED_GROUP_SELECT
+          INNER JOIN ${ThreadTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${ThreadTable.TABLE_NAME}.${ThreadTable.RECIPIENT_ID}
+    """.toSingleLine()
+
+    var query = "${MembershipTable.TABLE_NAME}.${MembershipTable.RECIPIENT_ID} = ?"
+    var args = buildArgs(recipientId)
     val orderBy = "${ThreadTable.TABLE_NAME}.${ThreadTable.DATE} DESC"
 
     if (pushOnly) {
@@ -509,23 +528,14 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     }
 
     return readableDatabase
-      .query(table, null, query, args, null, null, orderBy)
+      .query("$table WHERE $query GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID} ORDER BY $orderBy".apply { println(this) }, args)
       .readToList { cursor ->
-        val serializedMembers = cursor.requireNonNullString(MEMBERS)
-        if (RecipientId.serializedListContains(serializedMembers, recipientId)) {
-          getGroup(cursor).get()
-        } else {
-          null
-        }
+        getGroup(cursor).get()
       }
-      .filterNotNull()
   }
 
   fun getGroups(): Reader {
-    val cursor = readableDatabase
-      .select()
-      .from(TABLE_NAME)
-      .run()
+    val cursor = readableDatabase.query("$JOINED_GROUP_SELECT GROUP BY ${MembershipTable.TABLE_NAME}.${MembershipTable.GROUP_ID}")
     return Reader(cursor)
   }
 
@@ -648,6 +658,7 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     groupMasterKey: GroupMasterKey?,
     groupState: DecryptedGroup?
   ) {
+    val membershipValues = mutableListOf<ContentValues>()
     val groupRecipientId = recipients.getOrInsertFromGroupId(groupId)
     val members: List<RecipientId> = memberCollection.toSet().sorted()
     var groupMembers: List<RecipientId> = members
@@ -657,7 +668,7 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     values.put(RECIPIENT_ID, groupRecipientId.serialize())
     values.put(GROUP_ID, groupId.toString())
     values.put(TITLE, title)
-    values.put(MEMBERS, members.serialize())
+    membershipValues.addAll(members.toContentValues(groupId))
     values.put(MMS, groupId.isMms)
 
     if (avatar != null) {
@@ -693,14 +704,25 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       values.put(V2_MASTER_KEY, groupMasterKey.serialize())
       values.put(V2_REVISION, groupState.revision)
       values.put(V2_DECRYPTED_GROUP, groupState.toByteArray())
-      values.put(MEMBERS, groupMembers.serialize())
+      membershipValues.clear()
+      membershipValues.addAll(groupMembers.toContentValues(groupId))
     } else {
       if (groupId.isV2) {
         throw AssertionError("V2 group id but no master key")
       }
     }
 
-    writableDatabase.insert(TABLE_NAME, null, values)
+    writableDatabase.withinTransaction { db ->
+      db.insert(TABLE_NAME, null, values)
+      SqlUtil.buildBulkInsert(
+        MembershipTable.TABLE_NAME,
+        arrayOf(MembershipTable.GROUP_ID, MembershipTable.RECIPIENT_ID),
+        membershipValues
+      )
+        .forEach {
+          db.execSQL(it.where, it.whereArgs)
+        }
+    }
 
     if (groupState != null && groupState.hasDisappearingMessagesTimer()) {
       recipients.setExpireMessages(groupRecipientId, groupState.disappearingMessagesTimer.duration)
@@ -829,7 +851,6 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     }
 
     val groupMembers = getV2GroupMembers(decryptedGroup, true)
-    contentValues.put(MEMBERS, groupMembers.serialize())
 
     if (existingGroup.isPresent && existingGroup.get().isV2Group) {
       val change = GroupChangeReconstruct.reconstructGroupChange(existingGroup.get().requireV2GroupProperties().decryptedGroup, decryptedGroup)
@@ -842,11 +863,15 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
       }
     }
 
-    writableDatabase
-      .update(TABLE_NAME)
-      .values(contentValues)
-      .where("$GROUP_ID = ?", groupId.toString())
-      .run()
+    writableDatabase.withinTransaction { database ->
+      database
+        .update(TABLE_NAME)
+        .values(contentValues)
+        .where("$GROUP_ID = ?", groupId.toString())
+        .run()
+
+      performMembershipUpdate(database, groupId, groupMembers)
+    }
 
     if (decryptedGroup.hasDisappearingMessagesTimer()) {
       recipients.setExpireMessages(groupRecipientId, decryptedGroup.disappearingMessagesTimer.duration)
@@ -898,27 +923,24 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
   }
 
   fun updateMembers(groupId: GroupId, members: List<RecipientId>) {
-    writableDatabase
-      .update(TABLE_NAME)
-      .values(
-        MEMBERS to members.sorted().serialize(),
-        ACTIVE to 1
-      )
-      .where("$GROUP_ID = ?", groupId)
-      .run()
+    writableDatabase.withinTransaction { database ->
+      database
+        .update(TABLE_NAME)
+        .values(ACTIVE to 1)
+        .where("$GROUP_ID = ?", groupId)
+        .run()
+
+      performMembershipUpdate(database, groupId, members)
+    }
 
     val groupRecipient = recipients.getOrInsertFromGroupId(groupId)
     Recipient.live(groupRecipient).refresh()
   }
 
   fun remove(groupId: GroupId, source: RecipientId) {
-    val currentMembers: MutableList<RecipientId> = getCurrentMembers(groupId)
-    currentMembers -= source
-
     writableDatabase
-      .update(TABLE_NAME)
-      .values(MEMBERS to currentMembers.serialize())
-      .where("$GROUP_ID = ?", groupId)
+      .delete(MembershipTable.TABLE_NAME)
+      .where("${MembershipTable.GROUP_ID} = ? AND ${MembershipTable.RECIPIENT_ID} = ?", groupId, source)
       .run()
 
     val groupRecipient = recipients.getOrInsertFromGroupId(groupId)
@@ -927,17 +949,34 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
 
   private fun getCurrentMembers(groupId: GroupId): MutableList<RecipientId> {
     return readableDatabase
-      .select(MEMBERS)
-      .from(TABLE_NAME)
-      .where("$GROUP_ID = ?", groupId)
+      .select(MembershipTable.RECIPIENT_ID)
+      .from(MembershipTable.TABLE_NAME)
+      .where("${MembershipTable.GROUP_ID} = ?", groupId)
       .run()
       .readToList { cursor ->
-        val serializedMembers = cursor.requireNonNullString(MEMBERS)
-        return RecipientId.fromSerializedList(serializedMembers)
+        RecipientId.from(cursor.requireLong(MembershipTable.RECIPIENT_ID))
       }
       .toMutableList()
   }
 
+  private fun performMembershipUpdate(database: SQLiteDatabase, groupId: GroupId, members: Collection<RecipientId>) {
+    check(database.inTransaction())
+    database
+      .delete(MembershipTable.TABLE_NAME)
+      .where("${MembershipTable.GROUP_ID} = ?", groupId)
+      .run()
+
+    val inserts = SqlUtil.buildBulkInsert(
+      MembershipTable.TABLE_NAME,
+      arrayOf(MembershipTable.GROUP_ID, MembershipTable.RECIPIENT_ID),
+      members.toContentValues(groupId)
+    )
+
+    inserts.forEach {
+      database.execSQL(it.where, it.whereArgs)
+    }
+  }
+
   fun isActive(groupId: GroupId): Boolean {
     val record = getGroup(groupId)
     return record.isPresent && record.get().isActive
@@ -961,19 +1000,10 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
 
   @WorkerThread
   fun isCurrentMember(groupId: Push, recipientId: RecipientId): Boolean {
-    readableDatabase
-      .select(MEMBERS)
-      .from(TABLE_NAME)
-      .where("$GROUP_ID = ?", groupId)
+    return readableDatabase
+      .exists(MembershipTable.TABLE_NAME)
+      .where("${MembershipTable.GROUP_ID} = ? AND ${MembershipTable.RECIPIENT_ID} = ?", groupId, recipientId)
       .run()
-      .use { cursor ->
-        return if (cursor.moveToFirst()) {
-          val serializedMembers = cursor.requireNonNullString(MEMBERS)
-          RecipientId.serializedListContains(serializedMembers, recipientId)
-        } else {
-          false
-        }
-      }
   }
 
   fun getAllGroupV2Ids(): List<GroupId.V2> {
@@ -1005,15 +1035,13 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
   }
 
   override fun remapRecipient(fromId: RecipientId, toId: RecipientId) {
+    writableDatabase
+      .update(MembershipTable.TABLE_NAME)
+      .values(RECIPIENT_ID to toId.serialize())
+      .where("${MembershipTable.RECIPIENT_ID} = ?", fromId)
+      .run()
+
     for (group in getGroupsContainingMember(fromId, false, true)) {
-      val newMembers: Set<RecipientId> = group.members.toSet() - fromId + toId
-
-      writableDatabase
-        .update(TABLE_NAME)
-        .values(MEMBERS to newMembers.serialize())
-        .where("$RECIPIENT_ID = ?", group.recipientId)
-        .run()
-
       if (group.isV2Group) {
         removeUnmigratedV1Members(group.id.requireV2(), listOf(fromId))
       }
@@ -1042,7 +1070,7 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
           id = GroupId.parseOrThrow(cursor.requireNonNullString(GROUP_ID)),
           recipientId = RecipientId.from(cursor.requireNonNullString(RECIPIENT_ID)),
           title = cursor.requireString(TITLE),
-          serializedMembers = cursor.requireString(MEMBERS),
+          serializedMembers = cursor.requireString(MEMBER_GROUP_CONCAT),
           serializedUnmigratedV1Members = cursor.requireString(UNMIGRATED_V1_MEMBERS),
           avatarId = cursor.requireLong(AVATAR_ID),
           avatarKey = cursor.requireBlob(AVATAR_KEY),
@@ -1252,6 +1280,15 @@ class GroupTable(context: Context?, databaseHelper: SignalDatabase?) : DatabaseT
     return RecipientId.toSerializedList(this)
   }
 
+  private fun Collection<RecipientId>.toContentValues(groupId: GroupId): List<ContentValues> {
+    return map {
+      contentValuesOf(
+        MembershipTable.GROUP_ID to groupId.serialize(),
+        MembershipTable.RECIPIENT_ID to it.serialize()
+      )
+    }
+  }
+
   private fun uuidsToRecipientIds(uuids: List<UUID>): MutableList<RecipientId> {
     return uuids
       .asSequence()
diff --git a/app/src/main/java/org/thoughtcrime/securesms/database/SignalDatabase.kt b/app/src/main/java/org/thoughtcrime/securesms/database/SignalDatabase.kt
index d037f78c54..f21a8f3867 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/database/SignalDatabase.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/database/SignalDatabase.kt
@@ -86,7 +86,7 @@ open class SignalDatabase(private val context: Application, databaseSecret: Data
     db.execSQL(IdentityTable.CREATE_TABLE)
     db.execSQL(DraftTable.CREATE_TABLE)
     db.execSQL(PushTable.CREATE_TABLE)
-    db.execSQL(GroupTable.CREATE_TABLE)
+    executeStatements(db, GroupTable.CREATE_TABLES)
     db.execSQL(RecipientTable.CREATE_TABLE)
     db.execSQL(GroupReceiptTable.CREATE_TABLE)
     db.execSQL(OneTimePreKeyTable.CREATE_TABLE)
diff --git a/app/src/main/java/org/thoughtcrime/securesms/database/ThreadTable.kt b/app/src/main/java/org/thoughtcrime/securesms/database/ThreadTable.kt
index 1a0fc83a7e..a5983f1146 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/database/ThreadTable.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/database/ThreadTable.kt
@@ -1610,12 +1610,17 @@ class ThreadTable(context: Context, databaseHelper: SignalDatabase) : DatabaseTa
   private fun createQuery(where: String, orderBy: String, offset: Long, limit: Long): String {
     val projection = COMBINED_THREAD_RECIPIENT_GROUP_PROJECTION.joinToString(separator = ",")
 
+    //language=sql
     var query = """
-      SELECT $projection 
+      SELECT $projection, ${GroupTable.MEMBER_GROUP_CONCAT}
       FROM $TABLE_NAME 
         LEFT OUTER JOIN ${RecipientTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${RecipientTable.TABLE_NAME}.${RecipientTable.ID} 
-        LEFT OUTER JOIN ${GroupTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${GroupTable.TABLE_NAME}.${GroupTable.RECIPIENT_ID} 
-      WHERE $where 
+        LEFT OUTER JOIN ${GroupTable.TABLE_NAME} ON $TABLE_NAME.$RECIPIENT_ID = ${GroupTable.TABLE_NAME}.${GroupTable.RECIPIENT_ID}
+        LEFT OUTER JOIN (
+          SELECT group_id, GROUP_CONCAT(${GroupTable.MembershipTable.TABLE_NAME}.${GroupTable.MembershipTable.RECIPIENT_ID}) as ${GroupTable.MEMBER_GROUP_CONCAT} 
+          FROM ${GroupTable.MembershipTable.TABLE_NAME}
+        ) as MembershipAlias ON MembershipAlias.${GroupTable.MembershipTable.GROUP_ID} = ${GroupTable.TABLE_NAME}.${GroupTable.GROUP_ID}
+      WHERE $where
       ORDER BY $orderBy
     """.trimIndent()
 
diff --git a/app/src/main/java/org/thoughtcrime/securesms/database/helpers/SignalDatabaseMigrations.kt b/app/src/main/java/org/thoughtcrime/securesms/database/helpers/SignalDatabaseMigrations.kt
index cdd22f0c6e..acde7cb6db 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/database/helpers/SignalDatabaseMigrations.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/database/helpers/SignalDatabaseMigrations.kt
@@ -27,6 +27,7 @@ import org.thoughtcrime.securesms.database.helpers.migration.V168_SingleMessageT
 import org.thoughtcrime.securesms.database.helpers.migration.V169_EmojiSearchIndexRank
 import org.thoughtcrime.securesms.database.helpers.migration.V170_CallTableMigration
 import org.thoughtcrime.securesms.database.helpers.migration.V171_ThreadForeignKeyFix
+import org.thoughtcrime.securesms.database.helpers.migration.V172_GroupMembershipMigration
 
 /**
  * Contains all of the database migrations for [SignalDatabase]. Broken into a separate file for cleanliness.
@@ -35,7 +36,7 @@ object SignalDatabaseMigrations {
 
   val TAG: String = Log.tag(SignalDatabaseMigrations.javaClass)
 
-  const val DATABASE_VERSION = 171
+  const val DATABASE_VERSION = 172
 
   @JvmStatic
   fun migrate(context: Application, db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
@@ -130,6 +131,10 @@ object SignalDatabaseMigrations {
     if (oldVersion < 171) {
       V171_ThreadForeignKeyFix.migrate(context, db, oldVersion, newVersion)
     }
+
+    if (oldVersion < 172) {
+      V172_GroupMembershipMigration.migrate(context, db, oldVersion, newVersion)
+    }
   }
 
   @JvmStatic
diff --git a/app/src/main/java/org/thoughtcrime/securesms/database/helpers/migration/V172_GroupMembershipMigration.kt b/app/src/main/java/org/thoughtcrime/securesms/database/helpers/migration/V172_GroupMembershipMigration.kt
new file mode 100644
index 0000000000..659fb7b84d
--- /dev/null
+++ b/app/src/main/java/org/thoughtcrime/securesms/database/helpers/migration/V172_GroupMembershipMigration.kt
@@ -0,0 +1,65 @@
+package org.thoughtcrime.securesms.database.helpers.migration
+
+import android.app.Application
+import androidx.core.content.contentValuesOf
+import net.zetetic.database.sqlcipher.SQLiteDatabase
+import org.signal.core.util.SqlUtil
+import org.signal.core.util.readToList
+import org.signal.core.util.requireNonNullString
+
+/**
+ * Migrates all IDs from the GroupTable into the GroupMembershipTable
+ */
+@Suppress("ClassName")
+object V172_GroupMembershipMigration : SignalDatabaseMigration {
+  override fun migrate(context: Application, db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
+    db.execSQL(
+      """
+      CREATE TABLE group_membership (
+        _id INTEGER PRIMARY KEY,
+        group_id TEXT NOT NULL,
+        recipient_id INTEGER NOT NULL,
+        UNIQUE(group_id, recipient_id)
+      );
+      """.trimIndent()
+    )
+
+    //language=sql
+    val total = db.query("SELECT COUNT(*) FROM groups").use {
+      if (it.moveToFirst()) {
+        it.getInt(0)
+      } else {
+        0
+      }
+    }
+
+    (0..total).chunked(500).forEachIndexed { index, _ ->
+      //language=sql
+      val groupIdToMembers: List<Pair<String, List<Long>>> = db.query("SELECT members, group_id FROM groups LIMIT 500 OFFSET ${index * 500}").readToList { cursor ->
+        val groupId = cursor.requireNonNullString("group_id")
+        val members: List<Long> = cursor.requireNonNullString("members").split(",").filterNot { it.isEmpty() }.map { it.toLong() }
+
+        groupId to members
+      }
+
+      for ((group_id, members) in groupIdToMembers) {
+        val queries = SqlUtil.buildBulkInsert(
+          "group_membership",
+          arrayOf("group_id", "recipient_id"),
+          members.map {
+            contentValuesOf(
+              "group_id" to group_id,
+              "recipient_id" to it
+            )
+          }
+        )
+
+        for (query in queries) {
+          db.execSQL(query.where, query.whereArgs)
+        }
+      }
+    }
+
+    db.execSQL("ALTER TABLE groups DROP COLUMN members")
+  }
+}
diff --git a/app/src/main/java/org/thoughtcrime/securesms/jobs/MmsDownloadJob.java b/app/src/main/java/org/thoughtcrime/securesms/jobs/MmsDownloadJob.java
index bf3a92e9d4..b5c4a8b3ad 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/jobs/MmsDownloadJob.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/jobs/MmsDownloadJob.java
@@ -245,7 +245,7 @@ public class MmsDownloadJob extends BaseJob {
     }
 
     if (members.size() > 2) {
-      List<RecipientId> recipients = new ArrayList<>(members);
+      Set<RecipientId> recipients = new HashSet<>(members);
       group = Optional.of(SignalDatabase.groups().getOrCreateMmsGroupForMembers(recipients));
     }
     IncomingMediaMessage   message      = new IncomingMediaMessage(from, group, body, TimeUnit.SECONDS.toMillis(retrieved.getDate()), -1, System.currentTimeMillis(), attachments, subscriptionId, 0, false, false, false, Optional.of(sharedContacts), false, false);
diff --git a/app/src/spinner/java/org/thoughtcrime/securesms/database/GV2Transformer.kt b/app/src/spinner/java/org/thoughtcrime/securesms/database/GV2Transformer.kt
index af1e35d191..2b95054051 100644
--- a/app/src/spinner/java/org/thoughtcrime/securesms/database/GV2Transformer.kt
+++ b/app/src/spinner/java/org/thoughtcrime/securesms/database/GV2Transformer.kt
@@ -3,7 +3,6 @@ package org.thoughtcrime.securesms.database
 import android.database.Cursor
 import com.google.protobuf.ByteString
 import org.signal.core.util.requireBlob
-import org.signal.core.util.requireString
 import org.signal.spinner.ColumnTransformer
 import org.signal.storageservice.protos.groups.local.DecryptedBannedMember
 import org.signal.storageservice.protos.groups.local.DecryptedGroup
@@ -14,7 +13,7 @@ import org.whispersystems.signalservice.api.util.UuidUtil
 
 object GV2Transformer : ColumnTransformer {
   override fun matches(tableName: String?, columnName: String): Boolean {
-    return columnName == GroupTable.V2_DECRYPTED_GROUP || columnName == GroupTable.MEMBERS
+    return columnName == GroupTable.V2_DECRYPTED_GROUP
   }
 
   override fun transform(tableName: String?, columnName: String, cursor: Cursor): String {
@@ -23,8 +22,7 @@ object GV2Transformer : ColumnTransformer {
       val group = DecryptedGroup.parseFrom(groupBytes)
       group.formatAsHtml()
     } else {
-      val members = cursor.requireString(GroupTable.MEMBERS)
-      members?.split(',')?.chunked(20)?.joinToString("<br>") { it.joinToString(",") } ?: ""
+      ""
     }
   }
 }