perf(database): index the message key for chat and message-id lookups

prisma/postgresql-migrations/20261028200000_add_message_key_indexes/migration.sql

@@ -0,0 +1,29 @@
+-- Index the message key (issue #2753).
+--
+-- "Message" had only its primary key and "instanceId", so every lookup by chat or by message id
+-- read all messages of the instance. The key is filtered in two forms, and PostgreSQL uses an
+-- expression index only for the same expression:
+--   * Prisma JSON path filters (key: { path: ['remoteJid'], equals }) compile to "key" #> '{remoteJid}'.
+--   * Raw queries (getMessage, messages.update, the read and unread updates, fetchChats and the
+--     Chatwoot service) use "key"->>'id' and "key"->>'remoteJid'.
+-- Prisma cannot declare expression indexes in the schema, so they live in this migration.
+--
+-- CONCURRENTLY keeps writes to "Message" going while each index builds. prisma migrate deploy runs
+-- the statements of this file one by one, outside a transaction, so CONCURRENTLY is allowed here.
+-- If a build fails part-way, PostgreSQL leaves an INVALID index under that name: drop it
+-- (DROP INDEX CONCURRENTLY "<name>"), mark the migration rolled back and deploy again.
+
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "Message_instanceId_keyId_idx" ON "Message"("instanceId", ("key" ->> 'id'));
+
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "Message_instanceId_keyRemoteJid_idx" ON "Message"("instanceId", ("key" ->> 'remoteJid'));
+
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "Message_instanceId_keyIdPath_idx" ON "Message"("instanceId", ("key" #> '{id}'));
+
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "Message_instanceId_keyRemoteJidPath_idx" ON "Message"("instanceId", ("key" #> '{remoteJid}'));
+
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "Message_instanceId_keyRemoteJidAltPath_idx" ON "Message"("instanceId", ("key" #> '{remoteJidAlt}'));

prisma/postgresql-schema.prisma

@@ -179,6 +179,8 @@ model Message {
   session   IntegrationSession? @relation(fields: [sessionId], references: [id])
 
   @@index([instanceId])
+  // Expression indexes on "key" (id, remoteJid, remoteJidAlt) are created in migration
+  // 20261028200000_add_message_key_indexes: Prisma cannot declare them here.
 }
 
 model MessageUpdate {

prisma/psql_bouncer-schema.prisma

@@ -178,6 +178,8 @@ model Message {
   session   IntegrationSession? @relation(fields: [sessionId], references: [id])
 
   @@index([instanceId])
+  // Expression indexes on "key" (id, remoteJid, remoteJidAlt) are created in migration
+  // 20261028200000_add_message_key_indexes: Prisma cannot declare them here.
 }
 
 model MessageUpdate {