Add note about transactions

Author: simon-dew

modules/n1ql/pages/n1ql-language-reference/insert.adoc

@@ -411,12 +411,11 @@ curl -v -X POST http://localhost:8093/admin/settings -u Administrator:password \
 ----
 endif::flag-devex-rest-api[]
 
-* Use
+* When inserting multiple documents, use
 ifdef::flag-devex-rest-api[]
 the {max-parallelism-srv}[max-parallelism] service-level setting, or
 endif::flag-devex-rest-api[]
-the {max_parallelism_req}[max_parallelism] request-level parameter
-when inserting multiple documents.
+the {max_parallelism_req}[max_parallelism] request-level parameter.
 * When performing bulk inserts, use prepared statements or multiple values.
 * When new documents are inserted, the indexes are updated.
 When a large number of documents are inserted, this may affect the performance of the cluster.

modules/n1ql/pages/n1ql-language-reference/transactions.adoc

@@ -155,6 +155,12 @@ These are explained in the sections below.
 Note that some Couchbase SDKs provide APIs to support Couchbase transactions.
 For further details, refer to {transactions}[Transactions] in the Server documentation.
 
+ifndef::flag-devex-rest-api[]
+[NOTE]
+Couchbase Transactions are not supported via the Data API (Query Service passthrough).
+The Query Service requires that the whole transaction must be executed by a single node, and there is currently no way for the Data API to enforce this.
+endif::flag-devex-rest-api[]
+
 === Couchbase Transactions with the Query Tab
 
 * To execute a transaction containing multiple statements, compose the sequence of statements in the Query editor.