diff --git a/src/main/resources/application.yaml b/src/main/resources/application.yaml
index 56f6adbe..b6db015a 100644
--- a/src/main/resources/application.yaml
+++ b/src/main/resources/application.yaml
@@ -54,13 +54,19 @@ network-store-server:
   preloading-strategy: COLLECTION
   base-uri: http://localhost:8080/
 
-# this structure is shared among all microservices, if you change it, change it everywhere
-# customQuery allows a microservice to set query parameters specific to itself
-# if customQuery is empty, set queryBegin to "?", otherwise set it to "&"
+# this structure is shared among all microservices, if you change it, change it everywhere.
+# customQuery allows a microservice to set query parameters specific to itself.
+# if customQuery is empty, set queryBegin to "?", otherwise set it to "&".
 # this allow the user to add additional query elements common to all microservices
-# and using the appropriate leading character depending on whether the microsevice
-# uses custom query parameters
+# and to use the appropriate leading character depending on whether the microsevice
+# uses custom query parameters or not. customQueryBegin in this file must always be '?',
+# it is present only to be able to be overriden by deployments in the
+# manyschemas mode. It is used only for microservices that have predefined
+# query parameters, and it must be used if customQuery is not empty, otherwise
+# the manyschema mode doesn't work, so define it everywhere because it doesn't
+# hurt.
 queryBegin: '?'
+customQueryBegin: '?'
 customQuery:
 dbName: dynamicmappings
 dbApi: jdbc
diff --git a/src/main/resources/database.properties b/src/main/resources/database.properties
index f8880c13..a7da048d 100644
--- a/src/main/resources/database.properties
+++ b/src/main/resources/database.properties
@@ -7,6 +7,10 @@
 dbVendor=postgresql
 host=localhost
 port=5432
+# use this to set common query parameters, and use the predefined
+# '${queryBegin}' marker to put the correct leading char '?' or '&' depending
+# on whether the microservice has predefined query parameters.
+# for example, use this (with the ${} and all): query=${queryBegin}timeout=5&reconnect=true
 query=
 login=postgres
 password=postgres
@@ -29,5 +33,5 @@ dbUrlManySchemas=${dbProtocolHost}${dbManySchemasPath}
 # leave this if you want 1 database per microservice
 dbUrl=${dbUrlManyBases}
 # use this if you want 1 database for all microservice, each in a schema
-# and set commonDbName
+# and set commonDbName in database.properties, and set queryBegin: '&' and customQueryBegin: '&' in application.yaml
 #dbUrl=${dbUrlManySchemas}