Incompatible changes in ArangoDB 3.3

It is recommended to check the following list of incompatible changes before upgrading to ArangoDB 3.3, and adjust any client programs if necessary.

The following incompatible changes have been made in ArangoDB 3.3:

• AQL: during a traversal if a vertex is not found, arangod will not log an error and continue with a NULL value, but will instead register a warning at the query and continue with a NULL value.

  If a non-existing vertex is referenced from a traversal, it is not desirable to log errors as ArangoDB can store edges pointing to non-existing vertices (which is perfectly valid if the low-level insert APIs are used). As linking to non-existing vertices may indicate an issue in/with the data model or the client application, the warning is registered in the query so client applications have access to it.

• ArangoDB usernames must not start with the string :role:.

• The startup configuration parameter --cluster.my-id does not have any effect in 3.3. For compatibility reasons, ArangoDB 3.3 will not fail on startup if the option is still used in the configuration, but it will silently ignore this option.

• The startup configuration parameter --cluster.my-local-info is deprecated now. Using it will make arangod log a warning on startup.

• Server startup: the recommended value for the Linux kernel setting in /proc/sys/vm/max_map_count was increased to a value eight times as high as in 3.2. arangod compares at startup if the effective value of this setting is presumably too low, and it will issue a warning in this case, recommending to increase the value.

  This is now more likely to happen than in previous versions, as the recommended value is now eight times higher than in 3.2. The startup warnings will look like this (with actual numbers varying):

  WARNING {memory} maximum number of memory mappings per process is 65530, which seems too low. it is recommended to set it to at least 512000
  

  Please refer to the Linux kernel documentation for more information on this setting. This change only affects the Linux version of ArangoDB.

Client tools

• The option --recycle-ids has been removed from the arangorestore command. Using this option could have led to problems on the restore, with potential id conflicts between the originating server (the source dump server) and the target server (the restore server).

• The option --compat has been removed from the arangodump command and the /_api/replication/dump REST API endpoint. In order to create a dump from an ArangoDB 2.8 instance, please use an older version of the client tools. Older ArangoDB versions are no longer be supported by the arangodump and arangorestore binaries shipped with 3.3.

Miscellaneous

The minimum supported compiler for compiling ArangoDB from source is now g++ 5.4 (bumped up from g++ 4.9). This change only affects users that compile ArangoDB on their own.