Incompatible changes in ArangoDB 3.9
It is recommended to check the following list of incompatible changes before upgrading to ArangoDB 3.9, and adjust any client programs if necessary.
The following incompatible changes have been made in ArangoDB 3.9:
The minimum architecture requirements have been raised from the Westmere architecture to the Sandy Bridge architecture. 256 bit AVX instructions are now expected to be present on all targets that run ArangoDB 3.9 executables. If a target does not support AVX instructions, it may fail with SIGILL at runtime.
Disallowed usage of collection names in AQL expressions
The startup option
--query.allow-collections-in-expressions added in 3.8.0
controls whether collection names are allowed in arbitrary places in AQL
expressions. The default was true, but is now changed to false in 3.9.0 to
make queries like
FOR doc IN collection RETURN collection fail, where it was
probably intended to
RETURN doc instead. Also see
ArangoDB Server Query Options
Such unintentional usage of collection names in queries now makes the query fail with error 1568 (“collection used as expression operand”) by default. The option can be set to true to restore the 3.8 behavior. However, the option is deprecated from 3.9.0 on and will be removed in future versions. From then on, unintended usage of collection names will always be disallowed.
If you use queries like
RETURN collection then you should replace them with
FOR doc IN collection RETURN doc to ensure future compatibility.
“Old” system collections
--database.old-system-collections was introduced in 3.6 and 3.7
to control if the obsolete system collections
be created with every new database or not.
The option was introduced with a default value of
true in 3.6 and 3.7 for
downwards-compatibility reasons. With the introduction of the option, it was
also announced that the default value would change to
false in ArangoDB 3.8.
This has happened, meaning that 3.8 installations by default will not create
these system collections anymore.
In ArangoDB 3.9 the option
--database.old-system-collections is now
completely obsolete, and ArangoDB will never create these system collections
for any new databases. The option can still be specified at startup, but it
Replaced arangovpack options
The former options
--pretty of the arangovpack utility
have been removed and have been replaced with separate options for specifying
the input and output types:
The former option
--print-non-json has been replaced with the new option
--fail-on-non-json which makes arangovpack fail when trying to emit non-JSON
types to JSON output.
Export API removed
The REST API endpoint
/_api/export has been removed in ArangoDB 3.9.
This endpoint was previously only present in single server, but never
supported in cluster deployments.
The purpose of the endpoint was to provide the full data of a collection without holding collection locks for a long time, which was useful for the MMFile storage engine with its collection-level locks.
The MMFiles engine is gone since ArangoDB 3.7, and the only remaining
storage engine since then is RocksDB. For the RocksDB engine, the
/_api/export endpoint internally used a streaming AQL query such as
FOR doc IN @@collection RETURN doc
anyway. To remove API redundancy, the API endpoint has been deprecated in ArangoDB 3.8 and is now removed. If the functionality is still required by client applications, running a streaming AQL query can be used as a substitution.
The default value of arangodump’s
--envelope option changes from
in 3.8 to
false in 3.9. This change turns on the non-envelope dump
format by default, which will lead to smaller and slightly faster dumps.
In addition, the non-enveloped format allows higher parallelism when
restoring dumps with arangorestore.
The non-enveloped dump format is different to the enveloped dump format used by default in previous versions of ArangoDB.
In the enveloped format, dumps were JSONL files with a JSON object in each
line, and the actual database documents were placed inside a
There was also a
type attribute for each line, which designated
the type of object in that line (typically this will have been type
meaning “document”). The old, enveloped format looks like this:
The non-enveloped format which is now enabled by default only contains the actual documents, e.g.
The change of the default dump format may have an effect on third-party
backup tools or script. arangorestore will work fine with both formats.
To switch between the formats, arangodump provides the
With the default dump format changing from the enveloped variant to the non-enveloped variant, arangorestore will now by default be able to employ higher parallelism when restoring data of large collections.
When restoring a collection from a non-enveloped dump, arangorestore can
send multiple batches of data for the collection in parallel if it can read
the dump files faster than the server can respond to arangorestore’s requests.
This increased parallelism normally helps to speed up the restore process,
but it can also lead to arangorestore saturating the server with its restore
In this case it is advised to decrease the value of arangorestore’s
option accordingly. The value of
--threads will the determine the maximum
parallelism used by arangorestore.