Verify that the MDEX Engine processes the updates according to your configuration in the partial updates pipeline.
The MDEX Engine processes updates on a record-by-record basis. Updates fail or succeed entirely at the record level. This means that a record update that fails (for example, because it attempts to assign an unknown dimension value to the record), leaves the value of the record unchanged. Property value changes or dimension value changes in the failed record update have no effect.
In addition, if an error occurs during a record update, and subsequent update operations relate to the same record, these operations may also fail. However, in general, previous and future record updates and dimension updates are not affected by a specific record update failure.
For example, if a partial update operation fails, because you try to delete a record that does not exist, or add a child dimension value to a dimension that does not exist, the MDEX Engine does all of the following:
Update files that are due for processing are deleted after each
partial update that has successfully processed them. They do not accumulate in
the
dgraph_input/updates directory.
The default directory the MDEX Engine uses for storing failed update
files is
.
<updatedir>/failed_updates/
Note
You can use the
--failedupdatedir flag for the Dgraph to
specify the directory in which the MDEX Engine should store the failed update
files.
Therefore, to troubleshoot failed update operations, provision enough
disk space in your working directory for
/failed_updates, and check this directory for
failed update operations, if you notice any failed update errors in the log.
During development, use the
--updateverbose flag to specify that the MDEX Engine
should output verbose messages while processing updates. Do not use this flag
on production systems, because it negatively impacts partial update
performance.
Keep in mind that when the MDEX Engine starts up, it begins to process
queries and updates in parallel. This means that if there are update files in
the
updates directory at startup time, the MDEX Engine
(after opening its port) begins to process those updates at the same time that
it begins to accept and service queries.
