# ES Continuous Transforms Checkpoint not updating **URL:** \ **Category:** Elasticsearch\ **Tags:** transforms\ **Created:** [February 25, 2021, 1:34am UTC](https://discuss.elastic.co/t/es-continuous-transforms-checkpoint-not-updating/265421 "2021-02-25T01:34:36Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![Hendrik\_Muhs](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/hendrik_muhs/32/25802_2.png) [@Hendrik\_Muhs](https://discuss.elastic.co/u/Hendrik_Muhs)\ **Post date:** [March 2, 2021, 2:42pm UTC](https://discuss.elastic.co/t/es-continuous-transforms-checkpoint-not-updating/265421/2 "2021-03-02T14:42:34Z")
For running transform in continuous mode the `sync` section is mandatory. It's basically used to find out what has changed. The idea is to only do the necessary updates but _not_ a full re-run. `sync.time.field` must be a date field that is using a real timestamp. A checkpoint is basically a timestamp until all data has been processed and the next time transform triggers it looks for new data that has arrived _after_ the checkpoint. For the same reason transform will not be able to see new documents with a historic timestamp. If you don't know what to take as field, you can use a ingest pipeline and add an ingest timestamp as described [here](https://discuss.elastic.co/t/dec-12th-2018-en-elasticsearch-automatically-adding-a-timestamp-to-documents/159314). `sync.time.delay` describes how much time transform should reserve for ingest processing and data coming in out of order. For example: Assume the timestamps are created on some IoT device and only send once every minute as batch. Network takes some millisecondes, next you have a queue, than ingest, finally it enters elasticsearch. Note the index refresh interval which adds another second. Delay is basically the sum of the steps I described, with other words, when transform sees the new datapoint, it can be worst case `sum(steps) ms` old. That's your ingest `delay`. There is a trick: If you use the suggested ingest timestamp, you skip a lot of the steps above and your worst case assumption becomes a lot easier. I hope that helps. --- _[View the full topic](https://discuss.elastic.co/t/es-continuous-transforms-checkpoint-not-updating/265421)._