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jmhsieh
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Jan 20, 2026
docs/geneva/udfs/index.mdx
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| `checkpoint_size` controls how many rows are processed before checkpointing, and therefore reporting and saving progress. | ||
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| In LanceDB, the default number of rows per fragment is 1024 * 1024 rows. Conside a captioning UDF that takes 30s per row. It could take a year (!) before any results show up! (e.g. 30s/row * 1024*1024 rows/fragment => 30M s/fragment => 8.3k hours/fragment -> 347 days/fragment). To enable these to be parallelized, we provide a `batch_size` setting so the work can be split between workers and so that that partial results are checkpointed more frequently to enable finer-grained progress and job recovery. | ||
| By default, Geneva uses adaptive checkpoint sizing, so you don't need to set this parameter. This is because UDFs can be quite varied -- some can be simple operations where thousands of calls can be completed per second, while others may be slow and require 30s per row. So a simple default like "write every 1000 rows" might write once a second or once every 8 hours! Geneva will avoid this by adapting its checkpointing rate to your task. But if you want to see writes more or less frequently, you can set `checkpoint_size` manually. |
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I've been having some issues with this feature, we might want to mark the adaptive checkpoitn sizing as experiemental for now.
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Adds docs from geneva internal docs about error handling. These looked pretty good already; I only tweaked a couple things to make them sound a little bit less AI, and adjusted the hierarchy to make it clear that there are 3 levels of complexity you can use to customize your error handling.
Touched up the main UDF page too.