Fokko commented on PR #829:
URL: https://github.com/apache/iceberg-python/pull/829#issuecomment-2219874876
> Can you talk a bit more about "re-aligning"?
Let me give two examples:
### Out of order
```
table {
1: str foo
2: int bar
}
```
It is fine to write a parquet file to this table with:
```
table {
2: int bar
1: str foo
}
```
When the table is being read, the columns are re-ordered by
`to_requested_schema`.
The same goes for casting:
```
table {
1: str foo
2: long bar
}
```
It is fine to write:
```
```
table {
1: str foo
2: int bar
}
```
The upcasting to a long will be done when the data is being read, but it is
less efficient since we first let Arrow read the data as an int, and then it
will do the cast to long in `to_requested_schema` to be able to append the
files.
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