Edit the key-value metadata of a Parquet file

Modify the file-level key-value metadata of a Parquet file in place, without copying any row-group data. Individual entries can be added, updated or removed.

Usage

edit_parquet_metadata(file, metadata)

Arguments

file

Path to a Parquet file.

metadata

Key-value pairs to add, update or remove. Accepted forms:

• A named character vector – each name is a key and each element is its new value. Set a value to NA to remove that key.

• A data frame with two columns – the first column contains keys and the second contains values. An NA value removes that key.

• NULL – removes all key-value metadata from the file.

Keys that are not mentioned in metadata are left unchanged.

Value

NULL, invisibly. Called for its side effect.

Warning

This function is not atomic! If it is interrupted it may leave the file in a corrupt state. To work around this create a copy of the original file, edit the copy, and then rename the copy to the original.

See also

read_parquet_metadata() to inspect metadata. write_parquet() for the metadata argument when writing. append_parquet() to append rows without copying.

Examples

tmp <- tempfile(fileext = ".parquet")
write_parquet(data.frame(x = 1:5), tmp)

# Add a new entry
edit_parquet_metadata(tmp, c(created_by_user = "Alice"))
read_parquet_metadata(tmp)$file_meta_data$key_value_metadata
#> [[1]]
#> # A data frame: 2 × 2
#>   key             value                                                
#>   <chr>           <chr>                                                
#> 1 ARROW:schema    /////3gAAAAQAAAAAAAKAA4ADAALAAQACgAAABQAAAAAAAABBAAK…
#> 2 created_by_user Alice                                                
#> 

# Update an existing entry
edit_parquet_metadata(tmp, c(created_by_user = "Bob"))
read_parquet_metadata(tmp)$file_meta_data$key_value_metadata
#> [[1]]
#> # A data frame: 2 × 2
#>   key             value                                                
#>   <chr>           <chr>                                                
#> 1 ARROW:schema    /////3gAAAAQAAAAAAAKAA4ADAALAAQACgAAABQAAAAAAAABBAAK…
#> 2 created_by_user Bob                                                  
#> 

# Remove an entry
edit_parquet_metadata(tmp, c(created_by_user = NA_character_))
read_parquet_metadata(tmp)$file_meta_data$key_value_metadata
#> [[1]]
#> # A data frame: 1 × 2
#>   key          value                                                   
#>   <chr>        <chr>                                                   
#> 1 ARROW:schema /////3gAAAAQAAAAAAAKAA4ADAALAAQACgAAABQAAAAAAAABBAAKAAw…
#>