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- What are the pros and cons of the Apache Parquet format compared to . . .
"Overall, Parquet showed either similar or better results on every test [than Avro] The query-performance differences on the larger datasets in Parquet’s favor are partly due to the compression results; when querying the wide dataset, Spark had to read 3 5x less data for Parquet than Avro
- Reading Fixing a corrupt parquet file - Stack Overflow
Either the file is corrupted or this is not a parquet file when I tried to construct a ParquetFile instance I assume appending PAR1 to the end of the file could help this? But before that, I realized that the ParquetFile constructor optionally takes an "external" FileMetaData instance, which has properties that I may be able to estimate (?)
- Inspect Parquet from command line - Stack Overflow
parquet-avro: Could not resolve dependencies for project org apache parquet:parquet-avro:jar:1 15 0-SNAPSHOT: org apache parquet:parquet-hadoop:jar: tests:1 15 0-SNAPSHOT was not found in https: jitpack io during a previous attempt This failure was cached in the local repository and resolution is not reattempted until the update interval of
- How to view Apache Parquet file in Windows? - Stack Overflow
Apache Parquet is a binary file format that stores data in a columnar fashion Data inside a Parquet file is similar to an RDBMS style table where you have columns and rows But instead of accessing the data one row at a time, you typically access it one column at a time Apache Parquet is one of the modern big data storage formats
- Is it possible to read parquet files in chunks? - Stack Overflow
If your parquet file was not created with row groups, the read_row_group method doesn't seem to work (there is only one group!) However if your parquet file is partitioned as a directory of parquet files you can use the fastparquet engine, which only works on individual files, to read files then, concatenate the files in pandas or get the
- Spark parquet partitioning : Large number of files
First I would really avoid using coalesce, as this is often pushed up further in the chain of transformation and may destroy the parallelism of your job (I asked about this issue here : Coalesce reduces parallelism of entire stage (spark))
- Extension of Apache parquet files, is it . pqt or . parquet?
I wonder if there is a consensus regarding the extension of parquet files I have seen a shorter pqt extension, which has typical 3-letters (like in csv, tsv, txt, etc) and then there is a rather long (therefore unconventional(?)) parquet extension which is widely used
- Unable to infer schema when loading Parquet file
By default the spark parquet source is using "partition inferring" which means it requires the file path to be partition in Key=Value pairs and the loads happens at the root To avoid this, if we assure all the leaf files have identical schema, then we can use df = spark read format("parquet")\ option("recursiveFileLookup", "true")
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