[SPARK-23355][SQL][DOC][FOLLOWUP] Add migration doc for TBLPROPERTIES #21269
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cloud-fan
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May 8, 2018
docs/sql-programming-guide.md
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| - Since Spark 2.4, creating a managed table with nonempty location is not allowed. An exception is thrown when attempting to create a managed table with nonempty location. To set `true` to `spark.sql.allowCreatingManagedTableUsingNonemptyLocation` restores the previous behavior. This option will be removed in Spark 3.0. | ||
| - Since Spark 2.4, the type coercion rules can automatically promote the argument types of the variadic SQL functions (e.g., IN/COALESCE) to the widest common type, no matter how the input arguments order. In prior Spark versions, the promotion could fail in some specific orders (e.g., TimestampType, IntegerType and StringType) and throw an exception. | ||
| - In version 2.3 and earlier, `to_utc_timestamp` and `from_utc_timestamp` respect the timezone in the input timestamp string, which breaks the assumption that the input timestamp is in a specific timezone. Therefore, these 2 functions can return unexpected results. In version 2.4 and later, this problem has been fixed. `to_utc_timestamp` and `from_utc_timestamp` will return null if the input timestamp string contains timezone. As an example, `from_utc_timestamp('2000-10-10 00:00:00', 'GMT+1')` will return `2000-10-10 01:00:00` in both Spark 2.3 and 2.4. However, `from_utc_timestamp('2000-10-10 00:00:00+00:00', 'GMT+1')`, assuming a local timezone of GMT+8, will return `2000-10-10 09:00:00` in Spark 2.3 but `null` in 2.4. For people who don't care about this problem and want to retain the previous behaivor to keep their query unchanged, you can set `spark.sql.function.rejectTimezoneInString` to false. This option will be removed in Spark 3.0 and should only be used as a temporary workaround. | ||
| - In version 2.3 and earlier, Spark converts Parquet Hive tables by default but ignores table properties like `TBLPROPERTIES (parquet.compression 'NONE')`. This happens for ORC Hive table properties like `TBLPROPERTIES (orc.compress 'NONE')` in case of `spark.sql.hive.convertMetastoreOrc=true`, too. Since Spark 2.4, Spark supports Parquet/ORC specific table properties while converting Parquet/ORC Hive tables. As an example, `CREATE TABLE t(id int) STORED AS PARQUET TBLPROPERTIES (parquet.compression 'NONE')` would generate Snappy parquet files during insertion in Spark 2.3, and in Spark 2.4, the result would be uncompressed parquet files. |
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Spark supports Parquet/ORC specific table properties while converting ..
supports -> respects
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Thanks. It's updated.
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LGTM |
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Test build #90372 has finished for PR 21269 at commit
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Test build #90373 has finished for PR 21269 at commit
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Merged to master. |
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Thank you, @HyukjinKwon and @cloud-fan . |
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What changes were proposed in this pull request?
In Apache Spark 2.4, SPARK-23355 fixes a bug which ignores table properties during convertMetastore for tables created by STORED AS ORC/PARQUET.
For some Parquet tables having table properties like TBLPROPERTIES (parquet.compression 'NONE'), it was ignored by default before Apache Spark 2.4. After upgrading cluster, Spark will write uncompressed file which is different from Apache Spark 2.3 and old.
This PR adds a migration note for that.
How was this patch tested?
N/A