I want to copy a partitioned table in bigquery along with the partion times of each row. Is it possible to do this. The schema of source and destination table should be the same
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I have an external hive table, partitioned on the date column. Each date has multiple AB test experiment’s data.
I need to create a job that drops experiments which have ended more than 6 months ago.
Since dropping data in an external hive partitioned table, drops the entire partition. In this case, data for one whole date. Is there a way to only drop part of a date?
I have a partitioned table Student which already has one partition column dept. I need to add new partition column gender
Will it be possible to add this new partition column in already partitioned hive table.
The table data does not have gender column. It is a new constant column to be added in hive table.
Partitions are hierarchical folders like table_location/dept=Accounting/gender=male/
Folder structure should exist. You can easily add non-partition column as the last one and it will return NULLs if the data does not contain that column, but to add a partition column the easiest way is to create new table partitioned as you want, insert overwrite that table from the old one (selecting partitions columns as the last ones), drop old table, rename new one.
See this answer about dynamic partitions load: https://stackoverflow.com/a/48901871/2700344
Hi my table has 150 columns and i dont want to mention the column name while doing partition. Is there any way using temp table to create partitioned table from non partitioned one.
Temporary table in Hive doesn't support Partitioning.
You cannot create any permanent partitioned table without mentioning Partition
Column.
We can create a partition on BigQuery table while creating a BigQuery table.
I have some questions on the partition.
How to append data to an existing partition in the BigQuery table.
How to create a new Partition in an existing BigQuery table if there is already partition present in that BiQuery table.
How to do truncate and load data to a partition in the BigQuery table(overwrite data in a partition in the BigQuery table).
How to append data to an existing partition in the BigQuery table.
Either you do this from Web UI or with API or with any client of your choice - the approach is the same - you just set your Destination Table with respective partition decorator, like below as an example
yourProject.yourDataset.youTable$20171010
Please note: to append your data - you need to use Append to table for Write Preference
How to create a new Partition in an existing BigQuery table if there is already partition present in that BiQuery table.
If the partition you set in decorator of destination table does not exist yet - it will be added for you
How to do truncate and load data to a partition in the BigQuery table(overwrite data in a partition in the BigQuery table).
To truncate and load to a specific partition - you should use Overwrite table for Write Preference
How to apply Partition on hive table which is already partitioned. I am not able to fetch the partitioned data into the folder after the data is loaded.
1st rule of partitioning in hive is that the partitionioning column should be the last column in the data. since the data is already partitioned lets say we are partitioning data on gender M/F there will be two directories gender=M and gender=F be created inside each of the directories respective gender data will be available and last column again in this data will be gender.
If you want to partiton data again on partitioned table use insert into select and make sure last column you use is the partition column you want to on the partitioned data.
Did you add a partition manually with the Hdfs command ? In that case metastore will not keep track of partitions being added unless you specify " alter table add partition "...
try this
MSCK REPAIR TABLE table_name;
If that is not the case , then try to drop partitions and create the partitions again . Use alter table command to do this. but you will lose the data . and your partitioning column value should be mentioned as last column in case if you are doing a dynamic partition insert.