PL/SQL INSERT INTO & Partitions - oracle

I would like to start with saying that I am still learning PL/SQL. I was wondering if you could share your opinion on the following topic/questions. Basically, I want to insert data from Table X into Table Y via a package. I have already read about the inserting part, so this is clear, however I was wondering what will happen with existing partitions. Lets say that Table Y has partitions. What will happen when we insert new data from Table X? Will it be divided into the partitions or not? Or what if i have interval partitions, will they grow based on the incomming data from Table X? Do I need to “trigger”/ call the partitions inside the package?
Thank you in advance for your help! I am just looking for tips and advises so that I can figure out how to setup my tables and the package (in case i need to call the partitions there). Like for example should I have interval partitions or not.
Thank you for your time!

If the data you're inserting fits the definition of the existing partitions then the new data will be added to the existing partitions. If the new data does not fit the definition of any existing partition, then either
a new partition will be created for the new data, if the table is set up to do so, or
the insert will fail and you will have to manually create a new partition capable of holding the new data.
Which of the above situations will happen in your case depends entirely on how your table was created, on what partitions already exist, on what the partitioning method and key is/are, and on the data you're trying to insert.
You don't have to "do" anything in your code to tell it which partition to use. A partitioned table behaves no differently than a non-partitioned table.
Best of luck.

Related

Move Range Interval partition data from one table to history table in other database

We have a primary table that is Range partitioned by date with a 1-month interval. It's also a list sub-partitioned with 4 distinct values. So essentially it is one month partition having 4 sub-partitions.
Database: Oracle 19c
I need advice on how to effectively move the partition/sub-partition data from active schema to historical schema in another database.
Also, there are about 30 tables that are referenced partitioned on the primary table for which the data needs to be moved as well. Overall I'm looking to move about 2500 subpartitions
I'm not sure if an exchange partition would be the right approach in this scenario?
TIA
You could use exchange to get the data rapidly out of your active table, but you would still then to send that table over the wire to the remote history database to load it in.
In which case, using "exchange" probably is just adding more steps to the process for little gain. (There are still potential uses here depending on how you want to handle indexing etc).
But simplest is perhaps just transferring the data over, assuming a common structure between the two tables, ie
insert /*+ APPEND */ into history_table#remote_db
select * from active_table partition ( myparname )
I can't remember if partition naming syntax is supported over a db link, but if not, then the appropriate date predicates will do the same trick, and then just follow up with:
alter table active_table truncate partition myparname;

How to add new partitions automatically in partitioned table based on data inserted in GreenPlum.?

I have a partitioned table in greenplum(modeled after psql), which has been partitioned with specific range of values.
Now, i have to insert the data again into the same table. New values for Partitions might overlap with existing ones. I have created alter command with new start and end dates. But, if the overlaps are there, the command fails. So, i need to create partition for each date, in order to avoid whole command failure.
Just wondering, if there is a way in greenplum to create partitions based on the inserted data automatically, just like hive does.
thanks for your help.
Greenplum does not (currently) create additional partitions for data which does not fit into an existing partition.
If you have a default partition on the table it will receive all the records which do not fit into one of the specified partitions. You can then use ALTER TABLE ... SPLIT DEFAULT PARTITION (see the documentation if required) to create the new partitions for any new dates at the end of the load batch.

Hadoop & Hive as warehouse: daily data deliveries

I am evaluating the combination of hadoop & hive (& impala) as a repolacement for a large data warehouse. I already set up a version and performance is great in read access.
Can somebody give me any hint what concept should be used for daily data deliveries to a table?
I have a table in hive based on a file I put into hdfs. But now I have on a daily basis new transactional data coming in.
How do I add them ti the table in hive.
Inserts are not possible. HDFS cannot append. So whats the gernal concept I need to follow.
Any advice or direction to documentation is appreciated.
Best regards!
Hive allows for data to be appended to a table - the underlying implementation of how this happens in HDFS doesn't matter. There are a number of things you can do append data:
INSERT - You can just append rows to an existing table.
INSERT OVERWRITE - If you have to process data, you can perform an INSERT OVERWRITE to re-write a table or partition.
LOAD DATA - You can use this to bulk insert data into a table and, optionally, use the OVERWRITE keyword to wipe out any existing data.
Partition your data.
Load data into a new table and swap the partition in
Partitioning is great if you know you're going to be performing date based searches and gives you the ability to use options 1, 2, & 3 at either the table or partition level.
Inserts are not possible
Inserts are possible ,like you can create a new table and insert the data from new table to old table.
But simple solution is You can load data of the file into Hive table with the below command.
load data inpath '/filepath' [overwrite] into table tablename;
If you use overwrite then only existing data replced with new data otherwise It is appending only.
You can even schedule the script by creating a shell script.

how to get change global_stats for a particular partition to YES

i have sql table which has partitions.
I recently created one partition. Even if i enter data to satisfy that partition , my no of records for this partition remains null. Its not getting increased.
the only difference i found in the existing and newly creating partitions is GLOBAL_STATS(in table All_tab_partitions) is YES for all, except the one i have created now.
Please guide me in this.
Oracle doesn't recompute statistis automatically for every row inserted. You can analyze the partition manualy. There is also no relation to global_stats.

Can't drop Oracle index partition -- any alternative besides dropping entire index and rebuilding?

So, I have a .NET program doing batch loading of records into partitioned tables using array bound stored procedure calls via Oracle ODP.NET, but that's neither here nor there.
What I would like to know is: because I have a partitioned index on said tables, the speed of the batch load is pretty slow. I fully understand that I cannot drop an index partition, but I would obviously prefer not to have to drop and rebuild the entire index since that will take considerably more time to execute. Is this my only recourse?
Is there a fairly simple way to drop the partition itself and then rebuild the partition and index partition that would save time and go about accomplishing my goal?
Are you loading an entire partition at once? Or are you merely adding new rows to an existing partition? Are all the indexes equipartitioned with the table?
Normally, if you are loading data into a partitioned table, your partitioning scheme is chosen so that each load will put data into a fresh partition. If that is the case, you can use partition exchange to load the data. In a nutshell, you load data into an (unindexed) staging table whose structure matches the real table, you create the indexes to match the indexes on the real table, and then do
ALTER TABLE partitioned_table
EXCHANGE PARTITION new_partition_name
WITH TABLE staging_table_name
WITHOUT VALIDATION;

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