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Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Creating Composite List-Range Partitioned Tables

Creating Composite List-Range Partitioned TablesExample 4-14 shows an accounts table that is list partitioned by region and subpartitioned using range by account balance, and row movement is enabled. Subpartitions for different list partitions could have different ranges specified. To learn how using a subpartition template can simplify the specification of a composite partitioned table, see \" Specifying Subpartition Templates to Describe Composite

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Creating Reference-Partitioned Tables

Creating Reference-Partitioned TablesTo create a reference-partitioned table, you specify a PARTITION BY REFERENCE clause in the CREATE TABLE statement. This clause specifies the name of a referential constraint and this constraint becomes the partitioning referential constraint that is used as the basis for reference partitioning in the table. The referential constraint must be enabled and enforced. As with other partitioned tables,

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Single-Level Partitioning

Single-Level PartitioningA table is defined by specifying one of the following data distribution methodologies, using one or more columns as the partitioning key: Range Partitioning Hash Partitioning List Partitioning For example, consider a table with a column of type NUMBER as the partitioning key and two partitions less_than_five_hundred and less_than_one_thousand. The less_than_one_thousand partition contains rows where

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Creating a Composite Range-List Partitioned Table

Creating a Composite Range-List Partitioned TableExample 4-10 illustrates how range-list partitioning might be used. The example tracks sales data of products by quarters and within each quarter, groups it by specified states. A row is mapped to a partition by checking whether the value of the partitioning column for a row falls within a specific partition range. The row is then mapped to a subpartition within that partition by identifying the subpartition

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Truncating Multiple Partitions

Truncating Multiple PartitionsYou can truncate multiple partitions from a range or list partitioned table with the TRUNCATE PARTITION clause of the ALTER TABLE statement. The corresponding partitions of local indexes are truncated in the operation. Global indexes must be rebuilt unless UPDATE INDEXES is specified.For example, the following SQL statement truncates multiple partitions in the range-partitioned sales table. ALTER

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Exchanging a Hash Partitioned Table with a *-Hash Partition

Exchanging a Hash Partitioned Table with a *-Hash PartitionIn this example, you are exchanging a whole hash partitioned table, with all of its partitions, with the partition of a *-hash partitioned table and all of its hash subpartitions. The following example illustrates this concept for a range-hash partitioned table. First, create a hash partitioned table: CREATE TABLE t1 (i NUMBER, j NUMBER) PARTITION BY HASH(i) (PARTITION p1, PARTITION p2); Populate

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Best Practice 1: Use ARCHIVELOG Mode

Best Practice 1: Use ARCHIVELOG ModeArchived redo logs are crucial for recovery when no data can be lost because they constitute a record of changes to the database. Oracle Database can be run in either of two modes: ARCHIVELOG Oracle Database archives the filled online redo log files before reusing them in the cycle. NOARCHIVELOG Oracle Database does not archive the filled online redo log files before reusing them in the cycle. Running

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Best Practice 6: Plan for NOLOGGING Operations in Your Backup/Recovery Strategy

Extract, Transform, and LoadThe ETL process uses several Oracle features and a combination of methods to load (re-load) data into a data warehouse. These features consist of: Transportable tablespaces Transportable tablespaces allow users to quickly move a tablespace across Oracle Databases. It is the most efficient way to move bulk data between databases. Oracle Database provides the ability to transport tablespaces across

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Concurrent Execution of Union All

Concurrent Execution of Union AllSet operators like UNION or UNION ALL consist of multiple queries (branches) combined to a single SQL statement. Traditionally, set operators are processed in a sequential manner. Individual branches can be processed in serial or parallel, but only one branch at a time, one branch after another. While this approach satisfies many use cases, there are situations where the processing of multiple branches

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Modifying List Partitions: Adding Values

About Modifying List Partitions: Adding ValuesList partitioning enables you to optionally add literal values from the defining value list. This section contains the following topics: Adding Values for a List Partition Adding Values for a List Subpartition

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioning Overview

Partitioning OverviewPartitioning allows a table, index, or index-organized table to be subdivided into smaller pieces, where each piece of such a database object is called a partition. Each partition has its own name, and may optionally have its own storage characteristics. This section contains the following topics: Basics of Partitioning Partitioning Key Partitioned Tables Partitioned Index-Organized Tables System

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Global Nonpartitioned Indexes

Global Nonpartitioned IndexesGlobal nonpartitioned indexes behave just like local nonpartitioned indexes. Figure 2-8 offers a graphical view of global nonpartitioned indexes. Figure 2-8 Global Nonpartitioned Index Description of \"Figure 2-8 Global Nonpartitioned Index\"

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partition Pruning

Partition PruningPartition pruning is an essential performance feature for data warehouses. In partition pruning, the optimizer analyzes FROM and WHERE clauses in SQL statements to eliminate unneeded partitions when building the partition access list. This functionality enables Oracle Database to perform operations only on those partitions that are relevant to the SQL statement. This section contains the following

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Incremental Data Loading in Parallel

Incremental Data Loading in ParallelParallel DML combined with the updatable join views facility provides an efficient solution for refreshing the tables of a data warehouse system. To refresh tables is to update them with the differential data generated from the OLTP production system. In the following example, assume a refresh of a table named customers that has columns c_key, c_name, and c_addr. The differential data contains either

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Creating List-Partitioned Index-Organized Tables

Creating List-Partitioned Index-Organized TablesThe other option for partitioning index-organized tables is to use the list method. In the following example, the sales index-organized table is partitioned by the list method. Example 4-24 uses the example tablespace, which is part of the sample schemas in your seed database. Normally you would specify different tablespace storage for different partitions. Example 4-24 Creating a list-partitioned

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Default Parallelism

Default ParallelismIf the PARALLEL clause is specified but no degree of parallelism is listed, the object gets the default DOP. Default parallelism uses a formula to determine the DOP based on the system configuration, as in the following: For a single instance, DOP = PARALLEL_THREADS_PER_CPU x CPU_COUNT For an Oracle RAC configuration, DOP = PARALLEL_THREADS_PER_CPU x CPU_COUNT x INSTANCE_COUNT By default, INSTANCE_COUNT

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Dropping Partitioned Tables

About Dropping Partitioned TablesOracle Database processes a DROP TABLE statement for a partitioned table in the same way that it processes the statement for a nonpartitioned table. One exception is when you use the PURGE keyword. To avoid running into resource constraints, the DROP TABLE... PURGE statement for a partitioned table drops the table in multiple transactions, where each transaction drops a subset of the partitions or

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Specifying Partitioning When Creating Index-Organized Tables

Specifying Partitioning When Creating Index-Organized TablesFor index-organized tables, you can use the range, list, or hash partitioning method. The semantics for creating partitioned index-organized tables is similar to that for regular tables with these differences: When you create the table, you specify the ORGANIZATION INDEX clause, and INCLUDING and OVERFLOW clauses as necessary. The PARTITION clause can have OVERFLOW subclauses that allow you to specify

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Bigfile Tablespaces

Bigfile TablespacesOracle Database enables the creation of bigfile tablespaces. A bigfile tablespace consists of a single data or temporary file which can be up to 128 TB. The use of bigfile tablespaces can significantly reduce the number of data files for your database. Oracle Database supports parallel RMAN backup and restore on single data files. See Also: Oracle Database Backup and Recovery User's Guide Consequently,

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Merging Partitions and Subpartitions

About Merging Partitions and SubpartitionsUse the ALTER TABLE MERGE PARTITION statement to merge the contents of two partitions into one partition. The two original partitions are dropped, as are any corresponding local indexes. You cannot use this statement for a hash partitioned table or for hash subpartitions of a composite *-hash partitioned table. You cannot merge partitions for a reference-partitioned table. Instead, a merge operation

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Balancing the Workload to Optimize Performance

Balancing the Workload to Optimize PerformanceTo optimize performance, all parallel execution servers should have equal workloads. For SQL statements run in parallel by block range or by parallel execution servers, the workload is dynamically divided among the parallel execution servers. This minimizes workload skewing, which occurs when some parallel execution servers perform significantly more work than the other processes. For the relatively

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Parameters Establishing Resource Limits for Parallel Operations

Parameters Establishing Resource Limits for Parallel OperationsYou can set initialization parameters to determine resource limits. The parameters that establish resource limits are discussed in the following topics: PARALLEL_FORCE_LOCAL PARALLEL_MAX_SERVERS PARALLEL_MIN_PERCENT PARALLEL_MIN_SERVERS PARALLEL_MIN_TIME_THRESHOLD PARALLEL_SERVERS_TARGET SHARED_POOL_SIZE Additional Memory Requirements for Message Buffers Monitor Memory Usage After Processing Begins

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Introduction to Partitioning

Introduction to PartitioningPartitioning addresses key issues in supporting very large tables and indexes by decomposing them into smaller and more manageable pieces called partitions, which are entirely transparent to an application. SQL queries and Data Manipulation Language (DML) statements do not need to be modified to access partitioned tables. However, after partitions are defined, data definition language (DDL) statements

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Parallel DML Operations

About Parallel DML OperationsParallel DML ( PARALLEL INSERT, UPDATE, DELETE, and MERGE ) uses parallel execution mechanisms to speed up or scale up large DML operations against large database tables and indexes. Note: Although DML generally includes queries, in this chapter the term DML refers only to INSERT, UPDATE, MERGE, and DELETE operations. This section discusses the following parallel DML topics: When to Use Parallel DML

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioning of XMLIndex for Binary XML Tables

Partitioning of XMLIndex for Binary XML TablesFor binary XML tables, XMLIndex is equipartitioned with the base table for range, hash, and list partitions. For example: CREATE TABLE purchase_order (id NUMBER, doc XMLTYPE) PARTITION BY RANGE (id) (PARTITION p1 VALUES LESS THAN (10), PARTITION p2 VALUES LESS THAN (MAXVALUE)); CREATE INDEX purchase_order_idx ON purchase_order(doc) INDEXTYPE IS XDB.XMLINDEX LOCAL; See Also: Oracle Database Data Cartridge

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Performance

Deciding Whether to Partition IndexesDue to the selectivity of queries and high concurrency of OLTP applications, the choice of the right index strategy is indisputably an important decisions for the use of partitioning in an OLTP environment. The following basic rules explain the main benefits and trade-offs for the various possible index structures: A nonpartitioned index, while larger than individual partitioned index segments, always

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Splitting a *-Range Subpartition

Splitting a *-Range SubpartitionSplitting a range subpartition of a *-range partitioned table is similar to the description in \" Splitting a Partition of a Range-Partitioned Table \", but the syntax is that of SUBPARTITION rather than PARTITION. For example, the following statement splits a subpartition of the orders table: ALTER TABLE orders SPLIT SUBPARTITION p_pre_may_2007_p_large AT (50000) INTO (SUBPARTITION p_pre_may_2007_med_large

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Summary of Partitioned Index Types

Summary of Partitioned Index TypesTable 3-1 summarizes the types of partitioned indexes that Oracle supports. The key points are: If an index is local, then it is equipartitioned with the underlying table. Otherwise, it is global. A prefixed index is partitioned on a left prefix of the index columns. Otherwise, it is nonprefixed. Table 3-1 Types of Partitioned Indexes Type of Index Index Equipartitioned with Table Index Partitioned

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partition Placement

Partition PlacementPartition placement is not a concern if you stripe across all available devices and distribute the load across all available resources. If you cannot stripe data files across all available devices, then consider partition placement to optimize the use of all available hardware resources (physical disk spindles, disk controllers, and channels to disk). I/O-intensive queries or DML operations should

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Creating a Local Index Across Multiple Tablespaces

Creating a Local Index Across Multiple TablespacesThe following statement is an example of creating a local index on a table where the index segments are spread across tablespaces ts7, ts8, and ts9. CREATE INDEX employee_ix ON employees_range_hash(department_id) LOCAL STORE IN (ts7, ts8, ts9); This local index is equipartitioned with the base table so that it consists of as many partitions as the base table. Each index partition consists of as many

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

When to Use Composite Partitioning

When to Use Composite PartitioningComposite partitioning offers the benefits of partitioning on two dimensions. From a performance perspective you can take advantage of partition pruning on one or two dimensions depending on the SQL statement, and you can take advantage of the use of full or partial partition-wise joins on either dimension. You can take advantage of parallel backup and recovery of a single table. Composite partitioning

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Adding Partitions to a Composite *-Range Partitioned Table

Adding a Partition to a *-Range Partitioned TableAdding a new partition to a [range | list | interval]-range partitioned table is as described previously. The database automatically creates interval partitions for an interval-range partitioned table when data is inserted in a specific interval. You can specify a SUBPARTITION clause for naming and providing ranges for specific subpartitions. If no SUBPARTITION clause is specified, then the partition

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

PARALLEL_MIN_PERCENT

PARALLEL_MIN_PERCENTThis parameter enables users to wait for an acceptable DOP, depending on the application in use. The recommended value for the PARALLEL_MIN_PERCENT parameter is 0 (zero). Setting this parameter to values other than 0 (zero) causes Oracle Database to return an error when the requested DOP cannot be satisfied by the system at a given time. For example, if you set PARALLEL_MIN_PERCENT to 50, which translates

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Granules of Parallelism

Block Range GranulesBlock range granules are the basic unit of most parallel operations, even on partitioned tables. Therefore, from Oracle Database perspective, the degree of parallelism is not related to the number of partitions. Block range granules are ranges of physical blocks from a table. Oracle Database computes the number and the size of the granules during run-time to optimize and balance the work distribution

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Manageability

ManageabilityIn addition to the performance benefits, partitioning also enables the optimal data management for large objects in an OLTP environment. Every partition maintenance operation in Oracle Database can be extended to atomically include global and local index maintenance, enabling the execution of any partition maintenance operation without affecting the 24x7 availability of an OLTP environment. Partition

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Tuning General Parameters for Parallel Execution

Tuning General Parameters for Parallel ExecutionThis section discusses the following topics: Parameters Establishing Resource Limits for Parallel Operations Parameters Affecting Resource Consumption Parameters Related to I/O

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Data Integrity Restrictions

Self-Referential IntegrityDML on tables with self-referential integrity constraints is not parallelized if the referenced keys (primary keys) are involved. For DML on all other columns, parallelism is possible.

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Enabling and Disabling Heat Map

Enabling and Disabling Heat MapYou can enable and disable heat map tracking at the system or session level with the ALTER SYSTEM or ALTER SESSION statement using the HEAT_MAP clause. For example, the following SQL statement enables Heat Map tracking for the database instance. ALTER SYSTEM SET HEAT_MAP = ON; When Heat Map is enabled, all accesses are tracked by the in-memory activity tracking module. Objects in the SYSTEM and SYSAUX

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Splitting Partitions in a *-List Partitioned Table

Splitting Partitions in a *-List Partitioned TablePartitions can be split at both the partition level and at the list subpartition level. Splitting a *-List Partition Splitting a *-List Subpartition

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioned Indexes on Composite Partitions

Partitioned Indexes on Composite PartitionsHere are a few points to remember when using partitioned indexes on composite partitions: Subpartitioned indexes are always local and stored with the table subpartition by default. Tablespaces can be specified at either index or index subpartition levels.

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Example of Table Compression and Partitioning

Example of Table Compression and PartitioningThe following statement moves and compresses an existing partition sales_q1_1998 of table sales: ALTER TABLE sales MOVE PARTITION sales_q1_1998 TABLESPACE ts_arch_q1_1998 COMPRESS; Alternatively, you could choose Hybrid Columnar Compression (HCC), as in the following: ALTER TABLE sales MOVE PARTITION sales_q1_1998 TABLESPACE ts_arch_q1_1998 COMPRESS FOR ARCHIVE LOW; If you use the MOVE statement,

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Step 2: Create Storage Tiers for the Data Classes

Assigning Classes to Storage TiersAfter the storage tiers have been defined, the data classes (partitions) identified in Step 1 can be assigned to the appropriate storage tiers. This provides an easy way to distribute the data across the appropriate storage devices depending on its usage, keeping the data online and available, and stored on the most cost-effective device. In Figure 5-3 data identified to be active, less active, historical,

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioning Restrictions for Multiple Block Sizes

Partitioning Restrictions for Multiple Block SizesUse caution when creating partitioned objects in a database with tablespaces of different block sizes. The storage of partitioned objects in such tablespaces is subject to some restrictions. Specifically, all partitions of the following entities must reside in tablespaces of the same block size: Conventional tables Indexes Primary key index segments of index-organized tables Overflow segments of index-organized

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Merging Range Partitions

Merging Range PartitionsYou are allowed to merge the contents of two adjacent range partitions into one partition. Nonadjacent range partitions cannot be merged. The resulting partition inherits the higher upper bound of the two merged partitions. One reason for merging range partitions is to keep historical data online in larger partitions. For example, you can have daily partitions, with the oldest partition rolled up

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Dynamic Pruning with Nested Loop Joins

Dynamic Pruning with Nested Loop JoinsStatements that are most efficiently executed using a nested loop join use dynamic pruning. For example: SQL> explain plan for select t.time_id, sum(s.amount_sold) from sales s, times t where s.time_id = t.time_id and t.fiscal_year = 2000 and t.fiscal_week_number = 3 group by t.time_id; Explained. SQL> select * from table(dbms_xplan.display); PLAN_TABLE_OUTPUT ----------------------------------------------------------------------------------------------------

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

When to Use Composite List-List Partitioning

When to Use Composite List-List PartitioningComposite list-list partitioning is useful for large tables that are often accessed on different dimensions. You can specifically map rows to partitions on those dimensions based on discrete values. Example 3-12 shows an example of a very frequently accessed current_inventory table. The table is constantly updated with the current inventory in the supermarket supplier's local warehouses. Potentially

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioning for Performance

Partition PruningPartition pruning is the simplest and also the most substantial means to improve performance using partitioning. Partition pruning can often improve query performance by several orders of magnitude. For example, suppose an application contains an Orders table containing a historical record of orders, and that this table has been partitioned by week. A query requesting orders for a single week would

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioning Concepts

2 Partitioning ConceptsPartitioning enhances the performance, manageability, and availability of a wide variety of applications and helps reduce the total cost of ownership for storing large amounts of data. Partitioning allows tables, indexes, and index-organized tables to be subdivided into smaller pieces, enabling these database objects to be managed and accessed at a finer level of granularity. Oracle provides a rich

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Partitioned Materialized Views

Partitioned Materialized ViewsThe underlying storage for a materialized view is a table structure. You can partition materialized views like you can partition tables. When the database rewrites a query to run against materialized views, the query can take advantage of the same performance features from which queries running against tables directly benefit. The rewritten query may eliminate materialized view partitions. If joins

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Impact of a Partition Maintenance Operation on a Partitioned Table with Local Indexes

Impact of a Partition Maintenance Operation on a Partitioned Table with Local IndexesWhen a partition maintenance operation takes place, Oracle Database locks the affected table partitions for any DML operation, except in the case of an ONLINE MOVE. Data in the affected partitions, except a DROP or TRUNCATE operation, is still fully accessible for any SELECT operation. Because local indexes are logically coupled with the table (data) partitions, only the local index partitions of

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Parallel Execution Using Oracle RAC

Limiting the Number of Available InstancesIn Oracle Real Application Clusters, services are used to limit the number of instances that participate in a parallel SQL operation. The default service includes all available instances. You can create any number of services, each consisting of one or more instances. Parallel execution servers are to be used only on instances that are members of the specified service that a given session is connected

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Range Partitioning for Hash Clusters

Range Partitioning for Hash ClustersPartitioned hash clusters are supported in Oracle Database. Only single-level range partitioning is supported for partitioned hash clusters. See Also: Oracle Database SQL Language Reference for information about partitioned hash clusters.

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Dropping Values from a List Subpartition

Dropping Values from a List SubpartitionThis operation is essentially the same as described for \" About Modifying List Partitions: Dropping Values \", however, you use a MODIFY SUBPARTITION clause instead of the MODIFY PARTITION clause. For example, to remove a set of literal values in the value list for subpartition q1_1999_southeast, use the following statement: ALTER TABLE quarterly_regional_sales MODIFY SUBPARTITION q1_1999_southeast

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Rollback Segments

Rollback SegmentsIf you use rollback segments instead of Automatic Undo Management, there are some restrictions when using parallel DML. See Oracle Database SQL Language Reference for information about restrictions for parallel DML and rollback segments.

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Splitting into Multiple Partitions

Splitting into Multiple PartitionsYou can redistribute the contents of one partition or subpartition into multiple partitions or subpartitions with the SPLIT PARTITION and SPLIT SUBPARTITION clauses of the ALTER TABLE statement. When splitting multiple partitions, the segment associated with the current partition is discarded. Each new partitions obtains a new segment and inherits all unspecified physical attributes from the current

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Truncating a Partition with the Cascade Option

Truncating a Partition with the Cascade OptionYou can use cascade truncate operations to a reference partitioned child table with the CASCADE option of TRUNCATE TABLE, ALTER TABLE TRUNCATE PARTITION, and ALTER TABLE TRUNCATE SUBPARTITION SQL statements. When the CASCADE option is specified for TRUNCATE TABLE, the truncate table operation also truncates child tables that reference the targeted table through an enabled referential constraint that

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Dropping Table Partitions

Dropping Table PartitionsUse one of the following statements to drop a table partition or subpartition: ALTER TABLE DROP PARTITION to drop a table partition ALTER TABLE DROP SUBPARTITION to drop a subpartition of a composite *-[range | list] partitioned table To preserve the data in the partition, use the MERGE PARTITION statement instead of the DROP PARTITION statement. For information about merging a partition, refer to

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Managing Data in Oracle Database With ILM

Managing Data in Oracle Database With ILMInformation today comes in a wide variety of types, for example an e-mail message, a photograph, or an order in an Online Transaction Processing (OLTP) System. After you know the type of data and how it is used, you have an understanding of what its evolution and final disposition is likely to be. One challenge facing each organization is to understand how its data evolves and grows, monitor how its

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

Oracle ASM Settings Specific to VLDBs

Oracle ASM Settings Specific to VLDBsConfiguration of Oracle Automatic Storage Management for VLDBs is not very different from Oracle ASM configuration for non-VLDBs. Certain parameter values, such as the memory allocation to the Oracle ASM instance, may need a higher value. Oracle Database supports Oracle ASM variable allocation units. Large variable allocation units are beneficial for environments that use large sequential I/O operations.

Database VLDB and Partitioning Guide, 12c Release 1 (12.1)

About Exchanging a Subpartition of a *-List Partitioned Table

About Exchanging a Subpartition of a *-List Partitioned TableThe semantics of the ALTER TABLE EXCHANGE SUBPARTITION are the same as described previously in \" Exchanging a Subpartition of a *-Hash Partitioned Table \".





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