Reads one or more tables and indexes from the database and stores the data rows or index nodes in caches if they exist.
1 – Description
The RMU Populate_Cache command allows one or more tables and indexes to be read from the database and stored in caches if they exist. Sorted indexes are read top-down, one index level at a time. Hashed indexes are read by sequentially scanning the storage areas containing the hashed indexes and fetching all nodes and the system record from each database page. Data table rows are read by sequentially scanning the storage areas containing the table and fetching all rows of the relation.
2 – Format
(B)0[mRMU/Populate_Cache root-file-spec [4mCommand[m [4mQualifiers[m x [4mDefaults[m x /Index=index-list x None /[No]Log x Current DCL verify switch /[No]Only_Cached x /Only_Cached /Statistics_Interval=n x /Statistics_Interval=10 /Table=table-list x None /Transaction_Type=transaction-mode x /Transaction-Type=Automatic
3 – Parameters
3.1 – root-file-spec
Specifies the database root (.rdb) file. The default file type is .rdb.
4 – Command Qualifiers
4.1 – Index
Index=Index-list Specifies one or more indexes to fetch. All nodes are fetched from each index. If you list multiple indexes, separate the index names with a comma and enclose the list within parentheses. Wildcard characters asterisk (*) and percent sign (%) are allowed.
4.2 – Log
Log Nolog Specifies whether the processing of the command is reported to SYS$OUTPUT. Specify the Log qualifier to request that information about the operation be displayed, and the Nolog qualifier to prevent it. If you specify neither qualifer, the default is the current setting of the DCL verify switch. (The DCL SET VERIFY command controls the DCL verify switch.)
4.3 – Only Cached
Only_Cached Noonly_Cached Specifies whether table or index content is to be read only if the table or index has an associated row cache. The default is to read data only from objects that have a cache. If the Noonly_ Cached qualifier is specified, then all data from the specified tables or indexes is read.
4.4 – Statistics Interval
Statistics_Interval=n Specifies if statistics information is to be periodically displayed during the populate operation. The default for this qualifier is an interval of 10 seconds. If you do not use this qualifier no statistics are displayed.
4.5 – Table
Table=table-list Specifies one or more tables to be processed. All rows are fetched from each table. If you list multiple tables, separate the table names with a comma, and enclose the list within parentheses. Wildcard characters asterisk (*) and percent sign (%) are allowed.
4.6 – Transaction Type
Transaction_Type=option Allows you to specify the transaction mode for the transactions used to perform the analyze operation. Valid options are: o Automatic o Read_Only o Noread_Only You must specify an option if you use this qualifier. If you do not specify any form of this qualifier, the Transaction_Type=Automatic qualifier is the default. This qualifier specifies that Oracle RMU is to determine the transaction mode. The Transaction_Type=Read_Only qualifier specifies the transactions used to perform the analyze operation be set to read-only mode. When you explicitly set the transaction type to read-only, snapshots need not be enabled for all storage areas in the database, but must be enabled for those storage areas that are read. Otherwise, you receive an error and the analyze operation fails. You might select this option if not all storage areas have snapshots enabled and you are analyzing objects that are stored only in storage areas with snapshots enabled. In this case, using the Transaction_Type=Read_Only qualifier allows you to perform the analyze operation and impose minimal locking on other users of the database. The Transaction_Type=Noread_Only qualifier specifies that the transactions used to for the analyze operation be set to read/write mode. You might select this option if you want to eradicate the growth of snapshot files that occurs during a read- only transaction and are willing to incur the cost of increased locking that occurs during a read/write transaction.