|Oracle® TimesTen In-Memory Database Reference
11g Release 2 (11.2.2)
Part Number E21643-16
The following sections list all TimesTen system limits and defaults.
Specific operating system limits may take precedence over these values. For more information, see "Installation prerequisites" in Oracle TimesTen In-Memory Database Installation Guide.
|Description||32-bit Value||64-bit Value|
|Maximum number of subscriber databases in a replication scheme that is not an active standby pair.||128||128|
|Maximum number of propagators in a replication scheme. Each propagator can have the maximum number of subscribers.||128||128|
|Maximum number of subscriber databases in an active standby pair.||127||127|
|Minimum database size (bytes). Size includes both the permanent and temporary space required to perform operations on the database.||32 MB||32 MB|
|Maximum length for a fixed-length column (bytes).||8,300||8,300|
|Maximum number of columns in a table.||1,000||1,000|
|Maximum number of columns in an
|Maximum number of columns in a
|Maximum cumulative length of a row's fixed-length columns (bytes).||32,768||32,768|
|Maximum length for a varying-length column (bytes).||222 = 4,194,304||222 = 4,194,304|
|Maximum length for a replicated column.||4 MB
16 MB for columns with
16MB for columns with
|Maximum number of concurrent connections to a database (including system connections).||2047||2047|
|Maximum number of concurrent application connections to a database (may be limited by semaphore configuration or
|Maximum number of connections (system and application) across all databases in an instance.||2048||2048|
|Maximum number of concurrent client connections to a TimesTen instance.
Note: Some instances may support a slightly smaller maximum number of connections depending on such things as whether the database is shared or replicated and operating system limits. Most configurations support no less than 2,000 connections.
|Maximum length of database names.||32||32|
|Maximum length of the path name for a database in an asynchronous writethrough cache group||248||248|
|Maximum number of projected expressions in a
|Maximum length of string specifying a join order.||1,024||1,024|
|Maximum number of columns in an index (or primary key).||16||16|
|Maximum length of basic names.||30||30|
|Maximum length of displayed predicate string in the
|Maximum length of SQL statement, including the
|Maximum number of table references in an SQL query.||24||24|
|Maximum number of indexes on a table.||500||500|
|Maximum number of partitions in a table.||999||999|
|Maximum number of prepared PL/SQL statements per connection.||5000||5000|
|Maximum number of recently-used PL/SQL blocks that can be cached per session.||5000||5000|
|Maximum number of concurrent shared memory segment client/server connections per TimesTen instance.||512||512|
|Maximum size of IPC shared memory segment for client/server connections||1 gigabyte||1 gigabyte|
|Maximum number of allocated statement handles per shared memory segment client/server connection.||512||512|
|Maximum depth of nesting subqueries.||Equal to the maximum number of table references in a SQL query.||Equal to the maximum number of table references in a SQL query.|
|Maximum error message length for applications that specify an error message length (for example, through a call to
Each process connected to a TimesTen database keeps at least one operating-system file descriptor open from the time of the first connection until the process terminates. Additional file descriptors may be opened for each database connection:
Connections to databases that have logging to disk enabled require an additional two file descriptors for the duration of the connection.
An additional file descriptor is needed for the duration of database checkpoints issued by the process.
Additional file descriptors may be opened during transaction commit or rollback operations.
For multithreaded applications that maintain many concurrent TimesTen database connections, the default number of open files permitted to each process by the operating system may be too low.
On Solaris, the default limit is 256 open files and may be raised for a session with the
ulimit command (
csh users). You can also set the per-process limit programmatically with
On AIX, the limit is 2,048 open files, so you are not likely to encounter problems.
On Linux, the default limit is 1,024 open files, so you are not likely to encounter problems.
On Windows, the default limit is at least 2,000 open files, so you are not likely to encounter problems.
Most of the open file descriptors are used for reading and writing database recovery log files. If a process fails to open a log file, the database is marked as requiring recovery and all current connections to the database are terminated.