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Oracle® TimesTen In-Memory Database System Tables and Limits Reference
Release 11.2.1

Part Number E17114-01
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3 System Limits

The following sections list all TimesTen system limits and defaults.

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 replication subscriber data stores. (For Active/Standby schemes, one subscriber value is used by the system.) 128 128
Minimum data store size (bytes). Size includes both the permanent and temporary space required to perform operations on the data store. 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 ORDER BY clause. 1,000 1,000
Maximum number of columns in an GROUP BY clause. 1,000 1,000
Maximum cumulative length of a row's fixed-length columns (bytes). 32,768 32,768
Maximum number of rows in a table. 256 M =31 268,435,256 (231-1) = 2,147,483,647
Maximum length for a varying-length column (bytes). 222 = 4,194,304 222 = 4,194,304
Maximum length for a replicated column 4 MB 4 MB
Maximum number of concurrent connections to a data store. 2047 2047
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 data store is shared or replicated and operating system limits. Most configurations support no less than 2,000 connections.

25,000 25,000
Maximum length of data store names. 32 32
Maximum length of the path name for a data store in an asynchronous writethrough cache group 248 248
Maximum number of projected expressions in a SELECT statement. 32,767 32,767
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 PLAN table. 1,024 1,024
Maximum length of SQL statement, including the NULL terminator. 409,600 409,600
Maximum number of table references in an SQL query. 24 24
Maximum number of indexes on a table. 32 32
Maximum number of partitions in a table 999 999
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 an SQL query. Equal to the maximum number of table references in an SQL query.
Maximum error message length for applications that specify an error message length, for example through a call to SQLError. 512 512

Limits on number of open files

Each process connected to a TimesTen data store 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 data store connection:

For multithreaded applications that maintain many concurrent TimesTen data store connections, the default number of open files permitted to each process by the operating system may be too low.

Most of the open file descriptors are used for reading and writing data store recovery log files. If a process fails to open a log file, the data store is marked as requiring recovery and all current connections to the data store are terminated.

Path names

TimesTen does not support file path names that contain multibyte characters. Make sure that the installation path, data store path, transaction log path, and temporary file path do not contain any multibyte characters.