The tables below present logical and physical system limits for
ALLBASE/SQL. The values show the maximums permitted by the
ALLBASE/SQL software. In practice, lower maximums may be
imposed by the operating system or hardware environment in
which ALLBASE/SQL is installed. In addition, ALLBASE/SQL uses some space
per page for internal data structures. This leaves less than
a complete page available to the user for tuple data and
header storage. Refer to the "Logical Design" and "Physical Design"
chapters for methods of determining the amount of space available to the user.
Page size is 4096 bytes, except for log pages, which are 512 bytes.
Table A-1 System Control Limits
| Name of Limit | Value |
|---|
| Multiuser DBEnvironments per system | No limit |
| Single-user DBEnvironments per system | No limit
|
| Number of concurrent sessions | Limited by Runtime Control Block Allocation |
| Number of concurrent transactions | 2 to 240 (when 240 are active, additional transactions are placed in a wait queue)
|
| Number of concurrent connections per user | 1 to 32 |
| Number of concurrent users | No limit
|
| Timeout value | 1 to 2,147,483,647 seconds
or 1 to 35,791,394 minutes
|
Table A-2 Logical Data Limits
| Name of Limit | Value
|
|---|
| Tables per DBE | 231 - 1 |
| Maximum columns per table | 1023 |
| Bytes per row | (NumberOfColumns+1)*2+SumOfColumnLengths <= 4000 (for the VARCHAR data type, ColumnLength equals ColumnValueLength) |
| Bytes per column | 3996 |
| Bytes per long column | 231 - 1
|
| Views per DBE | 231 - 1 |
| Maximum columns per view | 1023 |
| Maximum parameters per procedure | 1023 |
| Maximum result columns per procedure | 1024
|
| Indexes per DBEnvironment | 231 - 1 |
| Maximum columns per B-tree index or hash | 16 |
| Maximum columns per virtual index (PCR) | 15 |
| Maximum B-tree or hash key size | (NumberofKeyColumns + 2)*2 +
SumofColumnLengths +8 <= 1024 |
| Maximum virtual index (PCR) key size | (NumberofKeyColumns + 3)*2 +
SumofColumnLengths +10 <= 1024
|
| Maximum sort columns | 1023 |
| Maximum sort tuple size | (NumberOfSortColumns + 1)*2 +
SumOfSortColumnLengths <=4000
(for the VARCHAR data type, ColumnLength equals ColumnValueLength)
|
Table A-3 Space Management Limits
| Name of Limit | Value |
|---|
| Tables per statement (including tables underlying views) | 31 |
| Query blocks per query | 16
|
| Data and index page size | 4096 bytes |
| Log page size | 512 bytes
|
| Pages per DBEFile (except DBEFile0) | 2 to 219 - 1 |
| Pages per DBEFile0 (one per DBEnvironment) | 150 to 219 - 1 |
| DBEFiles per DBEnvironment | 32767 |
| Pages per DBEFileSet (when there is only one) | (32767)(219 - 1) |
| Pages per DBEnvironment (all DBEFiles combined) | (32767)(219 - 1)
|
| Log size (pages) | 250 to 222 - 1 |
| Maximum size of a single log file | 4 gigabytes |
| Maximum number of log files | 34 |
| Maximum size of log file space | 136 gigabytes
|
| Number of data buffer pages | 15 to the limit of shared memory |
| Number of log buffer pages | 24 to 1024 |
| Number of runtime control block pages | 17 to 2000
|
| ISQL command size | 32K bytes |
| Maximum levels of nesting for ISQL STARTs per user | 10 |
| SQL command size | 32K bytes
|
| Number of pages per file opened in a
TempSpace (MaxFilePages) | 128 to 524284
|
