Public memory durations
The DataBlade API memory-management functions support several public memory durations. A UDR can use a public memory duration for most dynamic allocations of memory.
The DataBlade
API provides
the public memory durations that the following table shows.
| Public memory duration | Memory-duration constant | Description |
|---|---|---|
| For the duration of one iteration of the UDR | PER_ROUTINE, PER_FUNCTION | The database server frees the memory after the UDR returns. |
| For the duration of the current SQL subquery | PER_COMMAND | The database server frees memory when an SQL command terminates. |
| For the duration of the current SQL statement | PER_STATEMENT (Deprecated) | The database server frees memory when an SQL statement terminates. |
| For the duration of the execution of the current SQL statement | PER_STMT_EXEC | The database server frees memory when the execution of an SQL statement is complete. |
| For the duration of the current prepared SQL statement | PER_STMT_PREP | The database server frees memory when a prepared SQL statement terminates. |
The PER_ROUTINE and PER_COMMAND memory durations are the most common for C UDRs. The memory-duration constants in Table 1 are of type MI_MEMORY_DURATION, which the memdur.h header file defines. All memory-duration constants in Table 1 are also declared in the memdur.h header file.