Reuse data in a subset relation

saf_use_written_subset_relation is a function defined in rel.c.

Synopsis:

int saf_use_written_subset_relation(SAF_ParMode pmode, SAF_Rel *rel, SAF_Rel *oldrel, hid_t A_buf_type, hid_t B_buf_type, SAF_Db *file)

Formal Arguments:

  • pmode: the parallel mode.
  • rel: The handle for the relation to be updated.
  • oldrel: The handle for the relation pointing to the data to be re-used.
  • A_buf_type: The type of data that would be written for the A buffer (see saf_write_subset_relation) if this call was actually doing any writing.
  • B_buf_type: The type of data that would be written for the B buffer (see saf_write_subset_relation) if this call was actually doing any writing.
  • file: The file the data would be written to if this call was actually doing any writing.

Description: This call binds data for an existing relation to a new relation. This call can be used in place of a saf_write_subset_relation call if the data that would have been written in the subset relation is identical to some other relation data already written to the database.

Preconditions:

  • pmode must be valid. (low-cost)
  • rel must be a valid relation handle. (low-cost)
  • oldrel must be a valid relation handle. (low-cost)
  • oldrel must be same as rel to re-use data written to it. (no-cost)
  • oldrel must be same as rel to re-use data written to it. (no-cost)

Return Value: The constant SAF__SUCCESS is returned when this function is successful. Otherwise this function either returns an error number or throws an exception, depending on the value of the library’s error handling property.

See Also: