Task #6701 (new)
Opened 13 years ago
Last modified 13 years ago
Bug: exponential slow down without setWriteSequentially in ExporterI — at Version 1
Reported by: | jamoore | Owned by: | mlinkert-x |
---|---|---|---|
Priority: | critical | Milestone: | OMERO-Beta4.3.2 |
Component: | Performance | Version: | n.a. |
Keywords: | n.a. | Cc: | a.herbert@…, cxallan, jburel |
Resources: | n.a. | Referenced By: | n.a. |
References: | n.a. | Remaining Time: | n.a. |
Sprint: | n.a. |
Description (last modified by jmoore)
See: https://www.openmicroscopy.org/community/posting.php?mode=reply&f=6&t=814
From Alex:
I did a lot of reading of the code in the process and noticed that the sequential flag was not set on the BioFormats ImageWriter?. This means that each time a new plane is written to the TIFF file, BioFormats reads the entire file to locate the positions of all the current IFD entries (see method loci.formats.tiff.TiffSaver?.writeImageIFD(...)). If the current plane being written is less than the total count of IFD entries then the correct IFD entry is extracted for use.
Since the planes are written using incremental plane numbers I do not think this condition will ever be met. Thus it is safe to set the sequential flag to true.