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Managing the Thumbnailing Process
The main function of the MetaData Service is to update digital resource records corresponding to the files/folders that have been recognized by the FSS as added or modified. Along with basic file information and other metadata, the MDS provides digital resource records with up-to-date image thumbnails and extended previews. For information on thumbnail and extended preview generation methods, refer to the “Thumbnail and Extended Preview Generation Methods” section of this guide.
Configuring the MDS includes specifying thumbnailing options on two levels. On the MDS snap-in level you provide option values that are propagated to all databases attached to the snap-in. The options set on the database level allow you to tune up the thumbnailing process for a particular database.
Configuring General Thumbnailing Options for the MDS
General thumbnailing options for the MDS are specified using the Thumbnailing tab of the MetaData Service Properties window. In addition, the General tab of this window allows you to specify whether the MDS will need to monitor its memory usage while generating image thumbnails/extended previews.
To configure general thumbnailing options for the MDS:
- Open the MetaData Service Properties window by right-clicking the MDS snap-in in the tree portion of the Management Console and selecting Properties from the popup menu; or selecting the MDS snap-in and clicking the Properties button
on the tool bar. - Click the General tab to specify whether the MDS should monitor its memory usage while processing files.
If the Monitor memory usage check box is left cleared, the MDS will use all memory available to generate thumbnails/extended previews. Sometimes, working in this mode may significantly slow the process of updating digital resource records, especially for huge graphic files. By setting limits for memory usage you instruct the MDS to exclude those files that cannot be processed using the amount of memory specified.
The maximum number of files that may be processed simultaneously. The MDS can simultaneously handle multiple addition and modification file events that have been recognized by the FSS. This number also controls how many simultaneous connections to the SQL Server will be available for the MDS to update digital resource records.
Whether the MDS should save thumbnailing results in the NTFS file system. By selecting the corresponding check box you instruct the MDS to use NTFS file streams to store the most recent thumbnail images and extended previews for digital resources residing in the NTFS file system. This approach allows the MDS to quickly obtain the up-to-date thumbnails/extended previews in situations when the full processing of NTFS folders/files is not required (for example, when the MDS handles the request to update the digital resource record for a graphic file whose content has not changed since the last update).
Whether the MDS should use QuickTime to generate thumbnails for PICT files. QuickTime is recommended as a preferred tool for processing PICT files as it has the most powerful capabilities for interpreting the PICT file format. Specify the transparent color for the PICT files if they are to be processed by QuickTime. This option is not available for editing (the “QuickTime” area is disabled) if QuickTime is not installed on the computer whose InterSync services you are configuring.
- Click OK to save the modifications you have made to the service properties and close the MDS Properties window.
You can further configure the thumbnailing process for a particular database by setting options located under the Options tab of the database’s Properties window.
Configuring Thumbnailing Options for an Attached Database
Configuring thumbnailing process for a database attached to the MDS snap-in includes specifying database interaction and file processing options.
You may also configure the thumbnailing process for a database while attaching it to the service snap-in of the MetaCommunications Management Console (refer to the “Attaching DSM Databases” section).
To configure thumbnailing options for a database attached to the MetaData Service snap-in:
- Open the database’s Properties window by right-clicking the appropriate database in the MetaData Service subtree of the MetaCommunications Management Console and selecting Properties from the popup menu; or selecting the database and clicking the Properties button
on the tool bar. - Click the Options tab to start specifying thumbnailing options.
The maximum number of simultaneous connections the MetaData Service can make to the Microsoft SQL Server. Even if set as unlimited (“0”), this number cannot exceed the value of the “Number of files to process simultaneously” parameter set for the service as described in the previous subsection.
The appropriate frequency with which the service scans the database to see whether the File System Service has recognized new digital resource addition and modification events*.*
The appropriate frequency with which the service should reload the database scheme and get updated information on thumbnailing methods associated with the file types registered in the database. For more information on file types and thumbnailing methods, please refer to refer to “Setting Up File Types” of this guide.
The interval between attempts to process locked files. If a file is locked (for example, being in use by the DSM client application), the MetaData Service will wait the specified number of seconds before attempting to process the file again.
The maximum number of attempts and interval between attempts to process unlocked files. Once a file becomes unlocked, the MDS is allowed to make the specified number of attempts to process the file and generate its thumbnail image/extended preview using the currently active thumbnailing method. If for any reason (for example, a file is corrupted) the MDS fails to process a file in the number of attempts specified, the presumption is made that no valid thumbnail/extended preview exists for the file. In this case, the MDS will scan the list of the thumbnailing methods defined for the appropriate file type, select the method with a lower priority and apply it during the next series of attempts. Note, that for all file types registered in the system the MDS will always succeed in generating thumbnail images using the Get Icon method that is guaranteed to find an icon. For more information on thumbnailing methods, please refer to the “Thumbnail and Extended Preview Generation Methods” section of this guide.
- Click OK to save the modifications you have made to the database properties and close the database’s Properties window.