Enabling the Store Diff Info setting means that Fisheye will store information about file diffs in its database, that is, Fisheye will store a summary of what lines are added and removed between subsequent versions of the same file. You will still be able to view file diffs regardless of whether this setting is enabled or disabled.

Please note, you need to perform a full re-index of your repository after enabling this setting for Fisheye to collect the diff information for all revisions in your repository.

Please also note that:

• Disabling the Store Diff Info setting will disable per-author line graphs.
• Disabling the Store Diff Info setting also removes the author/revision information in the diff display.
• Disabling the Store Diff Info setting will disable blame calculation when indexing. See Blame calculations.
  
• Diff information is always stored for CVS repositories. Note, that a full re-index is required to enable per author charts after upgrading from Fisheye 1.4.3 or earlier.
• Enabling the Store Diff Info setting will allow Fisheye to perform text searches of lines added and removed, in addition to the text search of the trunk head.
• Enabling the Store Diff Info setting for Perforce repositories will force Fisheye to make extra requests to your depot in order to collect the diffs. This may substantially increase the time it takes to scan your repository. If your Perforce repository was created before Fisheye 1.5, this setting will be disabled by default.
• Scan times for other repositories, like CVS and Subversion, are not as affected by the Store Diff Info setting as Perforce since the diffs are still fetched but disabling this option will still prevent the overhead of indexing the data which can still be significant.