Update current view snapshot hangs

Update current view snapshot hangs while inserting the records into AD_PATCH_HIST_TEMP table.
Issue resolved by gathering the statistics on some of the AD_ tables.
exec fnd_stats.gather_table_stats('APPLSYS','AD_SNAPSHOT_FILES');exec fnd_stats.gather_table_stats('APPLSYS','AD_SNAPSHOT_BUGFIXES');exec fnd_stats.gather_table_stats('APPLSYS','AD_SNAPSHOTS');exec fnd_stats.gather_table_stats('APPLSYS','AD_FILE_VERSIONS');exec fnd_stats.gather_table_stats('APPLSYS','AD_CHECK_FILE_TEMP');exec fnd_stats.gather_table_stats('APPLSYS','AD_PATCH_HIST_TEMP');exec fnd_stats.gather_table_stats('APPLSYS','AD_SNAPSHOT_FILES_TEMP');exec fnd_stats.gather_table_stats('APPLSYS','AD_FILES');