Immediately after reindexing the Catalog URL Rewrites, Magento says we need to reindex them again. I'm using the command line to run indexer.php as a background task:
nohup php indexer.php --reindex catalog_url > /home/ubuntu/rewrites_index_20130218 2> /home/ubuntu/rewrites_index_20130218.err < /dev/null &
The Index Management screen shows "Processing" on the relevant row while this runs, but reverts to "Reindex Required" once completed.
The output file
rewrites_index_20130218 says that the reindex completed successfully. The
rewrites_index_20130218.err is empty. The files
exception.log in Magento's log folder are both clean.
On a previous attempt last night, the index failed due to too many MySQL locked tables. I increased the MySQL
innodb_buffer_pool_size and restarted MySQL and we're not getting that issue now.
I have deliberately run the indexing when I know for certain that nobody from the team is working in the Magento admin area.
What would cause the rewrites table to need to be reindexed so often, or if that's not obvious, what steps could I take to identify the cause of the problem?