As described by Julian earlier this month, Julian, Philip and I observed that the BASE_NODE, WORKING_NODE and NODE_DATA tables have many fields in common. Notably, by introducing the NODE_DATA table, most fields from BASE_NODE and WORKING_NODE already moved to a common table.
The remaining fields (after switching to NODE_DATA *and* SINGLE-DB) on the side of WORKING_NODE are the 2 cache fields 'translated_size' and 'last_mod_time'. Apart from those two, there are the indexing fields wc_id, local_relpath and parent_relpath. In the end we're storing *lots* of bytes (wc_id, local_relpath and parent_relpath) to store 2 64-bit values. On the side of BASE_NODE, we end up storing dav_cache, repos_id, repos_path and revision. The NODE_DATA table already has the fields original_repos_id, original_repos_path and original_revision. When op_depth == 0, these are guaranteed to be empty (null), since they are for working nodes with copy/move source information. Renaming the three fields in NODE_DATA to repos_id, repos_path and revision, generalizing their use to include op_depth == 0 [ofcourse nicely documented in the table docs], BASE_NODE would be reduced to a store of the dav_cache, translated_size and last_mod_time fields. By subsuming translated_size and last_mod_time into NODE_DATA, neither WORKING_NODE nor BASE_NODE will need to store these values anymore. This eliminates the entire reason of existence of WORKING_NODE. BASE_NODE then only stores dav_cache. Here too, it's probably more efficient (in size) to store dav_cache in NODE_DATA to prevent repeated storage of wc_id, local_relpath and parent_relpath in BASE_NODE. In addition to the eliminated storage overhead, we'd be making things a little less complex for ourselves: UPDATE, INSERT and DELETE queries would be operating only on a single table, removing the need to split updates across multiple statements. This week, I was discussing this change with Greg on IRC. We both have the feeling this should work out well. The proposal here is to switch (WORKING_NODE, NODE_DATA, BASE_NODE) into a single table --> NODES. Comments? Fears? Enhancements? Bye, Erik.
