HyperDB (revisiting)

In reference to this, which is closed and (probably) should not be:

https://ww.wp.xz.cn/support/topic/incompatible-with-hyperdb-and-sql_calc_found_rows-deprecation/

The problem here is two fold. HyperDB itself doesn’t check for anything between SELECT and SQL_CALC_ROWS_FOUND (in this case you use DISTINCT), which in itself may be an issue (I asked over there).

I have fixed this incompatibility by simply updating the preg in hyperDB and modifying EM to look for the hyperdb flag ($wpdb->last_found_rows_result) set for automatic SELECT ROWS_FOUND() when using SQL_CALC_FOUND_ROWS. For example, in classes/em-events.php around line 215:

self::$num_rows_found = $wpdb->last_found_rows_result ? $wpdb->last_found_rows_result : $wpdb->get_var(‘SELECT FOUND_ROWS()’);

You could integrate easily with HyperDB in this sort of case, but you’d have to drop the DISTINCT.

On the other hand, ya’ll should abandon this method (SQL_CALC_FOUND_ROWS) altogether as it’s deprecated by MySQL. Just run a second select query for COUNT(*) in this if/then statement rather than SELECT FOUND_ROWS() altogether — in the event pagination was even needed (I don’t think I’m even using it actually). I’d rather just mod one plugin rather than yours and HyperDB, but this fix is actually quicker in my case than trying to sort out your logic for post counting / pagination.

My solution sucks since it would require HyperDB to fix their own dealings with SQL_CALC_FOUND_ROWS not allowing statements between it and SELECT (which I think is likely faulty to begin with since it doesn’t follow valid SQL syntax, but maybe there’s some sage-like reason). Alas, a plugin as popular as yours should probably not be outright incompatible with Automattic’s own DB extension they use widely on their own clustering solutions, but that’s a different matter.

Either case, I can’t use read-write split replication servers via HyperDB with Events Manager and that throws a gear in my cogs =P

It’s been 9 months since the aforementioned post, would be nice to get an update on the matter.