I have a MySql to Access 2003 table join that is very slow.
I need to bring up appointment history from a mysql table that applies to a customer in the table. The table doesn't contain the kept status. The kept status is in an access table. The Access generated join is very slow.
How can it be optimized?
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what arthur says would be correct -- if you created the copy once and let it go stale.
by and large, it is faster to:
completely copy the TABLE into a local copy , then JOIN, and output
vs
JOINing remotely.
probably, the ideal solution is to do a periodic syncronization (say 1x / hr). The obsession with live data is broadly based on mistaken assumptions. In reality, most "live" data sources utilize a caching mechanism similar to this.
One way to avoid any problems is to have a trigger method of some sort. i.e. if you have a timestamp field, you can look at the timestamp to see if you need to refresh the local copy.
....
the basic problem is that the access JOIN cannot use the MySQL index when JOINing remotely, so it essentially does a table scan for each row in your table. A different approach would be to upload the statuses into a MySQL table and perform the join there.
The main table is huge and as indicated it would require code to keep in sync.
With SQL server one could make a stored procedure which would create a local recordset which would be a passthrough query in Access. This would be a join parameter based query that picks a small subset directly from the MySql side and joins this small result set with the Access table.
Is something like this possible with MySql?
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by: cwood-wm-comPosted on 2009-09-23 at 12:58:45ID: 25407245
You should index every field that is part of the join (on both tables), every field used in sorting, and every field used with criteria. Indexing can GREATLY speed joined queries.
-Chuck