I dont think that the problem cames from transport map 1-element caching, because the destination is variable, we have millions of email addresses. I made some tests with mysql general logging enabled and i found that when mysql lookup table checks a transport for a destination it does a lookup for em...@domain.tld domain.tld .tld but the lookup for * is done just once, but for the rest it does all the time. This is how it was designed to be the * lookup?
> What means this 1-element cache? it caches the last lookup? > Right. The cache is not specific to mysql, but is a feature of the trivial-rewrite transport lookup. This is only likely to be noticed when you use mysql-based transport_maps and a high percentage of the queue is for a single destination. This is not configurable. The workaround is to use a hash: or cdb: table, which triggers a restart of trivial-rewrite upon changes -- but note that frequent restarts of trivial-rewrite may be bad for performance.
