I would propose that you implement a "per point of sale" perl based cache. The tracking of changes outside this point of sales should be done by triggers on the reservation table by the backend database.

Simultaneity issues should be handled definitely by the backend database, because databases are made to support the ACID requirements. Transactions are your friend. Although these measures come with a performance penalty they insure a consistent system. This is the "conditio sine qua non" (not-without-it-condition) for your kind of application.

In reply to Re^5: OT: Scalable web application architecture by dokkeldepper
in thread OT: Scalable web application architecture by badaiaqrandista

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