This paper presents the efficiency of a sensing database and caching (SDB) for cognitive radio systems. The proposed SDB stores regulatory information from regulatory databases, and contains sensing information by distributed sensing schemes. Preliminary information processing for instance indexing, sorting, or applying some models or algorithms, etc. can be performed for the stored data. Available information and the results of the information processing are provided to cognitive radios in order to determine available spectrum and to facilitate dynamic spectrum access at lower sensing cost but higher sensing quality. The SDB is implemented in local networks, therefore information exchange between SDB and the cognitive radios can be realized at low latency and the amount of signaling traffic to global network can be reduced. This paper analyzes the effect of SDB and the performance evaluation was done in a certain condition. As a result, by deploying SDB a system can achieve up to 20% of reduction of sensing activities and maximum 1.3 times higher sensing quality.