# Redundant Calculations in OstiumTrading::openTrade() Low/Info · Three Sigma · RWA perpetuals DEX · 19th February, 2024 Finding 3S-OS-N08 of the Ostium security review. - Protocol: https://www.ostium.com/ - Report: /reports/ostium - Source: https://cdn.sanity.io/files/qoqld077/production/a95b9c69e0f65d1d6b0e649f0d62a362358ca8ce.pdf --- ### Description When opening a LIMIT or STOP order, the first empty index is calculated using OstiumTradingStorage::firstEmptyOpenLimitIndex() on [L209](https://github.com/0xOstium/smart-contracts-threeSigma/blob/1b70cffbac621d39e321c159e45c048b703add92/src/OstiumTrading.sol#L209). However, the same function is executed again in OstiumTradingStorage::storeOpenLimitOrder() on [L233](https://github.com/0xOstium/smart-contracts-threeSigma/blob/1b70cffbac621d39e321c159e45c048b703add92/src/OstiumTradingStorage.sol#L233), which results in the index property being overridden with the same value. Similarly, the current block number is retrieved on [L211](https://github.com/0xOstium/smart-contracts-threeSigma/blob/1b70cffbac621d39e321c159e45c048b703add92/src/OstiumTrading.sol#L211) in OstiumTrading, and then on [L231](https://github.com/0xOstium/smart-contracts-threeSigma/blob/1b70cffbac621d39e321c159e45c048b703add92/src/OstiumTradingStorage.sol#L231) in OstiumTradingStorage. ### Recommendation Remove the redundant overriding of these variables from OstiumTradingStorage::storeOpenLimitOrder(). ### Status Addressed in [#3d116cd](https://github.com/0xOstium/smart-contracts-threeSigma/pull/58/commits/3d116cd22fbfdaeda8fafbc84176095708316641).