Coordinator bug causes 15-hour stoppage in IOTA

The IOTA Tangle had stopped processing transactions on December 29, around 11 am. According to The Block, the bug was detected and fixed 15 hours post the stoppage. The system could still transfer data during the stoppage and users were able to read transactions. IOTA’s co-founder David Sønstebø said that the bug was “minor.” He also said that the issue will be addressed when the project moves away from using the Coordinator, in an upgrade called Coordicide. He stated:

Whatever the bug is, there is no reason to panic over such a minor issue pre-Coordicide. This is precisely why Coordicide takes time, one can’t execute it until all possible kinks have been ironed out.

The crypto community criticized IOTA’s leadership for calling the issue “minor.” Instead of blockchain, IOTA uses a directed acyclic graph or DAG. This system has its unique challenges and potential compared to blockchain. Instead of mining or staking, transactions are validated by confirmation from at least two other transactions.

Nevertheless, for these transactions to get fully validated, a centralized node is necessary. This node, that is controlled by the IOTA Foundation is called Coordinator. DAG requires further development in order to work without such a bottleneck. The IOTA Foundation announced earlier in May 2019 that it was planning to remove the Coordinator in an upgrade known as Coordicide. Coordicide is scheduled for completion in late 2020. 

According to the bug fix, the IOTA Reference Implementation “didn’t account for a transaction that was shared between two distinct bundles. Once it marked it as ‘counted’ in one bundle, it was ignored for the next bundle. This lead to a corrupt ledger state.”