Intelligent merging for efficient updates in columnar databases are disclosed, including: determining a current age associated with a row in a database, wherein the database comprises a write storage and a read storage, wherein the row is located in the write storage; determining a set of one or more merge criteria based at least in part on a modification age distribution, wherein the modification age distribution is dynamically determined based at least in part on previous transactions at the database; determining whether the current age meets the set of merge criteria; and in response to a determination that the current age meets the set of merge criteria, merging the row from the write storage into the read storage.