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| -rw-r--r-- | README.md | 5 | ||||
| -rw-r--r-- | db.go | 5 |
2 files changed, 10 insertions, 0 deletions
@@ -87,6 +87,11 @@ are not thread safe. To work with data in multiple goroutines you must start a transaction for each one or use locking to ensure only one goroutine accesses a transaction at a time. Creating transaction from the `DB` is thread safe. +Read-only transactions and read-write transactions should not depend on one +another and generally shouldn't be opened simultaneously in the same goroutine. +This can cause a deadlock as the read-write transaction needs to periodically +re-map the data file but it cannot do so while a read-only transaction is open. + #### Read-write transactions @@ -401,6 +401,11 @@ func (db *DB) close() error { // will cause the calls to block and be serialized until the current write // transaction finishes. // +// Transactions should not be depedent on one another. Opening a read +// transaction and a write transaction in the same goroutine can cause the +// writer to deadlock because the database periodically needs to re-mmap itself +// as it grows and it cannot do that while a read transaction is open. +// // IMPORTANT: You must close read-only transactions after you are finished or // else the database will not reclaim old pages. func (db *DB) Begin(writable bool) (*Tx, error) { |