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Flush an environment to disk

Source: R/flags.R
mdbx_env_sync.Rd

Writes and flushes any data a relaxed durability mode has left outstanding. With the default durability there is never anything to flush, because mdbx_txn_commit() has already done it.

Usage

mdbx_env_sync(env, force = TRUE, nonblock = FALSE)

Arguments

env

An mdbx_env object, from mdbx_env_open().

force

If TRUE, always flush. If FALSE, flush only if a threshold set on the environment has been reached, which is 'libmdbx”s polling mode.

nonblock

If TRUE, give up rather than wait when another process is in a write transaction. The wait is signalled as an MDBX_BUSY error.

Value

Invisibly, TRUE if there was unsynced data and it was written, or FALSE if nothing was pending.

Details

Under "SAFE_NOSYNC" this also establishes a new steady commit point, which is what lets 'libmdbx' start reusing freed pages again — so it bounds file growth as well as making data durable.

See also

mdbx_flags(), mdbx_env_set_flags()

Examples

path <- tempfile(fileext = ".mdbx")
env <- mdbx_env_open(path, flags = "SAFE_NOSYNC")

mdbx_with_write(env, function(txn) mdbx_put(txn, "k", "v"))

# The commit above flushed nothing; this does.
mdbx_env_sync(env)

mdbx_env_close(env)
unlink(c(path, paste0(path, "-lck")))