Change an environment's flags

Sets or clears flags on an open environment. Only the flags 'libmdbx' documents as changeable at any time can be set this way — mdbx_flags()$runtime marks them; the rest are fixed when the environment is opened.

Usage

mdbx_env_set_flags(env, flags, on = TRUE)

Arguments

env

An mdbx_env object, from mdbx_env_open().

flags

A character vector of flag names — see mdbx_flags().

on

TRUE to set the flags, FALSE to clear them.

Value

NULL, invisibly.

Details

This is refused while a transaction is open, because 'libmdbx' serializes flag changes against the writer lock and would return MDBX_BUSY. Changing durability between transactions is the intended use: relax it for a bulk load, restore it and call mdbx_env_sync() afterwards.

See also

mdbx_flags(), mdbx_env_get_flags(), mdbx_env_sync()

Examples

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

# Bulk load without paying for a flush per commit.
mdbx_env_set_flags(env, "SAFE_NOSYNC")
for (i in 1:10) {
  mdbx_with_write(env, function(txn) mdbx_put(txn, sprintf("k%d", i), "v"))
}

# Then make it durable again, and flush what is outstanding.
mdbx_env_set_flags(env, "SAFE_NOSYNC", on = FALSE)
mdbx_env_sync(env)

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