m4_comment([$Id: env_set_tx_max.so,v 10.47 2006/06/19 22:25:31 bostic Exp $])

define(M4PAGELOCAL, [dbenv_set_tx_max, dbenv_get_tx_max])
include(m4/m4.seealso)

m4_pf_header(m4_ref(dbenv_set_tx_max),
ifelse(M4API, C_API, [dnl
int
DB_ENV-__GT__set_tx_max(DB_ENV *dbenv, u_int32_t max);
m4_blank
int
DB_ENV-__GT__get_tx_max(DB_ENV *dbenv, u_int32_t *tx_maxp);
])
ifelse(M4API, CXX_API, [dnl
int
DbEnv::set_tx_max(u_int32_t max);
m4_blank
int
DbEnv::get_tx_max(u_int32_t *tx_maxp);
]))

m4_p([dnl
Configure the m4_db database environment to support at least m4_arg(max)
active transactions.  This value bounds the size of the memory allocated
for transactions.  Child transactions are counted as active until they
either commit or abort.])

m4_p([dnl
Transactions that update multiversion databases are not freed until the
last page version that the transaction created is flushed from cache.
This means that applications using multi-version concurrency control may
need a transaction for each page in cache, in the extreme case.])

m4_p([dnl
When all of the memory available in the database environment for
transactions is in use, calls to m4_ref(txn_begin) will fail (until some
active transactions complete).  If this interface is never called, the
database environment is configured to support at least 100 active
transactions.])

m4_env_config(dbenv_set_tx_max, [number of active transactions],
set_tx_max, [the number of transactions])

m4_scope_env(dbenv_set_tx_max)
m4_when_envopen(dbenv_set_tx_max, ignored)
m4_return(dbenv_set_tx_max, std)

m4_parambegin
m4_param(max, [dnl
The m4_arg(max) parameter configures the minimum number of
simultaneously active transactions supported by m4_db database
environment.])
m4_paramend

m4_err(dbenv_set_tx_max,
einval, [the method was called after m4_ref(dbenv_open) was called])

m4_pf_getter(dbenv_get_tx_max, number of active transactions,, tx_maxp)

m4_seealso(DbTxn)
m4_page_footer