2011-09-13 17:44:24 +00:00
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
< html xmlns = "http://www.w3.org/1999/xhtml" >
< head >
< meta http-equiv = "Content-Type" content = "text/html; charset=UTF-8" / >
< title > DB_ENV-> set_memory_init()< / title >
< link rel = "stylesheet" href = "apiReference.css" type = "text/css" / >
< meta name = "generator" content = "DocBook XSL Stylesheets V1.73.2" / >
< link rel = "start" href = "index.html" title = "Berkeley DB C API Reference" / >
< link rel = "up" href = "env.html" title = "Chapter / >
< link rel = "prev" href = "envset_isalive.html" title = "DB_ENV->set_isalive()" / >
< link rel = "next" href = "envset_memory_max.html" title = "DB_ENV->set_memory_max()" / >
< / head >
< body >
< div xmlns = "" class = "navheader" >
< div class = "libver" >
< p > Library Version 11.2.5.2< / p >
< / div >
< table width = "100%" summary = "Navigation header" >
< tr >
< th colspan = "3" align = "center" > DB_ENV-> set_memory_init()< / th >
< / tr >
< tr >
< td width = "20%" align = "left" > < a accesskey = "p" href = "envset_isalive.html" > Prev< / a > < / td >
< th width = "60%" align = "center" > Chapter
The DB_ENV Handle
< / th >
< td width = "20%" align = "right" > < a accesskey = "n" href = "envset_memory_max.html" > Next< / a > < / td >
< / tr >
< / table >
< hr / >
< / div >
< div class = "sect1" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
< h2 class = "title" style = "clear: both" > < a id = "envset_memory_init" > < / a > DB_ENV-> set_memory_init()< / h2 >
< / div >
< / div >
< / div >
< pre class = "programlisting" > #include < db.h>
int
DB_ENV-> set_memory_init(DB_ENV *dbenv, DB_MEM_CONFIG struct,
u_int32_t count); < / pre >
< p >
This method sets the number of objects to allocate and initialize
for a specified structure when an environment is created. Doing
this helps avoid memory contention after startup. Using this
method is optional; failure to use this method causes BDB to
allocate a minimal number of structures that will grow dynamically.
These structures are all allocated from the main environment
region. The amount of memory in this region can be set via the
< a class = "xref" href = "envset_memory_max.html" title = "DB_ENV->set_memory_max()" > DB_ENV-> set_memory_max()< / a >
method. If this method is not called then memory will be limited
to the initial settings or by the (deprecated) set maximum
interfaces.
< / p >
< p >
The database environment's initialization may also be configured
using the environment's < a href = "../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class = "olink" > DB_CONFIG< / a > file. The syntax of the entry
in that file is a single line with the string "set_memory_init",
one or more whitespace characters, followed by the struct
specification, more white space and the count to be allocated.
Because the < a href = "../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class = "olink" > DB_CONFIG< / a > file is read when the database environment
is opened, it will silently overrule configuration done before
that time.
< / p >
< p >
The < code class = "methodname" > DB_ENV-> set_memory_init()< / code > method must
be called prior to opening the database environment. It may be
called as often as needed to set the different configurations.
< / p >
< div class = "sect2" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h3 class = "title" > < a id = "id3714382" > < / a > Parameters< / h3 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< div class = "sect3" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h4 class = "title" > < a id = "id3716249" > < / a > struct< / h4 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
The < span class = "bold" > < strong > struct< / strong > < / span > parameter must be
set to one of the following:
< / p >
< div class = "itemizedlist" >
< ul type = "disc" >
< li >
< p > < a id = "envmem_DB_MEM_LOCK" > < / a >
< code class = "literal" > DB_MEM_LOCK< / code >
< / p >
< p >
Initialize locks. A thread uses this structure
to lock a page (or record for the QUEUE access
method) and hold it to the end of a transactions.
< / p >
< / li >
< li >
< p > < a id = "envmem_DB_MEM_LOCKOBJECT" > < / a >
< code class = "literal" > DB_MEM_LOCKOBJECT< / code >
< / p >
< p >
Initialize lock objects. For each page (or record) which
is locked in the system, a lock object will be allocated.
< / p >
< / li >
< li >
< p > < a id = "envmem_DB_MEM_LOCKER" > < / a >
< code class = "literal" > DB_MEM_LOCKER< / code >
< / p >
< p >
Initialize lockers. Each thread which is active in a
transactional environment will use a locker structure
either for each transaction which is active, or for each
non-transactional cursor that is active.
< / p >
< / li >
< li >
< p > < a id = "envmem_DB_MEM_LOGID" > < / a >
< code class = "literal" > DB_MEM_LOGID< / code >
< / p >
< p >
Initialize the log fileid structures. For each database handle
which is opened for writing in a transactional environment,
a log fileid structure is used.
< / p >
< / li >
< li >
< p > < a id = "envmem_DB_MEM_TRANSACTION" > < / a >
< code class = "literal" > DB_MEM_TRANSACTION< / code >
< / p >
< p >
Initialize transaction structures. Each active
transaction uses a transaction structure until it
either commits or aborts.
< / p >
< div class = "note" style = "margin-left: 0.5in; margin-right: 0.5in;" >
< h3 class = "title" > Note< / h3 >
< p >
Currently transaction structures are not
preallocated. This setting will be used to
preallocate memory and objects related to
transactions such as locker structures and
mutexes.
< / p >
< / div >
< / li >
< li >
< p > < a id = "envmem_DB_MEM_THREAD" > < / a >
< code class = "literal" > DB_MEM_THREAD< / code >
< / p >
< p >
Initialize thread identification structures. If thread
tracking is enabled then each active thread will use a
structure. Note that since a thread does not signal the
BDB library that it will no longer be making calls, unused
structures may accumulate until a cleanup is triggered either
using a high water mark or by running
< a class = "xref" href = "envfailchk.html" title = "DB_ENV->failchk()" > DB_ENV-> failchk()< / a > .
< / p >
< / li >
< / ul >
< / div >
< / div >
< div class = "sect3" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h4 class = "title" > < a id = "id3715910" > < / a > count< / h4 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
The < span class = "bold" > < strong > count< / strong > < / span > parameter
sets the number of specified objects to initialize.
< / p >
< p >
The < span class = "bold" > < strong > count< / strong > < / span > specified for
locks and lock objects should be at least 5 times the
number of lock table partitions. You can examine the
current number of lock table partitions configured for your
environment using the
< a class = "xref" href = "envget_lk_partitions.html" title = "DB_ENV->get_lk_partitions()" > DB_ENV-> get_lk_partitions()< / a >
method.
< / p >
< / div >
< / div >
< div class = "sect2" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h3 class = "title" > < a id = "id3715971" > < / a > Errors< / h3 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
The < code class = "methodname" > DB_ENV-> set_memory_init()< / code > < span >
< span >
method may fail and return one of the following non-zero errors:
< / span >
< / span >
< / p >
< div class = "sect3" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h4 class = "title" > < a id = "id3716323" > < / a > EINVAL< / h4 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
If the method was called after < a class = "xref" href = "envopen.html" title = "DB_ENV->open()" > DB_ENV-> open()< / a >
was called; or if an invalid flag value or parameter was specified.
< / p >
< / div >
< / div >
< div class = "sect2" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h3 class = "title" > < a id = "id3716281" > < / a > Class< / h3 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
< a class = "link" href = "env.html" title = "Chapter > DB_ENV< / a >
< / p >
< / div >
< div class = "sect2" lang = "en" xml:lang = "en" >
< div class = "titlepage" >
< div >
< div >
2011-12-20 00:07:10 +00:00
< h3 class = "title" > < a id = "id3716403" > < / a > See Also< / h3 >
2011-09-13 17:44:24 +00:00
< / div >
< / div >
< / div >
< p >
< a class = "xref" href = "env.html#envlist" title = "Database Environments and Related Methods" > Database Environments and Related Methods< / a >
< / p >
< / div >
< / div >
< div class = "navfooter" >
< hr / >
< table width = "100%" summary = "Navigation footer" >
< tr >
< td width = "40%" align = "left" > < a accesskey = "p" href = "envset_isalive.html" > Prev< / a > < / td >
< td width = "20%" align = "center" >
< a accesskey = "u" href = "env.html" > Up< / a >
< / td >
< td width = "40%" align = "right" > < a accesskey = "n" href = "envset_memory_max.html" > Next< / a > < / td >
< / tr >
< tr >
< td width = "40%" align = "left" valign = "top" > DB_ENV-> set_isalive() < / td >
< td width = "20%" align = "center" >
< a accesskey = "h" href = "index.html" > Home< / a >
< / td >
< td width = "40%" align = "right" valign = "top" > > set_memory_max()< / td >
< / tr >
< / table >
< / div >
< / body >
< / html >
