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791 строка
36 KiB
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<HTML>
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<HEAD>
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<TITLE>db_log</TITLE>
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</HEAD>
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<BODY BGCOLOR=white>
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<H1>db_log</H1>
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<HR SIZE=1 NOSHADE>
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<PRE>
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<!-- Manpage converted by man2html 3.0.1 -->
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<B>#include</B> <B><db.h></B>
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<B>int</B>
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<B>log</B>_<B>open(const</B> <B>char</B> <B>*dir,</B>
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<B>u</B>_<B>int32</B>_<B>t</B> <B>flags,</B> <B>int</B> <B>mode,</B> <B>DB</B>_<B>ENV</B> <B>*dbenv,</B> <B>DB</B>_<B>LOG</B> <B>**regionp);</B>
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<B>int</B>
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<B>log</B>_<B>close(DB</B>_<B>LOG</B> <B>*logp);</B>
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<B>int</B>
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<B>log</B>_<B>flush(DB</B>_<B>LOG</B> <B>*logp,</B> <B>const</B> <B>DB</B>_<B>LSN</B> <B>*lsn);</B>
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<B>int</B>
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<B>log</B>_<B>get(DB</B>_<B>LOG</B> <B>*logp,</B> <B>DB</B>_<B>LSN</B> <B>*lsn,</B> <B>DBT</B> <B>*data,</B> <B>u</B>_<B>int32</B>_<B>t</B> <B>flags);</B>
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<B>int</B>
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<B>log</B>_<B>compare(const</B> <B>DB</B>_<B>LSN</B> <B>*lsn0,</B> <B>const</B> <B>DB</B>_<B>LSN</B> <B>*lsn1);</B>
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<B>int</B>
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<B>log</B>_<B>file(DB</B>_<B>LOG</B> <B>*logp,</B> <B>const</B> <B>DB</B>_<B>LSN</B> <B>*lsn,</B> <B>char</B> <B>*namep,</B> <B>size</B>_<B>t</B> <B>len);</B>
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<B>int</B>
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<B>log</B>_<B>put(DB</B>_<B>LOG</B> <B>*logp,</B> <B>DB</B>_<B>LSN</B> <B>*lsn,</B> <B>const</B> <B>DBT</B> <B>*data,</B> <B>u</B>_<B>int32</B>_<B>t</B> <B>flags);</B>
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<B>int</B>
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<B>log</B>_<B>unlink(const</B> <B>char</B> <B>*dir,</B> <B>int</B> <B>force,</B> <B>DB</B>_<B>ENV</B> <B>*);</B>
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<B>int</B>
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<B>log</B>_<B>archive(DB</B>_<B>LOG</B> <B>*logp,</B>
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<B>char</B> <B>**list[],</B> <B>u</B>_<B>int32</B>_<B>t</B> <B>flags,</B> <B>void</B> <B>*(*db</B>_<B>malloc)(size</B>_<B>t));</B>
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<B>int</B>
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<B>log</B>_<B>register(DB</B>_<B>LOG</B> <B>*logp,</B>
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<B>const</B> <B>DB</B> <B>*dbp,</B> <B>const</B> <B>char</B> <B>*name,</B> <B>DBTYPE</B> <B>type,</B> <B>u</B>_<B>int32</B>_<B>t</B> <B>*fidp);</B>
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<B>int</B>
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<B>log</B>_<B>unregister(DB</B>_<B>LOG</B> <B>*logp,</B> <B>u</B>_<B>int32</B>_<B>t</B> <B>fid);</B>
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<B>int</B>
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<B>log</B>_<B>stat(DB</B>_<B>LOG</B> <B>*logp,</B> <B>DB</B>_<B>LOG</B>_<B>STAT</B> <B>**spp,</B> <B>void</B> <B>*(*db</B>_<B>malloc)(size</B>_<B>t));</B>
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</PRE>
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<H2>DESCRIPTION</H2><PRE>
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The DB library is a family of groups of functions that
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provides a modular programming interface to transactions
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and record-oriented file access. The library includes
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support for transactions, locking, logging and file page
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caching, as well as various indexed access methods. Many
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of the functional groups (e.g., the file page caching
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functions) are useful independent of the other DB
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functions, although some functional groups are explicitly
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based on other functional groups (e.g., transactions and
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logging). For a general description of the DB package,
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see <B><A HREF="db_intro.html">db_intro(3)</A></B>.
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This manual page describes the specific details of the log
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manager.
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These functions provide a general-purpose logging facility
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sufficient for transaction management. Logs can be shared
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by multiple processes.
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The DB transaction log is represented by a directory
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containing a set of files. The log is a record-oriented,
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append-only file, with records identified and accessed via
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DB_LSN's (database log sequence numbers).
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DB_LSN's are returned on each log_put operation, and only
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those DB_LSN's returned by log_put can later be used to
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retrieve records from the log.
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log_open
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The log_open function copies a pointer, to the log
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identified by the <B>directory</B> dir, into the memory location
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referenced by regionp.
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If the dbenv argument to log_open was initialized using
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db_appinit, dir is interpreted as described by
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<B><A HREF="db_appinit.html">db_appinit(3)</A></B>.
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Otherwise, if dir is not NULL, it is interpreted relative
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to the current working directory of the process. If dir
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is NULL, the following environment variables are checked
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in order: ``TMPDIR'', ``TEMP'', and ``TMP''. If one of
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them is set, log files are created relative to the
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directory it specifies. If none of them are set, the
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first possible one of the following directories is used:
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/var/tmp, /usr/tmp, /temp, /tmp, C:/temp and C:/tmp.
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All files associated with the log are created in this
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directory. This directory must already exist when
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log_open is called. If the log already exists, the
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process must have permission to read and write the
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existing files. If the log does not already exist, it is
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optionally created and initialized.
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If the log region is being created and log files are
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already present, the log files are ``recovered'' and
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subsequent log writes are appended to the end of the log.
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The log is stored in one or more files in the specified
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directory. Each file is named using the format
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log.NNNNN
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where ``NNNNN'' is the sequence number of the file within
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the log.
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The flags and mode arguments specify how files will be
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opened and/or created when they don't already exist. The
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flags value is specified by <B>or</B>'ing together one or more of
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the following values:
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DB_CREATE
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Create any underlying files, as necessary. If the
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files do not already exist and the DB_CREATE flag is
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not specified, the call will fail.
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DB_THREAD
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Cause the DB_LOG handle returned by the log_open
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function to be useable by multiple threads within a
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single address space, i.e., to be ``free-threaded''.
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All files created by the log subsystem are created with
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mode mode (as described in <B>chmod(2)</B>) and modified by the
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process' umask value at the time of creation (see
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<B>umask(2)</B>). The group ownership of created files is based
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on the system and directory defaults, and is not further
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specified by DB.
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The logging subsystem is configured based on the dbenv
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argument to log_open, which is a pointer to a structure of
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type DB_ENV (typedef'd in <db.h>). Applications will
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normally use the same DB_ENV structure (initialized by
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<B><A HREF="db_appinit.html">db_appinit(3)</A></B>), as an argument to all of the subsystems in
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the DB package.
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References to the DB_ENV structure are maintained by DB,
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so it may not be discarded until the last close function,
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corresponding to an open function for which it was an
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argument, has returned. In order to ensure compatibility
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with future releases of DB, all fields of the DB_ENV
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structure that are not explicitly set should be
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initialized to 0 before the first time the structure is
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used. Do this by declaring the structure external or
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static, or by calling the C library routine <B>bzero(3)</B> or
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<B>memset(3)</B>.
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The fields of the DB_ENV structure used by log_open are
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described below. If dbenv is NULL or any of its fields
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are set to 0, defaults appropriate for the system are used
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where possible.
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The following fields in the DB_ENV structure may be
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initialized before calling log_open:
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void *(*db_errcall)(char *db_errpfx, char *buffer);
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FILE *db_errfile;
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const char *db_errpfx;
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int db_verbose;
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The error fields of the DB_ENV behave as described
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for <B><A HREF="db_appinit.html">db_appinit(3)</A></B>.
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u_int32_t lg_max;
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The maximum size of a single file in the log.
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Because DB_LSN file offsets are unsigned 4-byte
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values, lg_max may not be larger than the maximum
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unsigned 4-byte value.
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If lg_max is 0, a default value is used.
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See the section "LOG FILE LIMITS" below, for further
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information.
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The log_open function returns the value of errno on
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failure and 0 on success.
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log_close
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The log_close function closes the log specified by the
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logp argument.
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In addition, if the dir argument to log_open was NULL and
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dbenv was not initialized using db_appinit, all files
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created for this shared region will be removed, as if
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log_unlink were called.
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When multiple threads are using the DB_LOG handle
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concurrently, only a single thread may call the log_close
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function.
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The log_close function returns the value of errno on
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failure and 0 on success.
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log_flush
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The log_flush function guarantees that all log records
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whose LSNs are less than or equal to the lsn parameter
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have been written to disk. If lsn is NULL, all records in
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the log are flushed.
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The log_flush function returns the value of errno on
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failure and 0 on success.
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log_get
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The log_get function implements a cursor inside of the
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log, retrieving records from the log according to the lsn
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and flags parameters.
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The data field of the data structure is set to the record
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retrieved and the size field indicates the number of bytes
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in the record. See <B><A HREF="db_dbt.html">db_dbt(3)</A></B> for a description of other
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fields in the data structure. <B>When</B> <B>multiple</B> <B>threads</B> <B>are</B>
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<B>using</B> <B>the</B> <B>returned</B> <B>DB</B>_<B>LOG</B> <B>handle</B> <B>concurrently,</B> <B>either</B> <B>the</B>
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<B>DB</B>_<B>DBT</B>_<B>MALLOC</B> <B>or</B> <B>DB</B>_<B>DBT</B>_<B>USERMEM</B> <B>flags</B> <B>must</B> <B>be</B> <B>specified</B>
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<B>for</B> <B>any</B> <B>DBT</B> <B>used</B> <B>for</B> <B>data</B> <B>retrieval.</B>
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The flags parameter must be set to exactly one of the
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following values:
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DB_CHECKPOINT
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The last record written with the DB_CHECKPOINT flag
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specified to the log_put function is returned in the
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data argument. The lsn argument is overwritten with
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the DB_LSN of the record returned. If no record has
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been previously written with the DB_CHECKPOINT flag
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specified, the first record in the log is returned.
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If the log is empty the log_get function will return
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DB_NOTFOUND.
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DB_FIRST
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The first record from any of the log files found in
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the log directory is returned in the data argument.
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The lsn argument is overwritten with the DB_LSN of
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the record returned.
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If the log is empty the log_get function will return
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DB_NOTFOUND.
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DB_LAST
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The last record in the log is returned in the data
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argument. The lsn argument is overwritten with the
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DB_LSN of the record returned.
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If the log is empty, the log_get function will return
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DB_NOTFOUND.
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DB_NEXT
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The current log position is advanced to the next
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record in the log and that record is returned in the
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data argument. The lsn argument is overwritten with
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the DB_LSN of the record returned.
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If the pointer has not been initialized via DB_FIRST,
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DB_LAST, DB_SET, DB_NEXT, or DB_PREV, log_get will
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return the first record in the log. If the last log
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record has already been returned or the log is empty,
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the log_get function will return DB_NOTFOUND.
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If the log was opened with the DB_THREAD flag set,
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calls to log_get with the DB_NEXT flag set will
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return EINVAL.
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DB_PREV
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The current log position is moved to the previous
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record in the log and that record is returned in the
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data argument. The lsn argument is overwritten with
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the DB_LSN of the record returned.
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If the pointer has not been initialized via DB_FIRST,
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DB_LAST, DB_SET, DB_NEXT, or DB_PREV, log_get will
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return the last record in the log. If the first log
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record has already been returned or the log is empty,
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the log_get function will return DB_NOTFOUND.
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If the log was opened with the DB_THREAD flag set,
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calls to log_get with the DB_PREV flag set will
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return EINVAL.
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DB_CURRENT
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Return the log record currently referenced by the
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log.
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If the log pointer has not been initialized via
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DB_FIRST, DB_LAST, DB_SET, DB_NEXT, or DB_PREV, or if
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the log was opened with the DB_THREAD flag set,
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log_get will return EINVAL.
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DB_SET
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Retrieve the record specified by the lsn argument.
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If the specified DB_LSN is invalid (e.g., does not
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appear in the log) log_get will return EINVAL.
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Otherwise, the log_get function returns the value of errno
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on failure and 0 on success.
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log_compare
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The log_compare function allows the caller to compare two
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DB_LSN's. Log_compare returns 0 if the two DB_LSN's are
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equal, 1 if lsn0 is greater than lsn1, and -1 if lsn0 is
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less than lsn1.
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log_file
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The log_file function maps DB_LSN's to file names. The
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log_file function copies the name of the file containing
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the record named by lsn into the memory location
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referenced by namep. (This mapping of DB_LSN to file is
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needed for database administration. For example, a
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transaction manager typically records the earliest DB_LSN
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needed for restart, and the database administrator may
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want to archive log files to tape when they contain only
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DB_LSN's before the earliest one needed for restart.)
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The len argument is the length of the namep buffer in
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bytes. If namep is too short to hold the file name,
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log_file will return ENOMEM. Note, as described above,
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log file names are quite short, on the order of 10
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characters.
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The log_file function returns the value of errno on
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failure and 0 on success.
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log_put
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The log_put function appends records to the log. The
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DB_LSN of the put record is returned in the lsn parameter.
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The flags parameter may be set to one of the following
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values:
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DB_CHECKPOINT
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The log should write a checkpoint record, recording
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any information necessary to make the log structures
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recoverable after a crash.
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DB_CURLSN
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The DB_LSN of the next record to be put is returned
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in the lsn parameter.
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DB_FLUSH
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The log is forced to disk after this record is
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written, guaranteeing that all records with DB_LSNs
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less than or equal to the one being put are on disk
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before this function returns (this function is most
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often used for a transaction commit, see <B><A HREF="db_txn.html">db_txn(3)</A></B>).
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The caller is responsible for providing any necessary
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structure to data. (For example, in a write-ahead logging
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protocol, the application must understand what part of
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data is an operation code, what part is redo information,
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and what part is undo information. In addition, most
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transaction managers will store in data the DB_LSN of the
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previous log record for the same transaction, to support
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chaining back through the transaction's log records during
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undo.)
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The log_put function returns the value of errno on failure
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and 0 on success.
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log_unlink
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The log_unlink function destroys the log region identified
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by the directory dir, removing all files used to implement
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the log region. (The log files themselves and the
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directory dir are not removed.) If there are processes
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that have called log_open without calling log_close (i.e.,
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there are processes currently using the log region),
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log_unlink will fail without further action, unless the
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force flag is set, in which case log_unlink will attempt
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to remove the log region files regardless of any processes
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still using the log region.
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The result of attempting to forcibly destroy the region
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when a process has the region open is unspecified.
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Processes using a shared memory region maintain an open
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file descriptor for it. On UNIX systems, the region
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removal should succeed and processes that have already
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joined the region should continue to run in the region
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without change, however processes attempting to join the
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log region will either fail or attempt to create a new
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region. On other systems, e.g., WNT, where the <B>unlink(2)</B>
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system call will fail if any process has an open file
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descriptor for the file, the region removal will fail.
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In the case of catastrophic or system failure, database
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recovery must be performed (see <B><A HREF="db_recover.html">db_recover(1)</A></B> or the
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DB_RECOVER and DB_RECOVER_FATAL flags to <B><A HREF="db_appinit.html">db_appinit(3)</A></B>).
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Alternatively, if recovery is not required because no
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database state is maintained across failures, it is
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possible to clean up a log region by removing all of the
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files in the directory specified to the log_open function,
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as log region files are never created in any directory
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other than the one specified to log_open. Note, however,
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that this has the potential to remove files created by the
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other DB subsystems in this database environment.
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The log_unlink function returns the value of errno on
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failure and 0 on success.
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log_archive
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The log_archive function creates a NULL-terminated array
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of log or database file names and copies a pointer to them
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into the user-specified memory location list.
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By default, log_archive returns the names of all of the
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log files that are no longer in use (e.g., no longer
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involved in active transactions), and that may be archived
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for catastrophic recovery and then removed from the
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system. If there were no file names to return, list will
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be set to NULL.
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Arrays of log file names are created in allocated memory.
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If db_malloc is non-NULL, it is called to allocate the
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memory, otherwise, the library function <B>malloc(3)</B> is used.
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The function db_malloc must match the calling conventions
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of the <B>malloc(3)</B> library routine. Regardless, the caller
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is responsible for deallocating the returned memory. To
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deallocate the returned memory, free each returned memory
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pointer; pointers inside the memory do not need to be
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individually freed.
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The flags argument is specified by <B>or</B>'ing together one or
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more of the following values:
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|
|
|
DB_ARCH_ABS
|
|
All pathnames are returned as absolute pathnames,
|
|
instead of relative to the database home directory.
|
|
|
|
DB_ARCH_DATA
|
|
Return the database files that need to be archived in
|
|
order to recover the database from catastrophic
|
|
failure. If any of the database files have not been
|
|
accessed during the lifetime of the current log
|
|
files, log_archive will not include them in this
|
|
list. It is also possible that some of the files
|
|
referenced in the log have since been deleted from
|
|
the system.
|
|
|
|
DB_ARCH_LOG
|
|
Return all the log file names regardless of whether
|
|
or not they are in use.
|
|
|
|
The DB_ARCH_DATA and DB_ARCH_LOG flags are mutually
|
|
exclusive.
|
|
|
|
The log_archive function returns the value of errno on
|
|
failure and 0 on success.
|
|
|
|
The log_archive function is the underlying function used
|
|
by the <B><A HREF="db_archive.html">db_archive(1)</A></B> utility. See the source code for the
|
|
db_archive utility for an example of using log_archive in
|
|
a UNIX environment. See the <B><A HREF="db_archive.html">db_archive(1)</A></B> manual page for
|
|
more information on database archival procedures.
|
|
|
|
log_register
|
|
The log_register function registers a file name with the
|
|
log manager and copies a file identification number into
|
|
the memory location referenced by fidp. This file
|
|
identification number should be used in all subsequent log
|
|
messages that refer to operations on this file. The log
|
|
manager records all file name to file identification
|
|
number mappings at each checkpoint so that a recovery
|
|
process can identify the file to which a record in the log
|
|
refers.
|
|
|
|
The log_register function is called when an access method
|
|
registers the open of a file. The dbp parameter should be
|
|
a pointer to the DB structure which is being returned by
|
|
the access method.
|
|
|
|
The type parameter should be one of the DB types specified
|
|
in <B><A HREF="db_open.html">db_open(3)</A></B>, e.g., DB_HASH.
|
|
|
|
The log_register function returns the value of errno on
|
|
failure and 0 on success.
|
|
|
|
log_unregister
|
|
The log_unregister function disassociates the file name to
|
|
file identification number mapping for the file
|
|
identification number specified by the fid parameter. The
|
|
file identification number may then be reused.
|
|
|
|
The log_unregister function returns the value of errno on
|
|
failure and 0 on success.
|
|
|
|
log_stat
|
|
The log_stat function creates a statistical structure and
|
|
copies a pointer to it into the user-specified memory
|
|
location.
|
|
|
|
Statistical structure are created in allocated memory. If
|
|
db_malloc is non-NULL, it is called to allocate the
|
|
memory, otherwise, the library function <B>malloc(3)</B> is used.
|
|
The function db_malloc must match the calling conventions
|
|
of the <B>malloc(3)</B> library routine. Regardless, the caller
|
|
is responsible for deallocating the returned memory. To
|
|
deallocate the returned memory, free each returned memory
|
|
pointer; pointers inside the memory do not need to be
|
|
individually freed.
|
|
|
|
The log region statistics are stored in a structure of
|
|
type DB_LOG_STAT (typedef'd in <db.h>). The following
|
|
DB_LOG_STAT fields will be filled in:
|
|
|
|
u_int32_t st_magic;
|
|
The magic number that identifies a file as a log
|
|
file.
|
|
u_int32_t st_version;
|
|
The version of the log file type.
|
|
u_int32_t st_refcnt;
|
|
The number of references to the region.
|
|
u_int32_t st_regsize;
|
|
The size of the region.
|
|
int st_mode;
|
|
The mode of any created log files.
|
|
u_int32_t st_lg_max;
|
|
The maximum size of any individual file comprising
|
|
the log.
|
|
u_int32_t st_w_mbytes;
|
|
The number of megabytes written to this log.
|
|
u_int32_t st_w_bytes;
|
|
The number of bytes over and above st_w_mbytes
|
|
written to this log.
|
|
u_int32_t st_wc_mbytes;
|
|
The number of megabytes written to this log since the
|
|
last checkpoint.
|
|
u_int32_t st_wc_bytes;
|
|
The number of bytes over and above st_wc_mbytes
|
|
written to this log since the last checkpoint.
|
|
u_int32_t st_cur_file;
|
|
The current log file number.
|
|
u_int32_t st_cur_offset;
|
|
The byte offset in the current log file.
|
|
u_int32_t st_region_wait;
|
|
The number of times that a thread of control was
|
|
forced to wait before obtaining the region lock.
|
|
u_int32_t st_region_nowait;
|
|
The number of times that a thread of control was able
|
|
to obtain the region lock without waiting.
|
|
|
|
|
|
</PRE>
|
|
<H2>LOG FILE LIMITS</H2><PRE>
|
|
Log file sizes impose a time limit on the length of time a
|
|
database may be accessed under transaction protection,
|
|
before it needs to be dumped and reloaded (see <B><A HREF="db_dump.html">db_dump(3)</A></B>
|
|
and <B><A HREF="db_load.html">db_load(3)</A></B>). Unfortunately, the limits are
|
|
potentially difficult to calculate.
|
|
|
|
The log file name consists of "log." followed by 5 digits,
|
|
resulting in a maximum of 99,999 log files. Consider an
|
|
application performing 600 transactions per second, for 15
|
|
hours a day, logged into 10Mb log files, where each
|
|
transaction is logging approximately 100 bytes of data.
|
|
The calculation:
|
|
|
|
(10 * 2^20 * 99999) /
|
|
(600 * 60 * 60 * 15 * 100) = 323.63
|
|
|
|
indicates that the system will run out of log file space
|
|
in roughly 324 days. If we increase the maximum size of
|
|
the files from 10Mb to 100Mb, the same calculation
|
|
indicates that the application will run out of log file
|
|
space in roughly 9 years.
|
|
|
|
There is no way to reset the log file name space in
|
|
Berkeley DB. If your application is reaching the end of
|
|
its log file name space, you should:
|
|
|
|
1. Archive your databases as if to prepare for
|
|
catastrophic failure (see <B><A HREF="db_archive.html">db_archive(1)</A></B> for more
|
|
information).
|
|
|
|
2. Dump and re-load <B>all</B> your databases (see <B><A HREF="db_dump.html">db_dump(1)</A></B>
|
|
and <B><A HREF="db_load.html">db_load(1)</A></B> for more information).
|
|
|
|
3. Remove all of the log files from the database
|
|
environment (see <B><A HREF="db_archive.html">db_archive(1)</A></B> for more information).
|
|
|
|
4. Restart your applications.
|
|
|
|
|
|
</PRE>
|
|
<H2>ENVIRONMENT VARIABLES</H2><PRE>
|
|
The following environment variables affect the execution
|
|
of db_log:
|
|
|
|
DB_HOME
|
|
If the dbenv argument to log_open was initialized
|
|
using db_appinit, the environment variable DB_HOME
|
|
may be used as the path of the database home for the
|
|
interpretation of the dir argument to log_open, as
|
|
described in <B><A HREF="db_appinit.html">db_appinit(3)</A></B>. Specifically, log_open
|
|
is affected by the configuration string value of
|
|
DB_LOG_DIR.
|
|
|
|
TMPDIR
|
|
If the dbenv argument to log_open was NULL or not
|
|
initialized using db_appinit, the environment
|
|
variable TMPDIR may be used as the directory in which
|
|
to create the log, as described in the log_open
|
|
section above.
|
|
|
|
|
|
</PRE>
|
|
<H2>ERRORS</H2><PRE>
|
|
The log_open function may fail and return errno for any of
|
|
the errors specified for the following DB and library
|
|
functions: <B>atoi(3)</B>, <B>close(2)</B>, <B><A HREF="db_appinit.html">db_version(3)</A></B>, <B>fcntl(2)</B>,
|
|
<B>fflush(3)</B>, <B><A HREF="db_log.html">log_close(3)</A></B>, <B><A HREF="db_log.html">log_unlink(3)</A></B>, <B>lseek(2)</B>,
|
|
<B>malloc(3)</B>, <B>memcpy(3)</B>, <B>memset(3)</B>, <B>mmap(2)</B>, <B>munmap(2)</B>,
|
|
<B>open(2)</B>, <B>opendir(3)</B>, <B>read(2)</B>, <B>readdir(3)</B>, <B>realloc(3)</B>,
|
|
<B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strchr(3)</B>,
|
|
<B>strcpy(3)</B>, <B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, <B>strncmp(3)</B>,
|
|
<B>unlink(2)</B>, and <B>write(2)</B>.
|
|
|
|
In addition, the log_open function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EAGAIN]
|
|
The shared memory region was locked and (repeatedly)
|
|
unavailable.
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The DB_THREAD flag was specified and spinlocks are
|
|
not implemented for this architecture.
|
|
|
|
The specified file size was too large.
|
|
|
|
The log_close function may fail and return errno for any
|
|
of the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>munmap(2)</B>, and
|
|
<B>strerror(3)</B>.
|
|
|
|
The log_flush function may fail and return errno for any
|
|
of the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>fsync(2)</B>,
|
|
<B>lseek(2)</B>, <B>malloc(3)</B>, <B>memcpy(3)</B>, <B>memset(3)</B>, <B>open(2)</B>,
|
|
<B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strcpy(3)</B>,
|
|
<B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, <B>unlink(2)</B>, and
|
|
<B>write(2)</B>.
|
|
|
|
In addition, the log_flush function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The log_get function may fail and return errno for any of
|
|
the errors specified for the following DB and library
|
|
functions: <B>atoi(3)</B>, <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>,
|
|
<B>lseek(2)</B>, <B>malloc(3)</B>, <B>memcpy(3)</B>, <B>memset(3)</B>, <B>open(2)</B>,
|
|
<B>opendir(3)</B>, <B>read(2)</B>, <B>readdir(3)</B>, <B>realloc(3)</B>,
|
|
<B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strchr(3)</B>,
|
|
<B>strcpy(3)</B>, <B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, <B>strncmp(3)</B>,
|
|
and <B>unlink(2)</B>.
|
|
|
|
In addition, the log_get function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The DB_FIRST flag was specified and no log files were
|
|
found.
|
|
|
|
The log_file function may fail and return errno for any of
|
|
the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>malloc(3)</B>,
|
|
<B>memcpy(3)</B>, <B>memset(3)</B>, <B>open(2)</B>, <B>sigfillset(3)</B>,
|
|
<B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strcpy(3)</B>, <B>strdup(3)</B>,
|
|
<B>strerror(3)</B>, <B>strlen(3)</B>, and <B>unlink(2)</B>.
|
|
|
|
In addition, the log_file function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[ENOMEM]
|
|
The supplied buffer was too small to hold the log
|
|
file name.
|
|
|
|
The log_put function may fail and return errno for any of
|
|
the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>fsync(2)</B>,
|
|
<B>lseek(2)</B>, <B>malloc(3)</B>, <B>memcpy(3)</B>, <B>memset(3)</B>, <B>open(2)</B>,
|
|
<B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strcpy(3)</B>,
|
|
<B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, <B>time(3)</B>, <B>unlink(2)</B>, and
|
|
<B>write(2)</B>.
|
|
|
|
In addition, the log_put function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The record to be logged is larger than the maximum
|
|
log record.
|
|
|
|
The log_unlink function may fail and return errno for any
|
|
of the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>malloc(3)</B>,
|
|
<B>memcpy(3)</B>, <B>memset(3)</B>, <B>mmap(2)</B>, <B>munmap(2)</B>, <B>open(2)</B>,
|
|
<B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strcpy(3)</B>,
|
|
<B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, and <B>unlink(2)</B>.
|
|
|
|
In addition, the log_unlink function may fail and return
|
|
errno for the following conditions:
|
|
[EBUSY]
|
|
The shared memory region was in use and the force
|
|
flag was not set.
|
|
|
|
The log_archive function may fail and return errno for any
|
|
of the errors specified for the following DB and library
|
|
functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>, <B>getcwd(3)</B>,
|
|
<B><A HREF="db_log.html">log_compare(3)</A></B>, <B><A HREF="db_log.html">log_get(3)</A></B>, <B>malloc(3)</B>, <B>memcpy(3)</B>,
|
|
<B>memset(3)</B>, <B>open(2)</B>, <B>qsort(3)</B>, <B>realloc(3)</B>, <B>sigfillset(3)</B>,
|
|
<B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strchr(3)</B>, <B>strcmp(3)</B>, <B>strcpy(3)</B>,
|
|
<B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, and <B>unlink(2)</B>.
|
|
|
|
In addition, the log_archive function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The log was corrupted.
|
|
|
|
The log_register function may fail and return errno for
|
|
any of the errors specified for the following DB and
|
|
library functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>,
|
|
<B>fsync(2)</B>, <B>lseek(2)</B>, <B>malloc(3)</B>, <B>memcmp(3)</B>, <B>memcpy(3)</B>,
|
|
<B>memset(3)</B>, <B>open(2)</B>, <B>realloc(3)</B>, <B>sigfillset(3)</B>,
|
|
<B>sigprocmask(2)</B>, <B>stat(2)</B>, <B>strcpy(3)</B>, <B>strdup(3)</B>,
|
|
<B>strerror(3)</B>, <B>strlen(3)</B>, <B>time(3)</B>, <B>unlink(2)</B>, and <B>write(2)</B>.
|
|
|
|
In addition, the log_register function may fail and return
|
|
errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The log_unregister function may fail and return errno for
|
|
any of the errors specified for the following DB and
|
|
library functions: <B>close(2)</B>, <B>fcntl(2)</B>, <B>fflush(3)</B>,
|
|
<B>fsync(2)</B>, <B>lseek(2)</B>, <B>malloc(3)</B>, <B>memcpy(3)</B>, <B>memset(3)</B>,
|
|
<B>open(2)</B>, <B>sigfillset(3)</B>, <B>sigprocmask(2)</B>, <B>stat(2)</B>,
|
|
<B>strcpy(3)</B>, <B>strdup(3)</B>, <B>strerror(3)</B>, <B>strlen(3)</B>, <B>time(3)</B>,
|
|
<B>unlink(2)</B>, and <B>write(2)</B>.
|
|
|
|
In addition, the log_unregister function may fail and
|
|
return errno for the following conditions:
|
|
|
|
[EINVAL]
|
|
An invalid flag value or parameter was specified.
|
|
|
|
The log_stat function may fail and return errno for any of
|
|
the errors specified for the following DB and library
|
|
functions: <B>fcntl(2)</B>, and <B>malloc(3)</B>.
|
|
|
|
|
|
</PRE>
|
|
<H2>BUGS</H2><PRE>
|
|
The log files are not machine architecture independent.
|
|
Specifically, log file metadata is not stored in a fixed
|
|
byte order.
|
|
|
|
|
|
</PRE>
|
|
<H2>SEE ALSO</H2><PRE>
|
|
<B><A HREF="db_archive.html">db_archive(1)</A></B>, <B><A HREF="db_checkpoint.html">db_checkpoint(1)</A></B>, <B><A HREF="db_deadlock.html">db_deadlock(1)</A></B>, <B><A HREF="db_dump.html">db_dump(1)</A></B>,
|
|
<B><A HREF="db_load.html">db_load(1)</A></B>, <B><A HREF="db_recover.html">db_recover(1)</A></B>, <B><A HREF="db_stat.html">db_stat(1)</A></B>, <B><A HREF="db_intro.html">db_intro(3)</A></B>,
|
|
<B><A HREF="db_appinit.html">db_appinit(3)</A></B>, <B><A HREF="db_cursor.html">db_cursor(3)</A></B>, <B><A HREF="db_dbm.html">db_dbm(3)</A></B>, <B><A HREF="db_internal.html">db_internal(3)</A></B>,
|
|
<B><A HREF="db_lock.html">db_lock(3)</A></B>, <B><A HREF="db_log.html">db_log(3)</A></B>, <B><A HREF="db_mpool.html">db_mpool(3)</A></B>, <B><A HREF="db_open.html">db_open(3)</A></B>, <B><A HREF="db_thread.html">db_thread(3)</A></B>,
|
|
<B><A HREF="db_txn.html">db_txn(3)</A></B>
|
|
|
|
</PRE>
|
|
<HR SIZE=1 NOSHADE>
|
|
<ADDRESS>
|
|
Man(1) output converted with
|
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<a href="http://www.oac.uci.edu/indiv/ehood/man2html.html">man2html</a>
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</ADDRESS>
|
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</BODY>
|
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</HTML>
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