--enable-debug build with debugging symbols (-g)
--enable-profiling build with profiling enabled
--enable-dtrace build with DTrace support
- --disable-segmented-files disable data file segmentation (requires largefile support)
--enable-depend turn on automatic dependency tracking
--enable-cassert enable assertion checks (for debugging)
--enable-thread-safety make client libraries thread-safe
--with-includes=DIRS look for additional header files in DIRS
--with-libraries=DIRS look for additional libraries in DIRS
--with-libs=DIRS alternative spelling of --with-libraries
- --with-pgport=PORTNUM change default port number [5432]
+ --with-pgport=PORTNUM set default port number [5432]
+ --with-blocksize=BLOCKSIZE set block size in kB [8]
+ --with-segsize=SEGSIZE set segment size in GB [1]
--with-tcl build Tcl modules (PL/Tcl)
--with-tclconfig=DIR tclConfig.sh is in DIR
--with-perl build Perl modules (PL/Perl)
#
-# Data file segmentation
+# Block size
#
+{ echo "$as_me:$LINENO: checking for block size" >&5
+echo $ECHO_N "checking for block size... $ECHO_C" >&6; }
-pgac_args="$pgac_args enable_segmented_files"
+pgac_args="$pgac_args with_blocksize"
-# Check whether --enable-segmented-files was given.
-if test "${enable_segmented_files+set}" = set; then
- enableval=$enable_segmented_files;
- case $enableval in
+
+# Check whether --with-blocksize was given.
+if test "${with_blocksize+set}" = set; then
+ withval=$with_blocksize;
+ case $withval in
yes)
- :
+ { { echo "$as_me:$LINENO: error: argument required for --with-blocksize option" >&5
+echo "$as_me: error: argument required for --with-blocksize option" >&2;}
+ { (exit 1); exit 1; }; }
;;
no)
- :
+ { { echo "$as_me:$LINENO: error: argument required for --with-blocksize option" >&5
+echo "$as_me: error: argument required for --with-blocksize option" >&2;}
+ { (exit 1); exit 1; }; }
;;
*)
- { { echo "$as_me:$LINENO: error: no argument expected for --enable-segmented-files option" >&5
-echo "$as_me: error: no argument expected for --enable-segmented-files option" >&2;}
- { (exit 1); exit 1; }; }
+ blocksize=$withval
;;
esac
else
- enable_segmented_files=yes
+ blocksize=8
+fi
+
+
+case ${blocksize} in
+ 1) BLCKSZ=1024;;
+ 2) BLCKSZ=2048;;
+ 4) BLCKSZ=4096;;
+ 8) BLCKSZ=8192;;
+ 16) BLCKSZ=16384;;
+ 32) BLCKSZ=32768;;
+ *) { { echo "$as_me:$LINENO: error: Invalid block size. Allowed values are 1,2,4,8,16,32." >&5
+echo "$as_me: error: Invalid block size. Allowed values are 1,2,4,8,16,32." >&2;}
+ { (exit 1); exit 1; }; }
+esac
+{ echo "$as_me:$LINENO: result: ${blocksize}kB" >&5
+echo "${ECHO_T}${blocksize}kB" >&6; }
+
+
+cat >>confdefs.h <<_ACEOF
+#define BLCKSZ ${BLCKSZ}
+_ACEOF
+
+
+#
+# File segment size
+#
+{ echo "$as_me:$LINENO: checking for segment size" >&5
+echo $ECHO_N "checking for segment size... $ECHO_C" >&6; }
+
+pgac_args="$pgac_args with_segsize"
+
+# Check whether --with-segsize was given.
+if test "${with_segsize+set}" = set; then
+ withval=$with_segsize;
+ case $withval in
+ yes)
+ { { echo "$as_me:$LINENO: error: argument required for --with-segsize option" >&5
+echo "$as_me: error: argument required for --with-segsize option" >&2;}
+ { (exit 1); exit 1; }; }
+ ;;
+ no)
+ { { echo "$as_me:$LINENO: error: argument required for --with-segsize option" >&5
+echo "$as_me: error: argument required for --with-segsize option" >&2;}
+ { (exit 1); exit 1; }; }
+ ;;
+ *)
+ segsize=$withval
+ ;;
+ esac
+
+else
+ segsize=1
fi
+# this expression is set up to avoid unnecessary integer overflow
+RELSEG_SIZE=`expr '(' 1024 '*' ${segsize} / ${blocksize} ')' '*' 1024`
+test $? -eq 0 || exit 1
+{ echo "$as_me:$LINENO: result: ${segsize}GB" >&5
+echo "${ECHO_T}${segsize}GB" >&6; }
+
+
+cat >>confdefs.h <<_ACEOF
+#define RELSEG_SIZE ${RELSEG_SIZE}
+_ACEOF
+
#
# C compiler
-if test "$ac_cv_sizeof_off_t" -lt 8 -o "$enable_segmented_files" = "yes"; then
-
-cat >>confdefs.h <<\_ACEOF
-#define USE_SEGMENTED_FILES 1
-_ACEOF
-
+# If we don't have largefile support, can't handle segsize >= 2GB.
+if test "$ac_cv_sizeof_off_t" -lt 8 -a "$segsize" != "1"; then
+ { { echo "$as_me:$LINENO: error: Large file support is not enabled. Segment size cannot be larger than 1GB." >&5
+echo "$as_me: error: Large file support is not enabled. Segment size cannot be larger than 1GB." >&2;}
+ { (exit 1); exit 1; }; }
fi
# SunOS doesn't handle negative byte comparisons properly with +/- return
dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.557 2008/04/28 22:47:03 tgl Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.558 2008/05/02 01:08:26 tgl Exp $
dnl
dnl Developers, please strive to achieve this order:
dnl
# Default port number (--with-pgport), default 5432
#
AC_MSG_CHECKING([for default port number])
-PGAC_ARG_REQ(with, pgport, [ --with-pgport=PORTNUM change default port number [[5432]]],
+PGAC_ARG_REQ(with, pgport, [ --with-pgport=PORTNUM set default port number [[5432]]],
[default_port=$withval],
[default_port=5432])
AC_MSG_RESULT([$default_port])
AC_SUBST(enable_dtrace)
#
-# Data file segmentation
-#
-PGAC_ARG_BOOL(enable, segmented-files, yes,
- [ --disable-segmented-files disable data file segmentation (requires largefile support)])
+# Block size
+#
+AC_MSG_CHECKING([for block size])
+PGAC_ARG_REQ(with, blocksize, [ --with-blocksize=BLOCKSIZE set block size in kB [[8]]],
+ [blocksize=$withval],
+ [blocksize=8])
+case ${blocksize} in
+ 1) BLCKSZ=1024;;
+ 2) BLCKSZ=2048;;
+ 4) BLCKSZ=4096;;
+ 8) BLCKSZ=8192;;
+ 16) BLCKSZ=16384;;
+ 32) BLCKSZ=32768;;
+ *) AC_MSG_ERROR([Invalid block size. Allowed values are 1,2,4,8,16,32.])
+esac
+AC_MSG_RESULT([${blocksize}kB])
+
+AC_DEFINE_UNQUOTED([BLCKSZ], ${BLCKSZ}, [
+ Size of a disk block --- this also limits the size of a tuple. You
+ can set it bigger if you need bigger tuples (although TOAST should
+ reduce the need to have large tuples, since fields can be spread
+ across multiple tuples).
+
+ BLCKSZ must be a power of 2. The maximum possible value of BLCKSZ
+ is currently 2^15 (32768). This is determined by the 15-bit widths
+ of the lp_off and lp_len fields in ItemIdData (see
+ include/storage/itemid.h).
+
+ Changing BLCKSZ requires an initdb.
+])
+
+#
+# File segment size
+#
+AC_MSG_CHECKING([for segment size])
+PGAC_ARG_REQ(with, segsize, [ --with-segsize=SEGSIZE set segment size in GB [[1]]],
+ [segsize=$withval],
+ [segsize=1])
+# this expression is set up to avoid unnecessary integer overflow
+RELSEG_SIZE=`expr '(' 1024 '*' ${segsize} / ${blocksize} ')' '*' 1024`
+test $? -eq 0 || exit 1
+AC_MSG_RESULT([${segsize}GB])
+
+AC_DEFINE_UNQUOTED([RELSEG_SIZE], ${RELSEG_SIZE}, [
+ RELSEG_SIZE is the maximum number of blocks allowed in one disk file.
+ Thus, the maximum size of a single file is RELSEG_SIZE * BLCKSZ;
+ relations bigger than that are divided into multiple files.
+
+ RELSEG_SIZE * BLCKSZ must be less than your OS' limit on file size.
+ This is often 2 GB or 4GB in a 32-bit operating system, unless you
+ have large file support enabled. By default, we make the limit 1 GB
+ to avoid any possible integer-overflow problems within the OS.
+ A limit smaller than necessary only means we divide a large
+ relation into more chunks than necessary, so it seems best to err
+ in the direction of a small limit.
+
+ A power-of-2 value is recommended to save a few cycles in md.c,
+ but is not absolutely required.
+
+ Changing RELSEG_SIZE requires an initdb.
+])
#
# C compiler
# Check for largefile support (must be after AC_SYS_LARGEFILE)
AC_CHECK_SIZEOF([off_t])
-if test "$ac_cv_sizeof_off_t" -lt 8 -o "$enable_segmented_files" = "yes"; then
- AC_DEFINE([USE_SEGMENTED_FILES], 1, [Define to split data files into 1GB segments.])
+# If we don't have largefile support, can't handle segsize >= 2GB.
+if test "$ac_cv_sizeof_off_t" -lt 8 -a "$segsize" != "1"; then
+ AC_MSG_ERROR([Large file support is not enabled. Segment size cannot be larger than 1GB.])
fi
# SunOS doesn't handle negative byte comparisons properly with +/- return
-<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.307 2008/04/21 00:26:44 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.308 2008/05/02 01:08:26 tgl Exp $ -->
<chapter id="installation">
<title><![%standalone-include[<productname>PostgreSQL</>]]>
</varlistentry>
<varlistentry>
- <term><option>--disable-segmented-files</option></term>
+ <term><option>--with-segsize=<replaceable>SEGSIZE</replaceable></option></term>
<listitem>
<para>
- Store large tables as single operating-system files, rather than
- dividing them into 1GB segments as is the default. This option
- is ignored unless the operating system has <quote>largefile</>
- support (which most do, nowadays). It can be helpful to reduce
- the number of file descriptors consumed when working with very
- large tables.
+ Set the <firstterm>segment size</>, in gigabytes. Large tables are
+ divided into multiple operating-system files, each of size equal
+ to the segment size. This avoids problems with file size limits
+ that exist on many platforms. The default segment size, 1 gigabyte,
+ is safe on all supported platforms. If your operating system has
+ <quote>largefile</> support (which most do, nowadays), you can use
+ a larger segment size. This can be helpful to reduce the number of
+ file descriptors consumed when working with very large tables.
+ But be careful not to select a value larger than is supported
+ by your platform and the filesystem(s) you intend to use. Other
+ tools you might wish to use, such as <application>tar</>, could
+ also set limits on the usable file size.
+ It is recommended, though not absolutely required, that this value
+ be a power of 2.
+ Note that changing this value requires an initdb.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--with-blocksize=<replaceable>BLOCKSIZE</replaceable></option></term>
+ <listitem>
+ <para>
+ Set the <firstterm>block size</>, in kilobytes. This is the unit
+ of storage and I/O within tables. The default, 8 kilobytes,
+ is suitable for most situations; but other values may be useful
+ in special cases.
+ The value must be a power of 2 between 1 and 32 (kilobytes).
+ Note that changing this value requires an initdb.
</para>
</listitem>
</varlistentry>
-<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.22 2008/03/10 20:06:27 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.23 2008/05/02 01:08:26 tgl Exp $ -->
<chapter id="storage">
</caution>
<para>
-When a table or index exceeds 1 GB, it is normally divided into gigabyte-sized
+When a table or index exceeds 1 GB, it is divided into gigabyte-sized
<firstterm>segments</>. The first segment's file name is the same as the
filenode; subsequent segments are named filenode.1, filenode.2, etc.
This arrangement avoids problems on platforms that have file size limitations.
-(But if the platform does not have such a limitation, and
-<option>--disable-segmented-files</option> was specified when
-<productname>PostgreSQL</> was built, then each table or index is stored
-as a single file, without segmentation.)
+(Actually, 1 GB is just the default segment size. The segment size can be
+adjusted using the configuration option <option>--with-segsize</option>
+when building <productname>PostgreSQL</>.)
The contents of tables and indexes are discussed further in
<xref linkend="storage-page-layout">.
</para>
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.30 2008/03/10 20:06:27 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.31 2008/05/02 01:08:27 tgl Exp $
*
* NOTES:
*
#include "storage/buffile.h"
/*
- * We break BufFiles into gigabyte-sized segments, whether or not
- * USE_SEGMENTED_FILES is defined. The reason is that we'd like large
- * temporary BufFiles to be spread across multiple tablespaces when available.
+ * We break BufFiles into gigabyte-sized segments, regardless of RELSEG_SIZE.
+ * The reason is that we'd like large temporary BufFiles to be spread across
+ * multiple tablespaces when available.
*/
#define MAX_PHYSICAL_FILESIZE 0x40000000
#define BUFFILE_SEG_SIZE (MAX_PHYSICAL_FILESIZE / BLCKSZ)
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.137 2008/04/18 06:48:38 heikki Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.138 2008/05/02 01:08:27 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* system's file size limit (often 2GBytes). In order to do that,
* we break relations up into "segment" files that are each shorter than
* the OS file size limit. The segment size is set by the RELSEG_SIZE
- * configuration constant in pg_config_manual.h.
+ * configuration constant in pg_config.h.
*
* On disk, a relation must consist of consecutively numbered segment
* files in the pattern
* segment, we assume that any subsequent segments are inactive.
*
* All MdfdVec objects are palloc'd in the MdCxt memory context.
- *
- * On platforms that support large files, USE_SEGMENTED_FILES can be
- * #undef'd to disable the segmentation logic. In that case each
- * relation is a single operating-system file.
*/
typedef struct _MdfdVec
{
File mdfd_vfd; /* fd number in fd.c's pool */
BlockNumber mdfd_segno; /* segment number, from 0 */
-#ifdef USE_SEGMENTED_FILES
struct _MdfdVec *mdfd_chain; /* next segment, or NULL */
-#endif
} MdfdVec;
static MemoryContext MdCxt; /* context for all md.c allocations */
static void register_dirty_segment(SMgrRelation reln, MdfdVec *seg);
static void register_unlink(RelFileNode rnode);
static MdfdVec *_fdvec_alloc(void);
-
-#ifdef USE_SEGMENTED_FILES
static MdfdVec *_mdfd_openseg(SMgrRelation reln, BlockNumber segno,
int oflags);
-#endif
static MdfdVec *_mdfd_getseg(SMgrRelation reln, BlockNumber blkno,
bool isTemp, ExtensionBehavior behavior);
static BlockNumber _mdnblocks(SMgrRelation reln, MdfdVec *seg);
reln->md_fd->mdfd_vfd = fd;
reln->md_fd->mdfd_segno = 0;
-#ifdef USE_SEGMENTED_FILES
reln->md_fd->mdfd_chain = NULL;
-#endif
}
/*
path = relpath(rnode);
/*
- * Delete or truncate the first segment, or only segment if not doing
- * segmenting
+ * Delete or truncate the first segment.
*/
if (isRedo)
ret = unlink(path);
rnode.relNode)));
}
-#ifdef USE_SEGMENTED_FILES
- /* Delete the additional segments, if any */
+ /*
+ * Delete any additional segments.
+ */
else
{
char *segpath = (char *) palloc(strlen(path) + 12);
}
pfree(segpath);
}
-#endif
pfree(path);
v = _mdfd_getseg(reln, blocknum, isTemp, EXTENSION_CREATE);
-#ifdef USE_SEGMENTED_FILES
seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (off_t) BLCKSZ * blocknum;
-#endif
/*
* Note: because caller usually obtained blocknum by calling mdnblocks,
if (!isTemp)
register_dirty_segment(reln, v);
-#ifdef USE_SEGMENTED_FILES
Assert(_mdnblocks(reln, v) <= ((BlockNumber) RELSEG_SIZE));
-#endif
}
/*
mdfd->mdfd_vfd = fd;
mdfd->mdfd_segno = 0;
-#ifdef USE_SEGMENTED_FILES
mdfd->mdfd_chain = NULL;
Assert(_mdnblocks(reln, mdfd) <= ((BlockNumber) RELSEG_SIZE));
-#endif
return mdfd;
}
reln->md_fd = NULL; /* prevent dangling pointer after error */
-#ifdef USE_SEGMENTED_FILES
while (v != NULL)
{
MdfdVec *ov = v;
v = v->mdfd_chain;
pfree(ov);
}
-#else
- if (v->mdfd_vfd >= 0)
- FileClose(v->mdfd_vfd);
- pfree(v);
-#endif
}
/*
v = _mdfd_getseg(reln, blocknum, false, EXTENSION_FAIL);
-#ifdef USE_SEGMENTED_FILES
seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (off_t) BLCKSZ * blocknum;
-#endif
if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
ereport(ERROR,
v = _mdfd_getseg(reln, blocknum, isTemp, EXTENSION_FAIL);
-#ifdef USE_SEGMENTED_FILES
seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
Assert(seekpos < (off_t) BLCKSZ * RELSEG_SIZE);
-#else
- seekpos = (off_t) BLCKSZ * blocknum;
-#endif
if (FileSeek(v->mdfd_vfd, seekpos, SEEK_SET) != seekpos)
ereport(ERROR,
mdnblocks(SMgrRelation reln)
{
MdfdVec *v = mdopen(reln, EXTENSION_FAIL);
-
-#ifdef USE_SEGMENTED_FILES
BlockNumber nblocks;
BlockNumber segno = 0;
v = v->mdfd_chain;
}
-#else
- return _mdnblocks(reln, v);
-#endif
}
/*
{
MdfdVec *v;
BlockNumber curnblk;
-
-#ifdef USE_SEGMENTED_FILES
BlockNumber priorblocks;
-#endif
/*
* NOTE: mdnblocks makes sure we have opened all active segments, so that
v = mdopen(reln, EXTENSION_FAIL);
-#ifdef USE_SEGMENTED_FILES
priorblocks = 0;
while (v != NULL)
{
}
priorblocks += RELSEG_SIZE;
}
-#else
- /* For unsegmented files, it's a lot easier */
- if (FileTruncate(v->mdfd_vfd, (off_t) nblocks * BLCKSZ) < 0)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not truncate relation %u/%u/%u to %u blocks: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode,
- nblocks)));
- if (!isTemp)
- register_dirty_segment(reln, v);
-#endif
}
/*
v = mdopen(reln, EXTENSION_FAIL);
-#ifdef USE_SEGMENTED_FILES
while (v != NULL)
{
if (FileSync(v->mdfd_vfd) < 0)
reln->smgr_rnode.relNode)));
v = v->mdfd_chain;
}
-#else
- if (FileSync(v->mdfd_vfd) < 0)
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not fsync relation %u/%u/%u: %m",
- reln->smgr_rnode.spcNode,
- reln->smgr_rnode.dbNode,
- reln->smgr_rnode.relNode)));
-#endif
}
/*
return (MdfdVec *) MemoryContextAlloc(MdCxt, sizeof(MdfdVec));
}
-#ifdef USE_SEGMENTED_FILES
-
/*
* Open the specified segment of the relation,
* and make a MdfdVec object for it. Returns NULL on failure.
/* all done */
return v;
}
-#endif /* USE_SEGMENTED_FILES */
/*
* _mdfd_getseg() -- Find the segment of the relation holding the
ExtensionBehavior behavior)
{
MdfdVec *v = mdopen(reln, behavior);
-
-#ifdef USE_SEGMENTED_FILES
BlockNumber targetseg;
BlockNumber nextsegno;
}
v = v->mdfd_chain;
}
-#endif
-
return v;
}
/* The normal alignment of `short', in bytes. */
#undef ALIGNOF_SHORT
+/* Size of a disk block --- this also limits the size of a tuple. You can set
+ it bigger if you need bigger tuples (although TOAST should reduce the need
+ to have large tuples, since fields can be spread across multiple tuples).
+ BLCKSZ must be a power of 2. The maximum possible value of BLCKSZ is
+ currently 2^15 (32768). This is determined by the 15-bit widths of the
+ lp_off and lp_len fields in ItemIdData (see include/storage/itemid.h).
+ Changing BLCKSZ requires an initdb. */
+#undef BLCKSZ
+
/* Define to the default TCP port number on which the server listens and to
which clients will try to connect. This can be overridden at run-time, but
it's convenient if your clients have the right default compiled in.
your system. */
#undef PTHREAD_CREATE_JOINABLE
+/* RELSEG_SIZE is the maximum number of blocks allowed in one disk file. Thus,
+ the maximum size of a single file is RELSEG_SIZE * BLCKSZ; relations bigger
+ than that are divided into multiple files. RELSEG_SIZE * BLCKSZ must be
+ less than your OS' limit on file size. This is often 2 GB or 4GB in a
+ 32-bit operating system, unless you have large file support enabled. By
+ default, we make the limit 1 GB to avoid any possible integer-overflow
+ problems within the OS. A limit smaller than necessary only means we divide
+ a large relation into more chunks than necessary, so it seems best to err
+ in the direction of a small limit. A power-of-2 value is recommended to
+ save a few cycles in md.c, but is not absolutely required. Changing
+ RELSEG_SIZE requires an initdb. */
+#undef RELSEG_SIZE
+
/* The size of `off_t', as computed by sizeof. */
#undef SIZEOF_OFF_T
/* Use replacement snprintf() functions. */
#undef USE_REPL_SNPRINTF
-/* Define to split data files into 1GB segments. */
-#undef USE_SEGMENTED_FILES
-
/* Define to build with (Open)SSL support. (--with-openssl) */
#undef USE_SSL
* for developers. If you edit any of these, be sure to do a *full*
* rebuild (and an initdb if noted).
*
- * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.31 2008/04/11 22:54:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.32 2008/05/02 01:08:27 tgl Exp $
*------------------------------------------------------------------------
*/
/*
- * Size of a disk block --- this also limits the size of a tuple. You
- * can set it bigger if you need bigger tuples (although TOAST should
- * reduce the need to have large tuples, since fields can be spread
- * across multiple tuples).
- *
- * BLCKSZ must be a power of 2. The maximum possible value of BLCKSZ
- * is currently 2^15 (32768). This is determined by the 15-bit widths
- * of the lp_off and lp_len fields in ItemIdData (see
- * include/storage/itemid.h).
- *
- * Changing BLCKSZ requires an initdb.
- */
-#define BLCKSZ 8192
-
-/*
- * RELSEG_SIZE is the maximum number of blocks allowed in one disk
- * file when USE_SEGMENTED_FILES is defined. Thus, the maximum size
- * of a single file is RELSEG_SIZE * BLCKSZ; relations bigger than that
- * are divided into multiple files.
- *
- * RELSEG_SIZE * BLCKSZ must be less than your OS' limit on file size.
- * This is often 2 GB or 4GB in a 32-bit operating system, unless you
- * have large file support enabled. By default, we make the limit 1
- * GB to avoid any possible integer-overflow problems within the OS.
- * A limit smaller than necessary only means we divide a large
- * relation into more chunks than necessary, so it seems best to err
- * in the direction of a small limit. (Besides, a power-of-2 value
- * saves a few cycles in md.c.)
- *
- * When not using segmented files, RELSEG_SIZE is set to zero so that
- * this behavior can be distinguished in pg_control.
- *
- * Changing RELSEG_SIZE requires an initdb.
- */
-#ifdef USE_SEGMENTED_FILES
-#define RELSEG_SIZE (0x40000000 / BLCKSZ)
-#else
-#define RELSEG_SIZE 0
-#endif
-
-/*
* Size of a WAL file block. This need have no particular relation to BLCKSZ.
* XLOG_BLCKSZ must be a power of 2, and if your system supports O_DIRECT I/O,
* XLOG_BLCKSZ must be a multiple of the alignment requirement for direct-I/O
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