database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Remove the recently added USE_SEGMENTED_FILES option, and indeed remove all

Browse Source 
support for a nonsegmented mode from md.c.  Per recent discussions, there
doesn't seem to be much value in a "never segment" option as opposed to
segmenting with a suitably large segment size.  So instead provide a
configure-time switch to set the desired segment size in units of gigabytes.
While at it, expose a configure switch for BLCKSZ as well.

Zdenek Kotala
This commit is contained in:
Tom Lane
2008-05-02 01:08:27 +00:00
parent 94b0b545f8
commit 3c6248a828
8 changed files with 223 additions and 170 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
configure.in
View File

@ -1,5 +1,5 @@
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
@ -155,7 +155,7 @@ AC_SUBST(WANTED_LANGUAGES)
# 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])
@ -218,10 +218,67 @@ AC_SUBST(DTRACEFLAGS)])
AC_SUBST(enable_dtrace)
#
# Data file segmentation
# Block size
#
PGAC_ARG_BOOL(enable, segmented-files, yes,
[ --disable-segmented-files disable data file segmentation (requires largefile support)])
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], ${RELSEG_SIZE}, [
RELSEG_SIZE is the maximum number of blocks allowed in one disk file.
Thus, the maximum size of a single file is RELSEG_SIZE * BLCKSZ;
relations bigger than that are divided into multiple files.
RELSEG_SIZE * BLCKSZ must be less than your OS' limit on file size.
This is often 2 GB or 4GB in a 32-bit operating system, unless you
have large file support enabled. By default, we make the limit 1 GB
to avoid any possible integer-overflow problems within the OS.
A limit smaller than necessary only means we divide a large
relation into more chunks than necessary, so it seems best to err
in the direction of a small limit.
A power-of-2 value is recommended to save a few cycles in md.c,
but is not absolutely required.
Changing RELSEG_SIZE requires an initdb.
])
#
# C compiler
@ -1469,8 +1526,9 @@ fi
# Check for largefile support (must be after AC_SYS_LARGEFILE)
AC_CHECK_SIZEOF([off_t])
if test "$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