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anarazelanarazel
committedSep 20, 2017
Make WAL segment size configurable at initdb time.
For performance reasons a larger segment size than the default 16MB can be useful. A larger segment size has two main benefits: Firstly, in setups using archiving, it makes it easier to write scripts that can keep up with higher amounts of WAL, secondly, the WAL has to be written and synced to disk less frequently. But at the same time large segment size are disadvantageous for smaller databases. So far the segment size had to be configured at compile time, often making it unrealistic to choose one fitting to a particularly load. Therefore change it to a initdb time setting. This includes a breaking changes to the xlogreader.h API, which now requires the current segment size to be configured. For that and similar reasons a number of binaries had to be taught how to recognize the current segment size. Author: Beena Emerson, editorialized by Andres Freund Reviewed-By: Andres Freund, David Steele, Kuntal Ghosh, Michael Paquier, Peter Eisentraut, Robert Hass, Tushar Ahuja Discussion: https://postgr.es/m/CAOG9ApEAcQ--1ieKbhFzXSQPw_YLmepaa4hNdnY5+ZULpt81Mw@mail.gmail.com
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‎configure

Lines changed: 0 additions & 54 deletions
Original file line numberDiff line numberDiff line change
@@ -821,7 +821,6 @@ enable_tap_tests
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with_blocksize
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with_segsize
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with_wal_blocksize
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with_wal_segsize
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with_CC
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enable_depend
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enable_cassert
@@ -1518,8 +1517,6 @@ Optional Packages:
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--with-segsize=SEGSIZE set table segment size in GB [1]
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--with-wal-blocksize=BLOCKSIZE
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set WAL block size in kB [8]
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--with-wal-segsize=SEGSIZE
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set WAL segment size in MB [16]
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--with-CC=CMD set compiler (deprecated)
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--with-icu build with ICU support
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--with-tcl build Tcl modules (PL/Tcl)
@@ -3733,57 +3730,6 @@ cat >>confdefs.h <<_ACEOF
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_ACEOF
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#
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# WAL segment size
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#
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for WAL segment size" >&5
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$as_echo_n "checking for WAL segment size... " >&6; }
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# Check whether --with-wal-segsize was given.
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if test "${with_wal_segsize+set}" = set; then :
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withval=$with_wal_segsize;
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case $withval in
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yes)
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as_fn_error $? "argument required for --with-wal-segsize option" "$LINENO" 5
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;;
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no)
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as_fn_error $? "argument required for --with-wal-segsize option" "$LINENO" 5
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;;
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*)
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wal_segsize=$withval
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;;
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esac
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else
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wal_segsize=16
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fi
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case ${wal_segsize} in
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1) ;;
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2) ;;
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4) ;;
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8) ;;
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16) ;;
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32) ;;
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64) ;;
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128) ;;
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256) ;;
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512) ;;
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1024) ;;
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*) as_fn_error $? "Invalid WAL segment size. Allowed values are 1,2,4,8,16,32,64,128,256,512,1024." "$LINENO" 5
3777-
esac
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: ${wal_segsize}MB" >&5
3779-
$as_echo "${wal_segsize}MB" >&6; }
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cat >>confdefs.h <<_ACEOF
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#define XLOG_SEG_SIZE (${wal_segsize} * 1024 * 1024)
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_ACEOF
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#
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# C compiler
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#

‎configure.in

Lines changed: 0 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -343,37 +343,6 @@ AC_DEFINE_UNQUOTED([XLOG_BLCKSZ], ${XLOG_BLCKSZ}, [
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Changing XLOG_BLCKSZ requires an initdb.
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])
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#
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# WAL segment size
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#
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AC_MSG_CHECKING([for WAL segment size])
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PGAC_ARG_REQ(with, wal-segsize, [SEGSIZE], [set WAL segment size in MB [16]],
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[wal_segsize=$withval],
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[wal_segsize=16])
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case ${wal_segsize} in
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1) ;;
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2) ;;
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4) ;;
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8) ;;
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16) ;;
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32) ;;
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64) ;;
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128) ;;
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256) ;;
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512) ;;
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1024) ;;
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*) AC_MSG_ERROR([Invalid WAL segment size. Allowed values are 1,2,4,8,16,32,64,128,256,512,1024.])
366-
esac
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AC_MSG_RESULT([${wal_segsize}MB])
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AC_DEFINE_UNQUOTED([XLOG_SEG_SIZE], [(${wal_segsize} * 1024 * 1024)], [
370-
XLOG_SEG_SIZE is the size of a single WAL file. This must be a power of 2
371-
and larger than XLOG_BLCKSZ (preferably, a great deal larger than
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XLOG_BLCKSZ).
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Changing XLOG_SEG_SIZE requires an initdb.
375-
])
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#
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# C compiler
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#

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