From: Cees de Groot <C.deGroot@inter.nl.net>
Date: Wed, 19 Jun 1996 14:47:17 +0200
Subject: [PG95]: [OpenLink] Postgres'95 patches

Hi all,

Here are two minor patches which may or may not have been fixed yet (I'm
very sorry, but this mailing list didn't receive the attention it deserves
my me the last couple of months). Please don't start discussing about the
fsync () hack. We know quite well what it does, but it makes for very
nice demonstrations ;-).

The following files are also available in our private source distribution
of Postgres'95:

- -------------- patches/README
In order to keep track of our local changes, we have imported the Postgres
source tree into CVS.  As a consequence, some files have an incorrect
(unofficial) RCS identifier -- Sorry


This directory contains the following patches to the Postgres 95 Release 1.01
source tree.

To enable the patches, run patch with the diff file and add a define
- -DOPENLINK_PATCHES to the master makefile.


varchar.diff
- ------------
This patch was necessary for the OpenLink Postgres Database Agent.
I think this fixes a bug anyway.

The following query demonstrates this bug:

  create table foo (bar varchar);
  insert into foo values ('');		-- no problem
  select * from foo where bar = '';	-- fails


fsync.diff
- ----------
This patch adds an option to disable synchronous writes.
It adds an extra option to postgres: -F

When started with -F, all fsync() calls will be no-ops,
so you'll be in big trouble when your machine suddenly crashes and your disk
cache is not flushed.

Use at your own risk (but it is *much* faster with large inserts)

This also speeds up initdb for initial database bootstrapping

To start postmaster with this "feature" enabled, type
  postmaster -o -F -S

- -------patches/varchar.diff
Index: src/backend/utils/adt/varchar.c
===================================================================
RCS file: /usr/home/cvs/postgres95/src/backend/utils/adt/varchar.c,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 varchar.c
70a71
> #ifndef OPENLINK_PATCHES
72a74,77
> #else
>     if (len > 4096)
> 	elog(WARN, "bpcharin: length of char() must be less than 4096");
> #endif
134a140
> #ifndef OPENLINK_PATCHES
136a143,146
> #else
>     if (len > 4096)
> 	elog(WARN, "varcharin: length of char() must be less than 4096");
> #endif
- --------patches/fsync.diff
Index: src/backend/bootstrap/bootstrap.c
===================================================================
RCS file: /usr/home/cvs/postgres95/src/backend/bootstrap/bootstrap.c,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 bootstrap.c
138a139,141
> #ifdef OPENLINK_PATCHES
> extern int	fsyncOff;		/* do not fsync the database */
> #endif
200a204,206
> #ifdef OPENLINK_PATCHES
>     fprintf(stderr,"Usage: postgres -boot [-d] [-C] [-F] [-O] [-Q] [-P portno] [dbName]\n");
> #else
201a208
> #endif
203a211,213
> #ifdef OPENLINK_PATCHES
>     fprintf(stderr,"     F: turn off fsync\n");
> #endif
259c269,272
<     
- ---
> 
> #ifdef OPENLINK_PATCHES
>     while ((flag = getopt(argc, argv, "dCOQP:F")) != EOF) {
> #else
260a274
> #endif
275a290,295
> 	    break; 
> #ifdef OPENLINK_PATCHES
> 	case 'F':
> 	    fsyncOff = 1;
> 	    break;
> #endif
Index: src/backend/storage/file/fd.c
===================================================================
RCS file: /usr/home/cvs/postgres95/src/backend/storage/file/fd.c,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 fd.c
193a194,202
> #ifdef OPENLINK_PATCHES
> pg_fsync(fd)
> {
>     extern int fsyncOff;
>     return fsyncOff ? 0 : fsync(fd);
> }
> #define fsync pg_fsync
> #endif
> 
Index: src/backend/storage/smgr/md.c
===================================================================
RCS file: /usr/home/cvs/postgres95/src/backend/storage/smgr/md.c,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 md.c
474a475,477
> #ifdef OPENLINK_PATCHES
>     if (write(fd, buffer, BLCKSZ) != BLCKSZ || (pg_fsync(fd) < 0))
> #else
476a480
> #endif
Index: src/backend/tcop/postgres.c
===================================================================
RCS file: /usr/home/cvs/postgres95/src/backend/tcop/postgres.c,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 postgres.c
95a96,99
> #ifdef OPENLINK_PATCHES
> int	fsyncOff = 0;
> #endif
> 
701a706,708
> #ifdef OPENLINK_PATCHES
>     fprintf(stderr,"\t[-P portno] [-t tracetype] [-x opttype] [-bCEiLFNopQSs] [dbname]\n");
> #else
702a710
> #endif
710a719,721
> #ifdef OPENLINK_PATCHES
>     fprintf(stderr, "    F: turn off fsync\n");
> #endif
806a818,820
> #ifdef OPENLINK_PATCHES
>     while ((flag = getopt(argc, argv, "B:bCd:Ef:iLm:MNo:P:pQSst:x:F")) != EOF)
> #else
807a822
> #endif
891c906,916
< 	    
- ---
> 
> #ifdef OPENLINK_PATCHES
> 	case 'F':
> 	    /* --------------------
> 	     *  turn off fsync
> 	     * --------------------
> 	     */
> 	    fsyncOff = 1;
> 	    break;
> #endif
> 
Index: src/bin/initdb/initdb.sh
===================================================================
RCS file: /home/cvs/postgres95/src/bin/initdb/initdb.sh,v
retrieving revision 1.1.1.1
diff -r1.1.1.1 initdb.sh
62c62
<     BACKENDARGS="-boot -C -d"
- ---
>     BACKENDARGS="-boot -C -F -d"
64c64
<     BACKENDARGS="-boot -C -Q"
- ---
>     BACKENDARGS="-boot -C -F -Q"
219c219
<     echo "vacuum" | postgres -Q template1 > /dev/null
- ---
>     echo "vacuum" | postgres -F -Q template1 > /dev/null
222a223,224
> 
> sync
- ----------

Regards

Cees de Groot
OpenLink Software