# Running the first probe as a single process is required to avoid "File exists"
# errors. It seems that fresh database creation does not support concurrency.
Index: test.sh
--- test.sh	2007-07-29 21:07:10 +0200
+++ test.sh	2007-07-29 22:56:24 +0200
@@ -9,11 +9,11 @@
 
 echo "---- probing linear run"
 rm /tmp/my.db; rm -rf /tmp/my.d; mkdir /tmp/my.d || exit 1
-for i in 0 1 2 3 4 5 6 7 8 9; do ./probe ; done
+./probe; for i in 1 2 3 4 5 6 7 8 9; do ./probe ; done
 /openpkg-dev/bin/db_dump -p /tmp/my.db | egrep '^ key-' | wc -l
 
 echo "---- probing concurrent run"
 rm /tmp/my.db; rm -rf /tmp/my.d; mkdir /tmp/my.d || exit 1
-for i in 0 1 2 3 4 5 6 7 8 9; do ./probe & done; wait
+./probe; for i in 1 2 3 4 5 6 7 8 9; do ./probe & done; wait
 /openpkg-dev/bin/db_dump -p /tmp/my.db | egrep '^ key-' | wc -l

# Cosmetics
Index: test.sh
--- test.sh	2007-07-29 21:07:10 +0200
+++ test.sh	2007-07-29 22:56:24 +0200
@@ -5,7 +5,7 @@
 
 echo "---- building probe"
 uname | grep SunOS && EXTRALIBS='-l rt'
-/openpkg-dev/bin/gcc -I /openpkg-dev/include/ -L /openpkg-dev/lib/ -o probe probe.c -l db $EXTRALIBS || exit 1
+/openpkg-dev/bin/gcc -Wall -I /openpkg-dev/include/ -L /openpkg-dev/lib/ -o probe probe.c -l db $EXTRALIBS || exit 1
 
 echo "---- probing linear run"
 rm /tmp/my.db; rm -rf /tmp/my.d; mkdir /tmp/my.d || exit 1
Index: probe.c
--- probe.c	2007-07-29 20:56:27 +0200
+++ probe.c	2007-07-29 23:22:48 +0200
@@ -24,12 +24,10 @@
     sprintf(key, "key-%05d-%05d-%05d", (int)getpid(), o, i); dbkey.data = &key; dbkey.size = strlen(key);
     sprintf(val, "val-%05d-%05d-%05d", (int)getpid(), o, i); dbval.data = &val; dbval.size = strlen(val);
 
-#if 0
-    printf("key=%s, val=%s\n", key, val);
-#else
     rv = db->put(db, NULL, &dbkey, &dbval, DB_NOOVERWRITE);
-    if (rv != 0) die(rv);
-#endif
+    if (rv != 0) {
+        fprintf(stderr, "WARNING: key=%s, val=%s error(%d)=%s\n", key, val, rv, db_strerror(rv));
+    }
 }
 
 int main(void)
@@ -55,7 +55,8 @@
         flags |= DB_RECOVER;
         if ((rv = dbenv->open(dbenv,   /* DB environment pointer */
                           "/tmp/my.d", /* Homedir */
-                          flags, 0)    /* Open flags, File mode (using defaults) */
+                          flags,       /* Open flags */
+                          0)           /* File mode (using defaults) */
             ) != 0) die(rv);
 
         /* Initialize and open the database */
@@ -71,7 +69,8 @@
                        "/tmp/my.db", /* On-disk file that holds the database.  */
                        "foo",        /* Optional logical database name */
                        DB_BTREE,     /* Database access method */
-                       flags, 0)     /* Open flags, File mode (using defaults) */
+                       flags,        /* Open flags */
+                       0)            /* File mode (using defaults) */
             ) != 0) die(rv);
 
         /* Put content into database */

# reduce use of die() macro to the main function only and enhance to call proper cleanup sequence.
Index: probe.c
--- probe.c	2007-07-29 20:56:27 +0200
+++ probe.c	2007-07-29 23:22:48 +0200
@@ -7,9 +7,9 @@
 #include <string.h>
 #include <db.h>
 
-#define die(e) { fprintf(stderr, "ERROR file %s line %d pid=%d: %s (%d)\n", \
+#define die(e) { fprintf(stderr, "DIE: file %s line %d pid=%d: %s (%d)\n", \
                  __FILE__, __LINE__, (int)getpid(), db_strerror(e), e); \
-                 exit(e); }
+                 goto CLEANUP; }
 
 void insert(DB *db, int o, int i)
 {
@@ -77,6 +77,7 @@
         /* Put content into database */
         for (i=0; i<100; i++) insert(db, o, i);
        
+CLEANUP:
         /* Flush, cleanup and close database and environment */
         if (db != NULL) db->close(db, 0); 
         if (dbenv != NULL) dbenv->close(dbenv, 0); 

# DB_INIT_LOCK is the wholly grail to enabling concurrency.
# DB_INIT_MPOOL used to prevent error "environment did not include a memory pool".
# DB_INIT_TXN used to prevent error "recovery requires transaction support".
# DB_RECOVER used to prevent error "No recovery flag was specified, and recovery is needed"
Index: probe.c
--- probe.c	2007-07-29 20:56:27 +0200
+++ probe.c	2007-07-29 23:22:48 +0200
@@ -48,6 +48,8 @@
         dbenv->set_errfile(dbenv, stderr);
         flags = 0;
         flags |= DB_CREATE;
+        flags |= DB_INIT_MPOOL;
+        flags |= DB_INIT_LOCK;
         flags |= DB_INIT_TXN;
         flags |= DB_REGISTER;
         flags |= DB_RECOVER;

# the environment only helps if passed to db_create
Index: probe.c
--- probe.c	2007-07-29 20:56:27 +0200
+++ probe.c	2007-07-29 23:22:48 +0200
@@ -61,7 +61,7 @@
 
         /* Initialize and open the database */
         db = NULL;
-        rv = db_create(&db, NULL, 0);
+        rv = db_create(&db, dbenv, 0);
         if (rv != 0) die(rv);
 
         db->set_errfile(db, stderr);