Replace internal_node_min/leaf_node_min (the minimum page size)

configuration with internal_overflow_size/leaf_overflow_size (explicit
configuration of the size of an overflow item.

Fix a bug where we never actually paid any attention to the internal
overflow item size, even though we set it.

Delete the split_min debugging configuration string: the problem is that
small pages now have to be set in concert with the overflow size, if
there is an overflow size that's relatively large, and we create a split
page smaller than an item which is itself smaller than the overflow
size, the item will never fit on the page and we loop forever.  I
haven't chased any bugs in reconciliation's page size in quite awhile,
hopefully split_min is no longer interesting.

Write a basic performance tuning page for the documentation.

--HG--
extra : rebase_source : 0825ab4ff58b2dcb18675290f299fad0f5eaaae7

5 files changed, 24 insertions, 35 deletions

diff --git a/test/format/config.c b/test/format/config.c
index 3d09a1e20a1..dc6d386e914 100644
--- a/test/format/config.c
+++ b/test/format/config.c
@@ -62,15 +62,6 @@ config_setup(void)
 	/* Periodically, set the delete percentage to 0 so salvage gets run. */
 	if (!g.replay && g.run_cnt % 10 == 0)
 		g.c_delete_pct = 0;
-
-	/*
-	 * There are a couple of corrections the table doesn't handle, where
-	 * initialized values are relative to each other.
-	 */
-	if (g.c_intl_node_max < g.c_intl_node_min)
-		g.c_intl_node_max = g.c_intl_node_min;
-	if (g.c_leaf_node_max < g.c_leaf_node_min)
-		g.c_leaf_node_max = g.c_leaf_node_min;
 }
 
 /*
diff --git a/test/format/config.h b/test/format/config.h
index 20a08d593c4..e4a9f5b8cc0 100644
--- a/test/format/config.h
+++ b/test/format/config.h
@@ -72,10 +72,6 @@ static CONFIG c[] = {
 	  "maximum size of Btree internal nodes",
 	  0, 0, 9, 17, &g.c_intl_node_max },
 
-	{ "intl_node_min",
-	  "minimum size of Btree internal nodes",
-	  0, 0, 9, 17, &g.c_intl_node_min },
-
 	{ "key_max",
 	  "maximum size of keys",
 	  C_ROW, 0, 64, 128, &g.c_key_max },
@@ -88,10 +84,6 @@ static CONFIG c[] = {
 	  "maximum size of Btree leaf nodes",
 	  0, 0, 9, 17, &g.c_leaf_node_max },
 
-	{ "leaf_node_min",
-	  "minimum size of Btree leaf nodes",
-	  0, 0, 9, 17, &g.c_leaf_node_min },
-
 	{ "multithread",
 	  "configured for multi-threading",		/* 50% */
 	  0, C_BOOL, 50, 0, &g.c_multithread },
diff --git a/test/format/format.h b/test/format/format.h
index 471b7083c0a..e741c058af5 100644
--- a/test/format/format.h
+++ b/test/format/format.h
@@ -33,7 +33,7 @@
 #define	VAR		3
 
 /* Get a random value between a min/max pair. */
-#define	MMRAND(min, max)	(wts_rand() % ((max + 1) - (min)) + (min))
+#define	MMRAND(min, max)	(wts_rand() % (((max) + 1) - (min)) + (min))
 
 #define	WT_TABLENAME	"file:__wt"
 
@@ -71,11 +71,9 @@ typedef struct {
 	uint32_t c_huffman_value;
 	uint32_t c_insert_pct;
 	uint32_t c_intl_node_max;
-	uint32_t c_intl_node_min;
 	uint32_t c_key_max;
 	uint32_t c_key_min;
 	uint32_t c_leaf_node_max;
-	uint32_t c_leaf_node_min;
 	uint32_t c_multithread;
 	uint32_t c_ops;
 	uint32_t c_repeat_data_pct;
diff --git a/test/format/wts.c b/test/format/wts.c
index bee2219199d..8330ec7de50 100644
--- a/test/format/wts.c
+++ b/test/format/wts.c
@@ -119,23 +119,30 @@ wts_startup(int open_cursors)
 	WT_CONNECTION *conn;
 	WT_CURSOR *cursor, *cursor_insert;
 	WT_SESSION *session;
+	uint32_t intlmax, intlovfl, leafmax, leafovfl;
 	int ret;
 	char config[512], *end, *p;
 
 	if (wts_open(&conn, &session))
 		return (1);
 
+	intlmax = 1U << g.c_intl_node_max;
+	intlovfl = MMRAND(intlmax / 50, intlmax / 40);
+	if (intlovfl < 40)
+		intlovfl = 40;
+	leafmax = 1U << g.c_leaf_node_max;
+	leafovfl = MMRAND(leafmax / 50, leafmax / 40);
+	if (leafovfl < 40)
+		leafovfl = 40;
+
 	p = config;
 	end = config + sizeof(config);
 	p += snprintf(p, (size_t)(end - p),
 	    "key_format=%s,"
-	    "internal_node_min=%d,internal_node_max=%d,"
-	    "leaf_node_min=%d,leaf_node_max=%d,split_min",
+	    "internal_node_max=%d,internal_overflow_size=%d,"
+	    "leaf_node_max=%d,leaf_overflow_size=%d",
 	    (g.c_file_type == ROW) ? "u" : "r",
-	    1U << g.c_intl_node_min,
-	    1U << g.c_intl_node_max,
-	    1U << g.c_leaf_node_min,
-	    1U << g.c_leaf_node_max);
+	    intlmax, intlovfl, leafmax, leafovfl);
 
 	if (g.c_bzip)
 		p += snprintf(p, (size_t)(end - p),
diff --git a/test/salvage/salvage.c b/test/salvage/salvage.c
index 5f602f2b392..6fc05f8345d 100644
--- a/test/salvage/salvage.c
+++ b/test/salvage/salvage.c
@@ -25,6 +25,7 @@
 #define	SLVG	"__slvg.build"			/* Salvage file */
 
 #define	PSIZE	(2 * 1024)
+#define	OSIZE	(PSIZE / 20)
 
 void build(int, int, int);
 void copy(u_int, u_int);
@@ -448,25 +449,25 @@ build(int ikey, int ivalue, int cnt)
 		(void)snprintf(config, sizeof(config),
 		    "key_format=r,value_format=7t,"
 		    "allocation_size=%d,"
-		    "internal_node_min=%d,internal_node_max=%d,"
-		    "leaf_node_min=%d,leaf_node_max=%d",
-		    PSIZE, PSIZE, PSIZE, PSIZE, PSIZE);
+		    "internal_node_max=%d,internal_overflow_size=%d,"
+		    "leaf_node_max=%d,leaf_overflow_size=%d",
+		    PSIZE, PSIZE, OSIZE, PSIZE, OSIZE);
 		break;
 	case WT_PAGE_COL_VAR:
 		(void)snprintf(config, sizeof(config),
 		    "key_format=r,"
 		    "allocation_size=%d,"
-		    "internal_node_min=%d,internal_node_max=%d,"
-		    "leaf_node_min=%d,leaf_node_max=%d",
-		    PSIZE, PSIZE, PSIZE, PSIZE, PSIZE);
+		    "internal_node_max=%d,internal_overflow_size=%d,"
+		    "leaf_node_max=%d,leaf_overflow_size=%d",
+		    PSIZE, PSIZE, OSIZE, PSIZE, OSIZE);
 		break;
 	case WT_PAGE_ROW_LEAF:
 		(void)snprintf(config, sizeof(config),
 		    "key_format=u,"
 		    "allocation_size=%d,"
-		    "internal_node_min=%d,internal_node_max=%d,"
-		    "leaf_node_min=%d,leaf_node_max=%d",
-		    PSIZE, PSIZE, PSIZE, PSIZE, PSIZE);
+		    "internal_node_max=%d,internal_overflow_size=%d,"
+		    "leaf_node_max=%d,leaf_overflow_size=%d",
+		    PSIZE, PSIZE, OSIZE, PSIZE, OSIZE);
 		break;
 	default:
 		assert(0);