Make the "split to deepen the tree" configuration values real, stored

in the metadata file, but they remain undocumented for now.

5 files changed, 50 insertions, 21 deletions

diff --git a/dist/api_data.py b/dist/api_data.py
index 7754a3a1d13..65af833c4a2 100644
--- a/dist/api_data.py
+++ b/dist/api_data.py
@@ -241,6 +241,12 @@ file_config = format_meta + [
         minimum gain before prefix compression will be used on row-store
         leaf pages''',
         min=0),
+    Config('split_deepen_min_child', '0', r'''
+        minimum entries in a page to consider deepening the tree''',
+        type='int', undoc=True),
+    Config('split_deepen_per_child', '0', r'''
+        entries allocated per child when deepening the tree''',
+        type='int', undoc=True),
     Config('split_pct', '75', r'''
         the Btree page split size as a percentage of the maximum Btree
         page size, that is, when a Btree page is split, it will be
diff --git a/src/btree/bt_handle.c b/src/btree/bt_handle.c
index f0414c4e855..14d16afb9a3 100644
--- a/src/btree/bt_handle.c
+++ b/src/btree/bt_handle.c
@@ -676,6 +676,22 @@ __btree_page_sizes(WT_SESSION_IMPL *session)
 	leaf_split_size = __wt_split_page_size(btree, btree->maxleafpage);
 
 	/*
+	 * In-memory split configuration.
+	 */
+	if (__wt_config_gets(
+	    session, cfg, "split_deepen_min_child", &cval) == WT_NOTFOUND ||
+	    cval.val == 0)
+		btree->split_deepen_min_child = WT_SPLIT_DEEPEN_MIN_CHILD_DEF;
+	else
+		btree->split_deepen_min_child = (u_int)cval.val;
+	if (__wt_config_gets(
+	    session, cfg, "split_deepen_per_child", &cval) == WT_NOTFOUND ||
+	    cval.val == 0)
+		btree->split_deepen_per_child = WT_SPLIT_DEEPEN_PER_CHILD_DEF;
+	else
+		btree->split_deepen_per_child = (u_int)cval.val;
+
+	/*
 	 * Get the maximum internal/leaf page key/value sizes.
 	 *
 	 * In historic versions of WiredTiger, the maximum internal/leaf page
diff --git a/src/btree/bt_split.c b/src/btree/bt_split.c
index e4fe51ea28f..aa7fc011cd8 100644
--- a/src/btree/bt_split.c
+++ b/src/btree/bt_split.c
@@ -169,13 +169,6 @@ __split_safe_free(WT_SESSION_IMPL *session, int exclusive, void *p, size_t s)
 }
 
 /*
- * Tuning; global variables to allow the binary to be patched, we don't yet have
- * any real understanding of what might be useful to surface to applications.
- */
-static u_int __split_deepen_min_child = 10000;
-static u_int __split_deepen_per_child = 100;
-
-/*
  * __split_should_deepen --
  *	Return if we should deepen the tree.
  */
@@ -183,11 +176,13 @@ static int
 __split_should_deepen(
     WT_SESSION_IMPL *session, WT_REF *ref, uint32_t *childrenp)
 {
-	WT_PAGE_INDEX *pindex;
+	WT_BTREE *btree;
 	WT_PAGE *page;
+	WT_PAGE_INDEX *pindex;
 
 	*childrenp = 0;
 
+	btree = S2BT(session);
 	page = ref->page;
 	pindex = WT_INTL_INDEX_COPY(page);
 
@@ -204,8 +199,8 @@ __split_should_deepen(
 	 * we get a significant payback (in the case of a set of large keys,
 	 * splitting won't help).
 	 */
-	if (pindex->entries > __split_deepen_min_child) {
-		*childrenp = pindex->entries / __split_deepen_per_child;
+	if (pindex->entries > btree->split_deepen_min_child) {
+		*childrenp = pindex->entries / btree->split_deepen_per_child;
 		return (1);
 	}
 
diff --git a/src/config/config_def.c b/src/config/config_def.c
index 646551cdd38..a7e9419a65c 100644
--- a/src/config/config_def.c
+++ b/src/config/config_def.c
@@ -152,6 +152,8 @@ static const WT_CONFIG_CHECK confchk_file_meta[] = {
 	{ "os_cache_max", "int", "min=0", NULL },
 	{ "prefix_compression", "boolean", NULL, NULL },
 	{ "prefix_compression_min", "int", "min=0", NULL },
+	{ "split_deepen_min_child", "int", NULL, NULL },
+	{ "split_deepen_per_child", "int", NULL, NULL },
 	{ "split_pct", "int", "min=25,max=100", NULL },
 	{ "value_format", "format", NULL, NULL },
 	{ "version", "string", NULL, NULL },
@@ -246,6 +248,8 @@ static const WT_CONFIG_CHECK confchk_session_create[] = {
 	{ "prefix_compression", "boolean", NULL, NULL },
 	{ "prefix_compression_min", "int", "min=0", NULL },
 	{ "source", "string", NULL, NULL },
+	{ "split_deepen_min_child", "int", NULL, NULL },
+	{ "split_deepen_per_child", "int", NULL, NULL },
 	{ "split_pct", "int", "min=25,max=100", NULL },
 	{ "type", "string", NULL, NULL },
 	{ "value_format", "format", NULL, NULL },
@@ -585,7 +589,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  ",key_format=u,key_gap=10,leaf_item_max=0,leaf_key_max=0,"
 	  "leaf_page_max=32KB,leaf_value_max=0,memory_page_max=5MB,"
 	  "os_cache_dirty_max=0,os_cache_max=0,prefix_compression=0,"
-	  "prefix_compression_min=4,split_pct=75,value_format=u,"
+	  "prefix_compression_min=4,split_deepen_min_child=0,"
+	  "split_deepen_per_child=0,split_pct=75,value_format=u,"
 	  "version=(major=0,minor=0)",
 	  confchk_file_meta
 	},
@@ -626,8 +631,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  "bloom_hash_count=8,bloom_oldest=0,chunk_max=5GB,chunk_size=10MB,"
 	  "merge_max=15,merge_min=0),memory_page_max=5MB,"
 	  "os_cache_dirty_max=0,os_cache_max=0,prefix_compression=0,"
-	  "prefix_compression_min=4,source=,split_pct=75,type=file,"
-	  "value_format=u",
+	  "prefix_compression_min=4,source=,split_deepen_min_child=0,"
+	  "split_deepen_per_child=0,split_pct=75,type=file,value_format=u",
 	  confchk_session_create
 	},
 	{ "session.drop",
diff --git a/src/include/btree.h b/src/include/btree.h
index fa01dd5edc2..dd3acf6940d 100644
--- a/src/include/btree.h
+++ b/src/include/btree.h
@@ -98,14 +98,21 @@ struct __wt_btree {
 		CKSUM_UNCOMPRESSED=3	/* Uncompressed blocks only */
 	} checksum;			/* Checksum configuration */
 
-	u_int dictionary;		/* Reconcile: dictionary slots */
-	int   internal_key_truncate;	/* Reconcile: internal key truncate */
-	int   maximum_depth;		/* Reconcile: maximum tree depth */
-	int   prefix_compression;	/* Reconcile: prefix compression */
-	u_int prefix_compression_min;	/* Reconcile: prefix compression min */
-	int   split_pct;		/* Reconcile: split page percent */
-	WT_COMPRESSOR *compressor;	/* Reconcile: page compressor */
-	WT_RWLOCK *ovfl_lock;		/* Reconcile: overflow lock */
+	/*
+	 * Reconciliation...
+	 */
+	u_int dictionary;		/* Dictionary slots */
+	int   internal_key_truncate;	/* Internal key truncate */
+	int   maximum_depth;		/* Maximum tree depth */
+	int   prefix_compression;	/* Prefix compression */
+	u_int prefix_compression_min;	/* Prefix compression min */
+#define	WT_SPLIT_DEEPEN_MIN_CHILD_DEF	10000
+	u_int split_deepen_min_child;	/* Minimum entries to deepen tree */
+#define	WT_SPLIT_DEEPEN_PER_CHILD_DEF	100
+	u_int split_deepen_per_child;	/* Entries per child when deepened */
+	int   split_pct;		/* Split page percent */
+	WT_COMPRESSOR *compressor;	/* Page compressor */
+	WT_RWLOCK *ovfl_lock;		/* Overflow lock */
 
 	uint64_t last_recno;		/* Column-store last record number */