Remove support for prefix-compression on row-store internal pages.

Ref #592.

1 files changed, 55 insertions, 19 deletions

diff --git a/src/include/cell.i b/src/include/cell.i
index a16db71819d..15a13064930 100644
--- a/src/include/cell.i
+++ b/src/include/cell.i
@@ -30,8 +30,8 @@
  *	Keys with optional data cells (a WT_CELL_KEY or WT_CELL_KEY_OVFL cell,
  *	optionally followed by a WT_CELL_{VALUE,VALUE_COPY,VALUE_OVFL} cell).
  *
- * Both WT_PAGE_ROW_INT and WT_PAGE_ROW_LEAF pages prefix compress keys, using
- * a single byte immediately following the cell.
+ *	WT_PAGE_ROW_LEAF pages prefix compress keys, using a single byte count
+ * immediately following the cell.
  *
  * WT_PAGE_COL_INT (Column-store internal page):
  *	Off-page references (a WT_CELL_{ADDR,ADDR_LNO} cell).
@@ -298,11 +298,41 @@ __wt_cell_pack_del(WT_CELL *cell, uint64_t rle)
 }
 
 /*
- * __wt_cell_pack_key --
- *	Set a key's WT_CELL contents.
+ * __wt_cell_pack_int_key --
+ *	Set a row-store internal page key's WT_CELL contents.
  */
 static inline uint32_t
-__wt_cell_pack_key(WT_CELL *cell, uint8_t prefix, uint32_t size)
+__wt_cell_pack_int_key(WT_CELL *cell, uint32_t size)
+{
+	uint8_t byte, *p;
+
+	/*
+	 * Short keys have 6-bits of length in the descriptor byte and no length
+	 * bytes.
+	 *
+	 * Bit 0 is 0, bit 1 is the WT_CELL_KEY_SHORT flag; the other 6 bits are
+	 * the size.
+	 */
+	if (size <= 0x3f) {
+		byte = (uint8_t)size;
+		cell->__chunk[0] = (byte << 2) | WT_CELL_KEY_SHORT;
+		return (1);
+	}
+
+	cell->__chunk[0] = WT_CELL_KEY;		/* Type */
+
+	p = cell->__chunk + 1;			/* Length */
+	(void)__wt_vpack_uint(&p, 0, (uint64_t)size);
+
+	return (WT_PTRDIFF32(p, cell));
+}
+
+/*
+ * __wt_cell_pack_leaf_key --
+ *	Set a row-store leaf page key's WT_CELL contents.
+ */
+static inline uint32_t
+__wt_cell_pack_leaf_key(WT_CELL *cell, uint8_t prefix, uint32_t size)
 {
 	uint8_t byte, *p;
 
@@ -446,7 +476,8 @@ __wt_cell_type_raw(WT_CELL *cell)
  *	Unpack a WT_CELL into a structure during verification.
  */
 static inline int
-__wt_cell_unpack_safe(WT_CELL *cell, WT_CELL_UNPACK *unpack, uint8_t *end)
+__wt_cell_unpack_safe(
+    WT_CELL *cell, int type, WT_CELL_UNPACK *unpack, uint8_t *end)
 {
 	uint64_t v;
 	const uint8_t *p;
@@ -506,14 +537,21 @@ restart:
 	switch (unpack->raw) {
 	case WT_CELL_KEY_SHORT:
 		/*
-		 * Check the prefix byte that follows the cell descriptor byte.
+		 * Check the prefix byte that follows the cell descriptor byte
+		 * on row-store leaf pages.
 		 */
-		WT_CELL_LEN_CHK(cell, 1);
-		unpack->prefix = cell->__chunk[1];
-
-		unpack->data = cell->__chunk + 2;
-		unpack->size = cell->__chunk[0] >> 2;
-		unpack->__len = 2 + unpack->size;
+		if (type == WT_PAGE_ROW_LEAF) {
+			WT_CELL_LEN_CHK(cell, 1);
+			unpack->prefix = cell->__chunk[1];
+
+			unpack->data = cell->__chunk + 2;
+			unpack->size = cell->__chunk[0] >> 2;
+			unpack->__len = 2 + unpack->size;
+		} else {
+			unpack->data = cell->__chunk + 1;
+			unpack->size = cell->__chunk[0] >> 2;
+			unpack->__len = 1 + unpack->size;
+		}
 		goto done;
 	case WT_CELL_VALUE_SHORT:
 		/*
@@ -532,10 +570,8 @@ restart:
 	 */
 	p = (uint8_t *)cell + 1;			/* skip cell */
 
-	if (unpack->raw == WT_CELL_KEY) {
-		/*
-		 * Check the prefix byte that follows the cell descriptor byte.
-		 */
+	/* Check the prefix byte that follows the cell descriptor byte. */
+	if (unpack->raw == WT_CELL_KEY && type == WT_PAGE_ROW_LEAF) {
 		++p;					/* skip prefix */
 		WT_CELL_LEN_CHK(p, 0);
 		unpack->prefix = cell->__chunk[1];
@@ -614,9 +650,9 @@ done:	WT_CELL_LEN_CHK(cell, unpack->__len);
  *	Unpack a WT_CELL into a structure.
  */
 static inline void
-__wt_cell_unpack(WT_CELL *cell, WT_CELL_UNPACK *unpack)
+__wt_cell_unpack(WT_CELL *cell, int type, WT_CELL_UNPACK *unpack)
 {
-	(void)__wt_cell_unpack_safe(cell, unpack, NULL);
+	(void)__wt_cell_unpack_safe(cell, type, unpack, NULL);
 }
 
 /*