Add statistics to show just how much prefix/suffix compression are

buying us.

4 files changed, 26 insertions, 5 deletions

diff --git a/src/btree/rec_write.c b/src/btree/rec_write.c
index 92da02c268e..2524ec9ccfd 100644
--- a/src/btree/rec_write.c
+++ b/src/btree/rec_write.c
@@ -1437,7 +1437,11 @@ __rec_split_row_promote(WT_SESSION_IMPL *session, WT_RECONCILE *r, uint8_t type)
 		size = len + 1;
 		for (cnt = 1; len > 0; ++cnt, --len, ++pa, ++pb)
 			if (*pa != *pb) {
-				size = cnt;
+				if (size != cnt) {
+					WT_STAT_FAST_DATA_INCRV(session,
+					    rec_suffix_compression, size - cnt);
+					size = cnt;
+				}
 				break;
 			}
 	} else
@@ -4455,6 +4459,9 @@ __rec_cell_build_leaf_key(WT_SESSION_IMPL *session,
 			 */
 			if (pfx < btree->prefix_compression_min)
 				pfx = 0;
+			else
+				WT_STAT_FAST_DATA_INCRV(
+				    session, rec_prefix_compression, pfx);
 		}
 
 		/* Copy the non-prefix bytes into the key buffer. */
diff --git a/src/include/stat.h b/src/include/stat.h
index 63db0e65d52..e00b9ee40db 100644
--- a/src/include/stat.h
+++ b/src/include/stat.h
@@ -287,7 +287,9 @@ struct __wt_dsrc_stats {
 	WT_STATS rec_page_match;
 	WT_STATS rec_pages;
 	WT_STATS rec_pages_eviction;
+	WT_STATS rec_prefix_compression;
 	WT_STATS rec_skipped_update;
+	WT_STATS rec_suffix_compression;
 	WT_STATS session_compact;
 	WT_STATS session_cursor_open;
 	WT_STATS txn_update_conflict;
diff --git a/src/include/wiredtiger.in b/src/include/wiredtiger.in
index a78edd61983..20c1466dff2 100644
--- a/src/include/wiredtiger.in
+++ b/src/include/wiredtiger.in
@@ -2943,14 +2943,18 @@ extern int wiredtiger_extension_terminate(WT_CONNECTION *connection);
 #define	WT_STAT_DSRC_REC_PAGES				2078
 /*! page reconciliation calls for eviction */
 #define	WT_STAT_DSRC_REC_PAGES_EVICTION			2079
+/*! leaf page key bytes discarded using prefix compression */
+#define	WT_STAT_DSRC_REC_PREFIX_COMPRESSION		2080
 /*! reconciliation failed because an update could not be included */
-#define	WT_STAT_DSRC_REC_SKIPPED_UPDATE			2080
+#define	WT_STAT_DSRC_REC_SKIPPED_UPDATE			2081
+/*! internal page key bytes discarded using suffix compression */
+#define	WT_STAT_DSRC_REC_SUFFIX_COMPRESSION		2082
 /*! object compaction */
-#define	WT_STAT_DSRC_SESSION_COMPACT			2081
+#define	WT_STAT_DSRC_SESSION_COMPACT			2083
 /*! open cursor count */
-#define	WT_STAT_DSRC_SESSION_CURSOR_OPEN		2082
+#define	WT_STAT_DSRC_SESSION_CURSOR_OPEN		2084
 /*! update conflicts */
-#define	WT_STAT_DSRC_TXN_UPDATE_CONFLICT		2083
+#define	WT_STAT_DSRC_TXN_UPDATE_CONFLICT		2085
 /*! @} */
 /*
  * Statistics section: END
diff --git a/src/support/stat.c b/src/support/stat.c
index 6fb7de125a9..7a52b3c5a90 100644
--- a/src/support/stat.c
+++ b/src/support/stat.c
@@ -111,8 +111,12 @@ __wt_stat_init_dsrc_stats(WT_DSRC_STATS *stats)
 	stats->rec_pages.desc = "page reconciliation calls";
 	stats->rec_pages_eviction.desc =
 	    "page reconciliation calls for eviction";
+	stats->rec_prefix_compression.desc =
+	    "leaf page key bytes discarded using prefix compression";
 	stats->rec_skipped_update.desc =
 	    "reconciliation failed because an update could not be included";
+	stats->rec_suffix_compression.desc =
+	    "internal page key bytes discarded using suffix compression";
 	stats->session_compact.desc = "object compaction";
 	stats->session_cursor_open.desc = "open cursor count";
 	stats->txn_update_conflict.desc = "update conflicts";
@@ -204,7 +208,9 @@ __wt_stat_refresh_dsrc_stats(void *stats_arg)
 	stats->rec_page_match.v = 0;
 	stats->rec_pages.v = 0;
 	stats->rec_pages_eviction.v = 0;
+	stats->rec_prefix_compression.v = 0;
 	stats->rec_skipped_update.v = 0;
+	stats->rec_suffix_compression.v = 0;
 	stats->session_compact.v = 0;
 	stats->txn_update_conflict.v = 0;
 }
@@ -289,7 +295,9 @@ __wt_stat_aggregate_dsrc_stats(const void *child, const void *parent)
 	p->rec_page_match.v += c->rec_page_match.v;
 	p->rec_pages.v += c->rec_pages.v;
 	p->rec_pages_eviction.v += c->rec_pages_eviction.v;
+	p->rec_prefix_compression.v += c->rec_prefix_compression.v;
 	p->rec_skipped_update.v += c->rec_skipped_update.v;
+	p->rec_suffix_compression.v += c->rec_suffix_compression.v;
 	p->session_compact.v += c->session_compact.v;
 	p->session_cursor_open.v += c->session_cursor_open.v;
 	p->txn_update_conflict.v += c->txn_update_conflict.v;