WT-2975 Only allocate space for statistics when we open a data source (#3107)

8 files changed, 64 insertions, 28 deletions

diff --git a/src/conn/conn_dhandle.c b/src/conn/conn_dhandle.c
index ec850c793cc..30d901c9b64 100644
--- a/src/conn/conn_dhandle.c
+++ b/src/conn/conn_dhandle.c
@@ -20,6 +20,7 @@ __conn_dhandle_destroy(WT_SESSION_IMPL *session, WT_DATA_HANDLE *dhandle)
 	__wt_free(session, dhandle->checkpoint);
 	__wt_free(session, dhandle->handle);
 	__wt_spin_destroy(session, &dhandle->close_lock);
+	__wt_stat_dsrc_discard(session, dhandle);
 	__wt_overwrite_and_free(session, dhandle);
 }
 
@@ -54,8 +55,6 @@ __conn_dhandle_alloc(WT_SESSION_IMPL *session,
 	WT_ERR(__wt_spin_init(
 	    session, &dhandle->close_lock, "data handle close"));
 
-	__wt_stat_dsrc_init(dhandle);
-
 	if (strcmp(uri, WT_METAFILE_URI) == 0)
 		F_SET(dhandle, WT_DHANDLE_IS_METADATA);
 
@@ -310,16 +309,15 @@ __wt_conn_btree_open(
 	WT_ASSERT(session, !F_ISSET(S2C(session), WT_CONN_CLOSING));
 
 	/*
-	 * If the handle is already open, it has to be closed so it can
-	 * be reopened with a new configuration.
+	 * If the handle is already open, it has to be closed so it can be
+	 * reopened with a new configuration.
 	 *
-	 * This call can return EBUSY if there's an update in the
-	 * object that's not yet globally visible.  That's not a
-	 * problem because it can only happen when we're switching from
-	 * a normal handle to a "special" one, so we're returning EBUSY
-	 * to an attempt to verify or do other special operations.  The
-	 * reverse won't happen because when the handle from a verify
-	 * or other special operation is closed, there won't be updates
+	 * This call can return EBUSY if there's an update in the object that's
+	 * not yet globally visible. That's not a problem because it can only
+	 * happen when we're switching from a normal handle to a "special" one,
+	 * so we're returning EBUSY to an attempt to verify or do other special
+	 * operations. The reverse won't happen because when the handle from a
+	 * verify or other special operation is closed, there won't be updates
 	 * in the tree that can block the close.
 	 */
 	if (F_ISSET(dhandle, WT_DHANDLE_OPEN))
@@ -332,6 +330,16 @@ __wt_conn_btree_open(
 	/* Set any special flags on the handle. */
 	F_SET(btree, LF_MASK(WT_BTREE_SPECIAL_FLAGS));
 
+	/*
+	 * Allocate data-source statistics memory. We don't allocate that memory
+	 * when allocating the data-handle because not all data handles need
+	 * statistics (for example, handles used for checkpoint locking). If we
+	 * are reopening the handle, then it may already have statistics memory,
+	 * check to avoid the leak.
+	 */
+	if (!F_ISSET(dhandle, WT_DHANDLE_OPEN))
+		WT_ERR(__wt_stat_dsrc_init(session, dhandle));
+
 	WT_ERR(__wt_btree_open(session, cfg));
 
 	/*
@@ -554,8 +562,7 @@ __wt_conn_dhandle_discard_single(
 
 	dhandle = session->dhandle;
 
-	if (F_ISSET(dhandle, WT_DHANDLE_OPEN) ||
-	    (final && F_ISSET(dhandle, WT_DHANDLE_DEAD))) {
+	if (F_ISSET(dhandle, WT_DHANDLE_OPEN)) {
 		tret = __wt_conn_btree_sync_and_close(session, final, force);
 		if (final && tret != 0) {
 			__wt_err(session, tret,
diff --git a/src/conn/conn_handle.c b/src/conn/conn_handle.c
index 5104624523b..3571cc60115 100644
--- a/src/conn/conn_handle.c
+++ b/src/conn/conn_handle.c
@@ -48,7 +48,7 @@ __wt_connection_init(WT_CONNECTION_IMPL *conn)
 	WT_RET(__wt_conn_config_init(session));
 
 	/* Statistics. */
-	__wt_stat_connection_init(conn);
+	WT_RET(__wt_stat_connection_init(session, conn));
 
 	/* Spinlocks. */
 	WT_RET(__wt_spin_init(session, &conn->api_lock, "api"));
@@ -161,6 +161,7 @@ __wt_connection_destroy(WT_CONNECTION_IMPL *conn)
 	__wt_free(session, conn->home);
 	__wt_free(session, conn->error_prefix);
 	__wt_free(session, conn->sessions);
+	__wt_stat_connection_discard(session, conn);
 
 	__wt_free(NULL, conn);
 	return (ret);
diff --git a/src/include/connection.h b/src/include/connection.h
index 88c672ea49b..4e8e88bf6e4 100644
--- a/src/include/connection.h
+++ b/src/include/connection.h
@@ -290,7 +290,7 @@ struct __wt_connection_impl {
 
 					/* Connection statistics */
 	WT_CONNECTION_STATS *stats[WT_COUNTER_SLOTS];
-	WT_CONNECTION_STATS  stat_array[WT_COUNTER_SLOTS];
+	WT_CONNECTION_STATS *stat_array;
 
 	WT_ASYNC	*async;		/* Async structure */
 	int		 async_cfg;	/* Global async configuration */
diff --git a/src/include/dhandle.h b/src/include/dhandle.h
index 9a11594c893..001eb268f86 100644
--- a/src/include/dhandle.h
+++ b/src/include/dhandle.h
@@ -75,7 +75,7 @@ struct __wt_data_handle {
 
 					/* Data-source statistics */
 	WT_DSRC_STATS *stats[WT_COUNTER_SLOTS];
-	WT_DSRC_STATS  stat_array[WT_COUNTER_SLOTS];
+	WT_DSRC_STATS *stat_array;
 
 	/* Flags values over 0xff are reserved for WT_BTREE_* */
 #define	WT_DHANDLE_DEAD		        0x01	/* Dead, awaiting discard */
diff --git a/src/include/extern.h b/src/include/extern.h
index 84cd1b6aa8c..da5f78bb526 100644
--- a/src/include/extern.h
+++ b/src/include/extern.h
@@ -697,14 +697,16 @@ extern void *__wt_ext_scr_alloc( WT_EXTENSION_API *wt_api, WT_SESSION *wt_sessio
 extern void __wt_ext_scr_free(WT_EXTENSION_API *wt_api, WT_SESSION *wt_session, void *p);
 extern int __wt_stat_dsrc_desc(WT_CURSOR_STAT *cst, int slot, const char **p) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern void __wt_stat_dsrc_init_single(WT_DSRC_STATS *stats);
-extern void __wt_stat_dsrc_init(WT_DATA_HANDLE *handle);
+extern int __wt_stat_dsrc_init( WT_SESSION_IMPL *session, WT_DATA_HANDLE *handle) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern void __wt_stat_dsrc_discard( WT_SESSION_IMPL *session, WT_DATA_HANDLE *handle);
 extern void __wt_stat_dsrc_clear_single(WT_DSRC_STATS *stats);
 extern void __wt_stat_dsrc_clear_all(WT_DSRC_STATS **stats);
 extern void __wt_stat_dsrc_aggregate_single( WT_DSRC_STATS *from, WT_DSRC_STATS *to);
 extern void __wt_stat_dsrc_aggregate( WT_DSRC_STATS **from, WT_DSRC_STATS *to);
 extern int __wt_stat_connection_desc(WT_CURSOR_STAT *cst, int slot, const char **p) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern void __wt_stat_connection_init_single(WT_CONNECTION_STATS *stats);
-extern void __wt_stat_connection_init(WT_CONNECTION_IMPL *handle);
+extern int __wt_stat_connection_init( WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *handle) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern void __wt_stat_connection_discard( WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *handle);
 extern void __wt_stat_connection_clear_single(WT_CONNECTION_STATS *stats);
 extern void __wt_stat_connection_clear_all(WT_CONNECTION_STATS **stats);
 extern void __wt_stat_connection_aggregate( WT_CONNECTION_STATS **from, WT_CONNECTION_STATS *to);
diff --git a/src/include/meta.h b/src/include/meta.h
index 63c79dbc72e..6d4a167a8e5 100644
--- a/src/include/meta.h
+++ b/src/include/meta.h
@@ -29,9 +29,8 @@
 #define	WT_LAS_URI		"file:WiredTigerLAS.wt"	/* Lookaside table URI*/
 
 /*
- * Pre computed hash for the metadata file. Used to optimize comparisons
- * against the metafile URI. The validity is checked on connection open
- * when diagnostic is enabled.
+ * Optimize comparisons against the metafile URI, flag handles that reference
+ * the metadata file.
  */
 #define	WT_IS_METADATA(session, dh)					\
 	F_ISSET((dh), WT_DHANDLE_IS_METADATA)
diff --git a/src/include/stat.h b/src/include/stat.h
index d0b0b60585a..e53414fc0c9 100644
--- a/src/include/stat.h
+++ b/src/include/stat.h
@@ -225,21 +225,24 @@ __wt_stats_clear(void *stats_arg, int slot)
  * necessary until everything is converted to using data-source handles.
  */
 #define	WT_STAT_DATA_DECRV(session, fld, value) do {			\
-	if ((session)->dhandle != NULL)					\
+	if ((session)->dhandle != NULL &&				\
+	    (session)->dhandle->stat_array != NULL)			\
 		WT_STAT_DECRV(						\
 		    session, (session)->dhandle->stats, fld, value);	\
 } while (0)
 #define	WT_STAT_DATA_DECR(session, fld)					\
 	WT_STAT_DATA_DECRV(session, fld, 1)
 #define	WT_STAT_DATA_INCRV(session, fld, value) do {			\
-	if ((session)->dhandle != NULL)					\
+	if ((session)->dhandle != NULL &&				\
+	    (session)->dhandle->stat_array != NULL)			\
 		WT_STAT_INCRV(						\
 		    session, (session)->dhandle->stats, fld, value);	\
 } while (0)
 #define	WT_STAT_DATA_INCR(session, fld)					\
 	WT_STAT_DATA_INCRV(session, fld, 1)
 #define	WT_STAT_DATA_SET(session, fld, value) do {			\
-	if ((session)->dhandle != NULL)					\
+	if ((session)->dhandle != NULL &&				\
+	    (session)->dhandle->stat_array != NULL)			\
 		WT_STAT_SET(						\
 		    session, (session)->dhandle->stats, fld, value);	\
 } while (0)
diff --git a/src/support/stat.c b/src/support/stat.c
index 6e8e218a0db..5acd9fc713f 100644
--- a/src/support/stat.c
+++ b/src/support/stat.c
@@ -138,15 +138,27 @@ __wt_stat_dsrc_init_single(WT_DSRC_STATS *stats)
 	memset(stats, 0, sizeof(*stats));
 }
 
-void
-__wt_stat_dsrc_init(WT_DATA_HANDLE *handle)
+int
+__wt_stat_dsrc_init(
+    WT_SESSION_IMPL *session, WT_DATA_HANDLE *handle)
 {
 	int i;
 
+	WT_RET(__wt_calloc(session, (size_t)WT_COUNTER_SLOTS,
+	    sizeof(*handle->stat_array), &handle->stat_array));
+
 	for (i = 0; i < WT_COUNTER_SLOTS; ++i) {
 		handle->stats[i] = &handle->stat_array[i];
 		__wt_stat_dsrc_init_single(handle->stats[i]);
 	}
+	return (0);
+}
+
+void
+__wt_stat_dsrc_discard(
+    WT_SESSION_IMPL *session, WT_DATA_HANDLE *handle)
+{
+	__wt_free(session, handle->stat_array);
 }
 
 void
@@ -860,15 +872,27 @@ __wt_stat_connection_init_single(WT_CONNECTION_STATS *stats)
 	memset(stats, 0, sizeof(*stats));
 }
 
-void
-__wt_stat_connection_init(WT_CONNECTION_IMPL *handle)
+int
+__wt_stat_connection_init(
+    WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *handle)
 {
 	int i;
 
+	WT_RET(__wt_calloc(session, (size_t)WT_COUNTER_SLOTS,
+	    sizeof(*handle->stat_array), &handle->stat_array));
+
 	for (i = 0; i < WT_COUNTER_SLOTS; ++i) {
 		handle->stats[i] = &handle->stat_array[i];
 		__wt_stat_connection_init_single(handle->stats[i]);
 	}
+	return (0);
+}
+
+void
+__wt_stat_connection_discard(
+    WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *handle)
+{
+	__wt_free(session, handle->stat_array);
 }
 
 void