WT-2711 Change statistics log configuration options (#2834)

No longer support setting the statistics_log path in WT_CONNECTION::reconfigure.
No longer support setting a custom name for statistics files, only allow a destination directory.
Be more explicit about which logging configuration options are allowed in WT_CONNECTION::reconfigure.

The aim of these changes is to avoid situations where applications that embed WiredTiger allow their users to overwrite unexpected files on a file system.

This potentially requires an upgrade step for applications that were specifying a non-standard file name component for statistics log file names, it's not backward compatible.
(cherry picked from commit 9cc5d0f4b18753c6cd5cfcfda11a4e3fa7505d9e)

18 files changed, 436 insertions, 294 deletions

diff --git a/dist/api_data.py b/dist/api_data.py
index 90b1c8378a2..0d995a3e2e2 100644
--- a/dist/api_data.py
+++ b/dist/api_data.py
@@ -420,40 +420,6 @@ connection_runtime_config = [
             interval in seconds at which to check for files that are
             inactive and close them''', min=1, max=100000),
         ]),
-    Config('log', '', r'''
-        enable logging. Enabling logging uses three sessions from the
-        configured session_max''',
-        type='category', subconfig=[
-        Config('archive', 'true', r'''
-            automatically archive unneeded log files''',
-            type='boolean'),
-        Config('compressor', 'none', r'''
-            configure a compressor for log records.  Permitted values are
-            \c "none" or custom compression engine name created with
-            WT_CONNECTION::add_compressor.  If WiredTiger has builtin support
-            for \c "snappy", \c "lz4" or \c "zlib" compression, these names
-            are also available. See @ref compression for more information'''),
-        Config('enabled', 'false', r'''
-            enable logging subsystem''',
-            type='boolean'),
-        Config('file_max', '100MB', r'''
-            the maximum size of log files''',
-            min='100KB', max='2GB'),
-        Config('path', '"."', r'''
-            the path to a directory into which the log files are written.
-            If the value is not an absolute path name, the files are created
-            relative to the database home'''),
-        Config('prealloc', 'true', r'''
-            pre-allocate log files.''',
-            type='boolean'),
-        Config('recover', 'on', r'''
-            run recovery or error if recovery needs to run after an
-            unclean shutdown.''',
-            choices=['error','on']),
-        Config('zero_fill', 'false', r'''
-            manually write zeroes into log files''',
-            type='boolean'),
-        ]),
     Config('lsm_manager', '', r'''
         configure database wide options for LSM tree management. The LSM
         manager is started automatically the first time an LSM tree is opened.
@@ -525,38 +491,6 @@ connection_runtime_config = [
         are logged using the \c statistics_log configuration.  See
         @ref statistics for more information''',
         type='list', choices=['all', 'fast', 'none', 'clear']),
-    Config('statistics_log', '', r'''
-        log any statistics the database is configured to maintain,
-        to a file.  See @ref statistics for more information. Enabling
-        the statistics log server uses a session from the configured
-        session_max''',
-        type='category', subconfig=[
-        Config('json', 'false', r'''
-            encode statistics in JSON format''',
-            type='boolean'),
-        Config('on_close', 'false', r'''log statistics on database close''',
-            type='boolean'),
-        Config('path', '"WiredTigerStat.%d.%H"', r'''
-            the pathname to a file into which the log records are written,
-            may contain ISO C standard strftime conversion specifications.
-            If the value is not an absolute path name, the file is created
-            relative to the database home'''),
-        Config('sources', '', r'''
-            if non-empty, include statistics for the list of data source
-            URIs, if they are open at the time of the statistics logging.
-            The list may include URIs matching a single data source
-            ("table:mytable"), or a URI matching all data sources of a
-            particular type ("table:")''',
-            type='list'),
-        Config('timestamp', '"%b %d %H:%M:%S"', r'''
-            a timestamp prepended to each log record, may contain strftime
-            conversion specifications, when \c json is configured, defaults
-            to \c "%FT%Y.000Z"'''),
-        Config('wait', '0', r'''
-            seconds to wait between each write of the log records; setting
-            this value above 0 configures statistics logging''',
-            min='0', max='100000'),
-        ]),
     Config('verbose', '', r'''
         enable messages for various events. Only available if WiredTiger
         is configured with --enable-verbose. Options are given as a
@@ -590,13 +524,113 @@ connection_runtime_config = [
             'write']),
 ]
 
+# wiredtiger_open and WT_CONNECTION.reconfigure log configurations.
+log_configuration_common = [
+    Config('archive', 'true', r'''
+        automatically archive unneeded log files''',
+        type='boolean'),
+    Config('prealloc', 'true', r'''
+        pre-allocate log files.''',
+        type='boolean'),
+    Config('zero_fill', 'false', r'''
+        manually write zeroes into log files''',
+        type='boolean')
+]
+connection_reconfigure_log_configuration = [
+    Config('log', '', r'''
+        enable logging. Enabling logging uses three sessions from the
+        configured session_max''',
+        type='category', subconfig=
+        log_configuration_common)
+]
+wiredtiger_open_log_configuration = [
+    Config('log', '', r'''
+        enable logging. Enabling logging uses three sessions from the
+        configured session_max''',
+        type='category', subconfig=
+        log_configuration_common + [
+        Config('enabled', 'false', r'''
+            enable logging subsystem''',
+            type='boolean'),
+        Config('compressor', 'none', r'''
+            configure a compressor for log records.  Permitted values are
+            \c "none" or custom compression engine name created with
+            WT_CONNECTION::add_compressor.  If WiredTiger has builtin support
+            for \c "snappy", \c "lz4" or \c "zlib" compression, these names
+            are also available. See @ref compression for more information'''),
+        Config('file_max', '100MB', r'''
+            the maximum size of log files''',
+            min='100KB', max='2GB'),
+            Config('path', '"."', r'''
+                the name of a directory into which log files are written. The
+                directory must already exist. If the value is not an absolute
+                path, the path is relative to the database home (see @ref
+                absolute_path for more information)'''),
+        Config('recover', 'on', r'''
+            run recovery or error if recovery needs to run after an
+            unclean shutdown''',
+            choices=['error','on'])
+    ]),
+]
+
+# wiredtiger_open and WT_CONNECTION.reconfigure statistics log configurations.
+statistics_log_configuration_common = [
+    Config('json', 'false', r'''
+        encode statistics in JSON format''',
+        type='boolean'),
+    Config('on_close', 'false', r'''log statistics on database close''',
+        type='boolean'),
+    Config('sources', '', r'''
+        if non-empty, include statistics for the list of data source
+        URIs, if they are open at the time of the statistics logging.
+        The list may include URIs matching a single data source
+        ("table:mytable"), or a URI matching all data sources of a
+        particular type ("table:")''',
+        type='list'),
+    Config('timestamp', '"%b %d %H:%M:%S"', r'''
+        a timestamp prepended to each log record, may contain strftime
+        conversion specifications, when \c json is configured, defaults
+        to \c "%FT%Y.000Z"'''),
+    Config('wait', '0', r'''
+        seconds to wait between each write of the log records; setting
+        this value above 0 configures statistics logging''',
+        min='0', max='100000'),
+]
+connection_reconfigure_statistics_log_configuration = [
+    Config('statistics_log', '', r'''
+        log any statistics the database is configured to maintain,
+        to a file.  See @ref statistics for more information. Enabling
+        the statistics log server uses a session from the configured
+        session_max''',
+        type='category', subconfig=
+        statistics_log_configuration_common)
+]
+wiredtiger_open_statistics_log_configuration = [
+    Config('statistics_log', '', r'''
+        log any statistics the database is configured to maintain,
+        to a file.  See @ref statistics for more information. Enabling
+        the statistics log server uses a session from the configured
+        session_max''',
+        type='category', subconfig=
+        statistics_log_configuration_common + [
+        Config('path', '"."', r'''
+            the name of a directory into which statistics files are written.
+            The directory must already exist. If the value is not an absolute
+            path, the path is relative to the database home (see @ref
+            absolute_path for more information)''')
+        ])
+]
+
 session_config = [
     Config('isolation', 'read-committed', r'''
         the default isolation level for operations in this session''',
         choices=['read-uncommitted', 'read-committed', 'snapshot']),
 ]
 
-wiredtiger_open_common = connection_runtime_config + [
+wiredtiger_open_common =\
+    connection_runtime_config +\
+    wiredtiger_open_log_configuration +\
+    wiredtiger_open_statistics_log_configuration + [
     Config('buffer_alignment', '-1', r'''
         in-memory alignment (in bytes) for buffers used for I/O.  The
         default value of -1 indicates a platform-specific alignment value
@@ -1084,7 +1118,11 @@ methods = {
         don't free memory during close''',
         type='boolean'),
 ]),
-'WT_CONNECTION.reconfigure' : Method(connection_runtime_config),
+'WT_CONNECTION.reconfigure' : Method(
+    connection_reconfigure_log_configuration +\
+    connection_reconfigure_statistics_log_configuration +\
+    connection_runtime_config
+),
 'WT_CONNECTION.set_file_system' : Method([]),
 
 'WT_CONNECTION.load_extension' : Method([
diff --git a/dist/s_string.ok b/dist/s_string.ok
index 7966ff2cf2e..85ccf9f95c7 100644
--- a/dist/s_string.ok
+++ b/dist/s_string.ok
@@ -326,6 +326,7 @@ UID
 UIDs
 UINT
 ULINE
+UNC
 URI
 URIs
 UTF
@@ -557,6 +558,7 @@ dequeued
 der
 dereference
 desc
+designator
 dest
 destSize
 dev
@@ -1065,6 +1067,7 @@ tV
 tablename
 tcbench
 td
+tempdir
 testutil
 th
 tid
@@ -1091,6 +1094,7 @@ txn
 txnc
 txnid
 txnmin
+txt
 typedef
 uB
 uS
diff --git a/examples/c/ex_all.c b/examples/c/ex_all.c
index dd807922c10..e8727df3f60 100644
--- a/examples/c/ex_all.c
+++ b/examples/c/ex_all.c
@@ -1160,34 +1160,27 @@ main(void)
 	if (ret == 0)
 		(void)conn->close(conn, NULL);
 
+#ifdef MIGHT_NOT_RUN
+	/*
+	 * Don't run this code, statistics logging doesn't yet support tables.
+	 */
 	/*! [Statistics logging with a table] */
 	ret = wiredtiger_open(home, NULL,
 	    "create, statistics_log=("
-	    "sources=(\"lsm:table1\",\"lsm:table2\"), wait=5)",
+	    "sources=(\"table:table1\",\"table:table2\"), wait=5)",
 	    &conn);
 	/*! [Statistics logging with a table] */
 	if (ret == 0)
 		(void)conn->close(conn, NULL);
 
-	/*! [Statistics logging with all tables] */
-	ret = wiredtiger_open(home, NULL,
-	    "create, statistics_log=(sources=(\"lsm:\"), wait=5)",
-	    &conn);
-	/*! [Statistics logging with all tables] */
-	if (ret == 0)
-		(void)conn->close(conn, NULL);
-
-#ifdef MIGHT_NOT_RUN
 	/*
-	 * This example code gets run, and a non-existent log file path might
-	 * cause the open to fail.  The documentation requires code snippets,
-	 * use #ifdef's to avoid running it.
+	 * Don't run this code, statistics logging doesn't yet support indexes.
 	 */
-	/*! [Statistics logging with path] */
+	/*! [Statistics logging with a source type] */
 	ret = wiredtiger_open(home, NULL,
-	    "create,"
-	    "statistics_log=(wait=120,path=/log/log.%m.%d.%y)", &conn);
-	/*! [Statistics logging with path] */
+	    "create, statistics_log=(sources=(\"index:\"), wait=5)",
+	    &conn);
+	/*! [Statistics logging with a source type] */
 	if (ret == 0)
 		(void)conn->close(conn, NULL);
 
diff --git a/examples/java/com/wiredtiger/examples/ex_all.java b/examples/java/com/wiredtiger/examples/ex_all.java
index 48e85c9fade..83a37e9a6a5 100644
--- a/examples/java/com/wiredtiger/examples/ex_all.java
+++ b/examples/java/com/wiredtiger/examples/ex_all.java
@@ -988,6 +988,10 @@ allExample()
     /*! [Statistics logging] */
     conn.close(null);
 
+    if (false) {  // MIGHT_NOT_RUN
+    /*
+     * Don't run this code, statistics logging doesn't yet support tables.
+     */
     /*! [Statistics logging with a table] */
     conn = wiredtiger.open(home,
         "create," +
@@ -995,23 +999,13 @@ allExample()
     /*! [Statistics logging with a table] */
     conn.close(null);
 
-    /*! [Statistics logging with all tables] */
-    conn = wiredtiger.open(home,
-        "create,statistics_log=(sources=(\"table:\"))");
-    /*! [Statistics logging with all tables] */
-    conn.close(null);
-
-    if (false) {  // MIGHT_NOT_RUN
     /*
-     * This example code gets run, and a non-existent log file path might
-     * cause the open to fail.  The documentation requires code snippets,
-     * use if (false) to avoid running it.
+     * Don't run this code, statistics logging doesn't yet support indexes.
      */
-    /*! [Statistics logging with path] */
+    /*! [Statistics logging with a source type] */
     conn = wiredtiger.open(home,
-        "create," +
-        "statistics_log=(wait=120,path=/log/log.%m.%d.%y)");
-    /*! [Statistics logging with path] */
+        "create,statistics_log=(sources=(\"index:\"))");
+    /*! [Statistics logging with a source type] */
     conn.close(null);
 
     /*
diff --git a/src/config/config_def.c b/src/config/config_def.c
index 1b656c5a0aa..352464ee92a 100644
--- a/src/config/config_def.c
+++ b/src/config/config_def.c
@@ -67,16 +67,9 @@ static const WT_CONFIG_CHECK
 };
 
 static const WT_CONFIG_CHECK
-    confchk_wiredtiger_open_log_subconfigs[] = {
+    confchk_WT_CONNECTION_reconfigure_log_subconfigs[] = {
 	{ "archive", "boolean", NULL, NULL, NULL, 0 },
-	{ "compressor", "string", NULL, NULL, NULL, 0 },
-	{ "enabled", "boolean", NULL, NULL, NULL, 0 },
-	{ "file_max", "int", NULL, "min=100KB,max=2GB", NULL, 0 },
-	{ "path", "string", NULL, NULL, NULL, 0 },
 	{ "prealloc", "boolean", NULL, NULL, NULL, 0 },
-	{ "recover", "string",
-	    NULL, "choices=[\"error\",\"on\"]",
-	    NULL, 0 },
 	{ "zero_fill", "boolean", NULL, NULL, NULL, 0 },
 	{ NULL, NULL, NULL, NULL, NULL, 0 }
 };
@@ -99,10 +92,9 @@ static const WT_CONFIG_CHECK
 };
 
 static const WT_CONFIG_CHECK
-    confchk_wiredtiger_open_statistics_log_subconfigs[] = {
+    confchk_WT_CONNECTION_reconfigure_statistics_log_subconfigs[] = {
 	{ "json", "boolean", NULL, NULL, NULL, 0 },
 	{ "on_close", "boolean", NULL, NULL, NULL, 0 },
-	{ "path", "string", NULL, NULL, NULL, 0 },
 	{ "sources", "list", NULL, NULL, NULL, 0 },
 	{ "timestamp", "string", NULL, NULL, NULL, 0 },
 	{ "wait", "int", NULL, "min=0,max=100000", NULL, 0 },
@@ -135,7 +127,7 @@ static const WT_CONFIG_CHECK confchk_WT_CONNECTION_reconfigure[] = {
 	    confchk_wiredtiger_open_file_manager_subconfigs, 3 },
 	{ "log", "category",
 	    NULL, NULL,
-	    confchk_wiredtiger_open_log_subconfigs, 8 },
+	    confchk_WT_CONNECTION_reconfigure_log_subconfigs, 3 },
 	{ "lsm_manager", "category",
 	    NULL, NULL,
 	    confchk_wiredtiger_open_lsm_manager_subconfigs, 2 },
@@ -148,7 +140,7 @@ static const WT_CONFIG_CHECK confchk_WT_CONNECTION_reconfigure[] = {
 	    NULL, 0 },
 	{ "statistics_log", "category",
 	    NULL, NULL,
-	    confchk_wiredtiger_open_statistics_log_subconfigs, 6 },
+	    confchk_WT_CONNECTION_reconfigure_statistics_log_subconfigs, 5 },
 	{ "verbose", "list",
 	    NULL, "choices=[\"api\",\"block\",\"checkpoint\",\"compact\","
 	    "\"evict\",\"evictserver\",\"fileops\",\"handleops\",\"log\","
@@ -608,6 +600,32 @@ static const WT_CONFIG_CHECK
 };
 
 static const WT_CONFIG_CHECK
+    confchk_wiredtiger_open_log_subconfigs[] = {
+	{ "archive", "boolean", NULL, NULL, NULL, 0 },
+	{ "compressor", "string", NULL, NULL, NULL, 0 },
+	{ "enabled", "boolean", NULL, NULL, NULL, 0 },
+	{ "file_max", "int", NULL, "min=100KB,max=2GB", NULL, 0 },
+	{ "path", "string", NULL, NULL, NULL, 0 },
+	{ "prealloc", "boolean", NULL, NULL, NULL, 0 },
+	{ "recover", "string",
+	    NULL, "choices=[\"error\",\"on\"]",
+	    NULL, 0 },
+	{ "zero_fill", "boolean", NULL, NULL, NULL, 0 },
+	{ NULL, NULL, NULL, NULL, NULL, 0 }
+};
+
+static const WT_CONFIG_CHECK
+    confchk_wiredtiger_open_statistics_log_subconfigs[] = {
+	{ "json", "boolean", NULL, NULL, NULL, 0 },
+	{ "on_close", "boolean", NULL, NULL, NULL, 0 },
+	{ "path", "string", NULL, NULL, NULL, 0 },
+	{ "sources", "list", NULL, NULL, NULL, 0 },
+	{ "timestamp", "string", NULL, NULL, NULL, 0 },
+	{ "wait", "int", NULL, "min=0,max=100000", NULL, 0 },
+	{ NULL, NULL, NULL, NULL, NULL, 0 }
+};
+
+static const WT_CONFIG_CHECK
     confchk_wiredtiger_open_transaction_sync_subconfigs[] = {
 	{ "enabled", "boolean", NULL, NULL, NULL, 0 },
 	{ "method", "string",
@@ -975,12 +993,10 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  "eviction=(threads_max=1,threads_min=1),eviction_dirty_target=80,"
 	  "eviction_dirty_trigger=95,eviction_target=80,eviction_trigger=95"
 	  ",file_manager=(close_handle_minimum=250,close_idle_time=30,"
-	  "close_scan_interval=10),log=(archive=,compressor=,enabled=0,"
-	  "file_max=100MB,path=\".\",prealloc=,recover=on,zero_fill=0),"
+	  "close_scan_interval=10),log=(archive=,prealloc=,zero_fill=0),"
 	  "lsm_manager=(merge=,worker_thread_max=4),lsm_merge=,"
 	  "shared_cache=(chunk=10MB,name=,quota=0,reserve=0,size=500MB),"
-	  "statistics=none,statistics_log=(json=0,on_close=0,"
-	  "path=\"WiredTigerStat.%d.%H\",sources=,"
+	  "statistics=none,statistics_log=(json=0,on_close=0,sources=,"
 	  "timestamp=\"%b %d %H:%M:%S\",wait=0),verbose=",
 	  confchk_WT_CONNECTION_reconfigure, 18
 	},
@@ -1181,11 +1197,10 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  ",worker_thread_max=4),lsm_merge=,mmap=,multiprocess=0,readonly=0"
 	  ",session_max=100,session_scratch_max=2MB,"
 	  "shared_cache=(chunk=10MB,name=,quota=0,reserve=0,size=500MB),"
-	  "statistics=none,statistics_log=(json=0,on_close=0,"
-	  "path=\"WiredTigerStat.%d.%H\",sources=,"
-	  "timestamp=\"%b %d %H:%M:%S\",wait=0),transaction_sync=(enabled=0"
-	  ",method=fsync),use_environment=,use_environment_priv=0,verbose=,"
-	  "write_through=",
+	  "statistics=none,statistics_log=(json=0,on_close=0,path=\".\","
+	  "sources=,timestamp=\"%b %d %H:%M:%S\",wait=0),"
+	  "transaction_sync=(enabled=0,method=fsync),use_environment=,"
+	  "use_environment_priv=0,verbose=,write_through=",
 	  confchk_wiredtiger_open, 38
 	},
 	{ "wiredtiger_open_all",
@@ -1203,11 +1218,11 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  ",worker_thread_max=4),lsm_merge=,mmap=,multiprocess=0,readonly=0"
 	  ",session_max=100,session_scratch_max=2MB,"
 	  "shared_cache=(chunk=10MB,name=,quota=0,reserve=0,size=500MB),"
-	  "statistics=none,statistics_log=(json=0,on_close=0,"
-	  "path=\"WiredTigerStat.%d.%H\",sources=,"
-	  "timestamp=\"%b %d %H:%M:%S\",wait=0),transaction_sync=(enabled=0"
-	  ",method=fsync),use_environment=,use_environment_priv=0,verbose=,"
-	  "version=(major=0,minor=0),write_through=",
+	  "statistics=none,statistics_log=(json=0,on_close=0,path=\".\","
+	  "sources=,timestamp=\"%b %d %H:%M:%S\",wait=0),"
+	  "transaction_sync=(enabled=0,method=fsync),use_environment=,"
+	  "use_environment_priv=0,verbose=,version=(major=0,minor=0),"
+	  "write_through=",
 	  confchk_wiredtiger_open_all, 39
 	},
 	{ "wiredtiger_open_basecfg",
@@ -1224,10 +1239,9 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  "worker_thread_max=4),lsm_merge=,mmap=,multiprocess=0,readonly=0,"
 	  "session_max=100,session_scratch_max=2MB,shared_cache=(chunk=10MB"
 	  ",name=,quota=0,reserve=0,size=500MB),statistics=none,"
-	  "statistics_log=(json=0,on_close=0,path=\"WiredTigerStat.%d.%H\","
-	  "sources=,timestamp=\"%b %d %H:%M:%S\",wait=0),"
-	  "transaction_sync=(enabled=0,method=fsync),verbose=,"
-	  "version=(major=0,minor=0),write_through=",
+	  "statistics_log=(json=0,on_close=0,path=\".\",sources=,"
+	  "timestamp=\"%b %d %H:%M:%S\",wait=0),transaction_sync=(enabled=0"
+	  ",method=fsync),verbose=,version=(major=0,minor=0),write_through=",
 	  confchk_wiredtiger_open_basecfg, 33
 	},
 	{ "wiredtiger_open_usercfg",
@@ -1244,10 +1258,9 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  "worker_thread_max=4),lsm_merge=,mmap=,multiprocess=0,readonly=0,"
 	  "session_max=100,session_scratch_max=2MB,shared_cache=(chunk=10MB"
 	  ",name=,quota=0,reserve=0,size=500MB),statistics=none,"
-	  "statistics_log=(json=0,on_close=0,path=\"WiredTigerStat.%d.%H\","
-	  "sources=,timestamp=\"%b %d %H:%M:%S\",wait=0),"
-	  "transaction_sync=(enabled=0,method=fsync),verbose=,"
-	  "write_through=",
+	  "statistics_log=(json=0,on_close=0,path=\".\",sources=,"
+	  "timestamp=\"%b %d %H:%M:%S\",wait=0),transaction_sync=(enabled=0"
+	  ",method=fsync),verbose=,write_through=",
 	  confchk_wiredtiger_open_usercfg, 32
 	},
 	{ NULL, NULL, NULL, 0 }
diff --git a/src/conn/conn_ckpt.c b/src/conn/conn_ckpt.c
index a23350a5e46..b1d619dc1e8 100644
--- a/src/conn/conn_ckpt.c
+++ b/src/conn/conn_ckpt.c
@@ -23,37 +23,16 @@ __ckpt_server_config(WT_SESSION_IMPL *session, const char **cfg, bool *startp)
 	WT_DECL_RET;
 	char *p;
 
+	*startp = false;
+
 	conn = S2C(session);
 
-	/*
-	 * The checkpoint configuration requires a wait time and/or a log
-	 * size -- if one is not set, we're not running at all.
-	 * Checkpoints based on log size also require logging be enabled.
-	 */
 	WT_RET(__wt_config_gets(session, cfg, "checkpoint.wait", &cval));
 	conn->ckpt_usecs = (uint64_t)cval.val * WT_MILLION;
 
 	WT_RET(__wt_config_gets(session, cfg, "checkpoint.log_size", &cval));
 	conn->ckpt_logsize = (wt_off_t)cval.val;
 
-	/* Checkpoints are incompatible with in-memory configuration */
-	if (conn->ckpt_usecs != 0 || conn->ckpt_logsize != 0) {
-		WT_RET(__wt_config_gets(session, cfg, "in_memory", &cval));
-		if (cval.val != 0)
-			WT_RET_MSG(session, EINVAL,
-			    "In memory configuration incompatible with "
-			    "checkpoints");
-	}
-
-	__wt_log_written_reset(session);
-	if ((conn->ckpt_usecs == 0 && conn->ckpt_logsize == 0) ||
-	    (conn->ckpt_logsize && conn->ckpt_usecs == 0 &&
-	     !FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED))) {
-		*startp = false;
-		return (0);
-	}
-	*startp = true;
-
 	/*
 	 * The application can specify a checkpoint name, which we ignore if
 	 * it's our default.
@@ -72,6 +51,26 @@ __ckpt_server_config(WT_SESSION_IMPL *session, const char **cfg, bool *startp)
 		conn->ckpt_config = p;
 	}
 
+	/*
+	 * The checkpoint configuration requires a wait time and/or a log size,
+	 * if neither is set, we're not running at all. Checkpoints based on log
+	 * size also require logging be enabled.
+	 */
+	if (conn->ckpt_usecs != 0 ||
+	    (conn->ckpt_logsize != 0 &&
+	    FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED))) {
+		/* Checkpoints are incompatible with in-memory configuration */
+		WT_ERR(__wt_config_gets(session, cfg, "in_memory", &cval));
+		if (cval.val != 0)
+			WT_ERR_MSG(session, EINVAL,
+			    "checkpoint configuration incompatible with "
+			    "in-memory configuration");
+
+		__wt_log_written_reset(session);
+
+		*startp = true;
+	}
+
 err:	__wt_scr_free(session, &tmp);
 	return (ret);
 }
@@ -179,7 +178,16 @@ __wt_checkpoint_server_create(WT_SESSION_IMPL *session, const char *cfg[])
 	conn = S2C(session);
 	start = false;
 
-	/* If there is already a server running, shut it down. */
+	/*
+	 * Stop any server that is already running. This means that each time
+	 * reconfigure is called we'll bounce the server even if there are no
+	 * configuration changes. This makes our life easier as the underlying
+	 * configuration routine doesn't have to worry about freeing objects
+	 * in the connection structure (it's guaranteed to always start with a
+	 * blank slate), and we don't have to worry about races where a running
+	 * server is reading configuration information that we're updating, and
+	 * it's not expected that reconfiguration will happen a lot.
+	 */
 	if (conn->ckpt_session != NULL)
 		WT_RET(__wt_checkpoint_server_destroy(session));
 
diff --git a/src/conn/conn_log.c b/src/conn/conn_log.c
index 1ae370ef2fa..18ed71e4688 100644
--- a/src/conn/conn_log.c
+++ b/src/conn/conn_log.c
@@ -51,6 +51,25 @@ __logmgr_config(
 	WT_CONNECTION_IMPL *conn;
 	bool enabled;
 
+	/*
+	 * A note on reconfiguration: the standard "is this configuration string
+	 * allowed" checks should fail if reconfiguration has invalid strings,
+	 * for example, "log=(enabled)", or "statistics_log=(path=XXX)", because
+	 * the connection reconfiguration method doesn't allow those strings.
+	 * Additionally, the base configuration values during reconfiguration
+	 * are the currently configured values (so we don't revert to default
+	 * values when repeatedly reconfiguring), and configuration processing
+	 * of a currently set value should not change the currently set value.
+	 *
+	 * In this code path, log server reconfiguration does not stop/restart
+	 * the log server, so there's no point in re-evaluating configuration
+	 * strings that cannot be reconfigured, risking bugs in configuration
+	 * setup, and depending on evaluation of currently set values to always
+	 * result in the currently set value. Skip tests for any configuration
+	 * strings which don't make sense during reconfiguration, but don't
+	 * worry about error reporting because it should never happen.
+	 */
+
 	conn = S2C(session);
 
 	WT_RET(__wt_config_gets(session, cfg, "log.enabled", &cval));
@@ -62,6 +81,8 @@ __logmgr_config(
 	 *
 	 * If it is off and the user it turning it on, or it is on
 	 * and the user is turning it off, return an error.
+	 *
+	 * See above: should never happen.
 	 */
 	if (reconfig &&
 	    ((enabled && !FLD_ISSET(conn->log_flags, WT_CONN_LOG_ENABLED)) ||
@@ -83,6 +104,8 @@ __logmgr_config(
 	 * Setup a log path and compression even if logging is disabled in case
 	 * we are going to print a log.  Only do this on creation.  Once a
 	 * compressor or log path are set they cannot be changed.
+	 *
+	 * See above: should never happen.
 	 */
 	if (!reconfig) {
 		conn->log_compressor = NULL;
@@ -95,6 +118,7 @@ __logmgr_config(
 		WT_RET(__wt_strndup(
 		    session, cval.str, cval.len, &conn->log_path));
 	}
+
 	/* We are done if logging isn't enabled. */
 	if (!*runp)
 		return (0);
@@ -103,13 +127,14 @@ __logmgr_config(
 	if (cval.val != 0)
 		FLD_SET(conn->log_flags, WT_CONN_LOG_ARCHIVE);
 
+	/*
+	 * The file size cannot be reconfigured. The amount of memory allocated
+	 * to the log slots may be based on the log file size at creation and we
+	 * don't want to re-allocate that memory while running.
+	 *
+	 * See above: should never happen.
+	 */
 	if (!reconfig) {
-		/*
-		 * Ignore if the user tries to change the file size.  The
-		 * amount of memory allocated to the log slots may be based
-		 * on the log file size at creation and we don't want to
-		 * re-allocate that memory while running.
-		 */
 		WT_RET(__wt_config_gets(session, cfg, "log.file_max", &cval));
 		conn->log_file_max = (wt_off_t)cval.val;
 		WT_STAT_FAST_CONN_SET(session,
@@ -125,12 +150,17 @@ __logmgr_config(
 		conn->log_prealloc = 1;
 
 	/*
-	 * Note that it is meaningless to reconfigure this value during
-	 * runtime.  It only matters on create before recovery runs.
+	 * Note it's meaningless to reconfigure this value during runtime, it
+	 * only matters on create before recovery runs.
+	 *
+	 * See above: should never happen.
 	 */
-	WT_RET(__wt_config_gets_def(session, cfg, "log.recover", 0, &cval));
-	if (cval.len != 0  && WT_STRING_MATCH("error", cval.str, cval.len))
-		FLD_SET(conn->log_flags, WT_CONN_LOG_RECOVER_ERR);
+	if (!reconfig) {
+		WT_RET(__wt_config_gets_def(
+		    session, cfg, "log.recover", 0, &cval));
+		if (WT_STRING_MATCH("error", cval.str, cval.len))
+			FLD_SET(conn->log_flags, WT_CONN_LOG_RECOVER_ERR);
+	}
 
 	WT_RET(__wt_config_gets(session, cfg, "log.zero_fill", &cval));
 	if (cval.val != 0) {
diff --git a/src/conn/conn_stat.c b/src/conn/conn_stat.c
index 855ff57808e..5ca0f1855d9 100644
--- a/src/conn/conn_stat.c
+++ b/src/conn/conn_stat.c
@@ -73,20 +73,37 @@ __statlog_config(WT_SESSION_IMPL *session, const char **cfg, bool *runp)
 	WT_CONFIG objectconf;
 	WT_CONFIG_ITEM cval, k, v;
 	WT_CONNECTION_IMPL *conn;
+	WT_DECL_ITEM(tmp);
 	WT_DECL_RET;
 	int cnt;
 	char **sources;
 
+	/*
+	 * A note on reconfiguration: the standard "is this configuration string
+	 * allowed" checks should fail if reconfiguration has invalid strings,
+	 * for example, "log=(enabled)", or "statistics_log=(path=XXX)", because
+	 * the connection reconfiguration method doesn't allow those strings.
+	 * Additionally, the base configuration values during reconfiguration
+	 * are the currently configured values (so we don't revert to default
+	 * values when repeatedly reconfiguring), and configuration processing
+	 * of a currently set value should not change the currently set value.
+	 *
+	 * In this code path, a previous statistics log server reconfiguration
+	 * may have stopped the server (and we're about to restart it). Because
+	 * stopping the server discarded the configured information stored in
+	 * the connection structure, we have to re-evaluate all configuration
+	 * values, reconfiguration can't skip any of them.
+	 */
+
 	conn = S2C(session);
 	sources = NULL;
 
-	WT_RET(__wt_config_gets(session, cfg, "statistics_log.wait", &cval));
 	/* Only start the server if wait time is non-zero */
+	WT_RET(__wt_config_gets(session, cfg, "statistics_log.wait", &cval));
 	*runp = cval.val != 0;
 	conn->stat_usecs = (uint64_t)cval.val * WT_MILLION;
 
-	WT_RET(__wt_config_gets(
-	    session, cfg, "statistics_log.json", &cval));
+	WT_RET(__wt_config_gets(session, cfg, "statistics_log.json", &cval));
 	if (cval.val != 0)
 		FLD_SET(conn->stat_flags, WT_CONN_STAT_JSON);
 
@@ -96,24 +113,30 @@ __statlog_config(WT_SESSION_IMPL *session, const char **cfg, bool *runp)
 		FLD_SET(conn->stat_flags, WT_CONN_STAT_ON_CLOSE);
 
 	/*
-	 * Statistics logging configuration requires either a wait time or an
-	 * on-close setting.
-	 */
-	if (!*runp && !FLD_ISSET(conn->stat_flags, WT_CONN_STAT_ON_CLOSE))
-		return (0);
-
-	/*
-	 * If any statistics logging is done, this must not be a read-only
-	 * connection.
+	 * We don't allow the log path to be reconfigured for security reasons.
+	 * (Applications passing input strings directly to reconfigure would
+	 * expose themselves to a potential security problem, the utility of
+	 * reconfiguring a statistics log path isn't worth the security risk.)
+	 *
+	 * See above for the details, but during reconfiguration we're loading
+	 * the path value from the saved configuration information, and it's
+	 * required during reconfiguration because we potentially stopped and
+	 * are restarting, the server.
 	 */
-	WT_RET(__wt_config_gets(session, cfg, "statistics_log.sources", &cval));
-	WT_RET(__wt_config_subinit(session, &objectconf, &cval));
+	WT_RET(__wt_config_gets(session, cfg, "statistics_log.path", &cval));
+	WT_ERR(__wt_scr_alloc(session, 0, &tmp));
+	WT_ERR(__wt_buf_fmt(session,
+	    tmp, "%.*s/%s", (int)cval.len, cval.str, WT_STATLOG_FILENAME));
+	WT_ERR(__wt_filename(session, tmp->data, &conn->stat_path));
+
+	WT_ERR(__wt_config_gets(session, cfg, "statistics_log.sources", &cval));
+	WT_ERR(__wt_config_subinit(session, &objectconf, &cval));
 	for (cnt = 0; (ret = __wt_config_next(&objectconf, &k, &v)) == 0; ++cnt)
 		;
-	WT_RET_NOTFOUND_OK(ret);
+	WT_ERR_NOTFOUND_OK(ret);
 	if (cnt != 0) {
-		WT_RET(__wt_calloc_def(session, cnt + 1, &sources));
-		WT_RET(__wt_config_subinit(session, &objectconf, &cval));
+		WT_ERR(__wt_calloc_def(session, cnt + 1, &sources));
+		WT_ERR(__wt_config_subinit(session, &objectconf, &cval));
 		for (cnt = 0;
 		    (ret = __wt_config_next(&objectconf, &k, &v)) == 0; ++cnt) {
 			/*
@@ -138,29 +161,34 @@ __statlog_config(WT_SESSION_IMPL *session, const char **cfg, bool *runp)
 		sources = NULL;
 	}
 
-	WT_ERR(__wt_config_gets(session, cfg, "statistics_log.path", &cval));
-	WT_ERR(__wt_nfilename(session, cval.str, cval.len, &conn->stat_path));
-
 	/*
 	 * When using JSON format, use the same timestamp format as MongoDB by
-	 * default.
+	 * default. This requires caution: the user might have set the timestamp
+	 * in a previous reconfigure call and we don't want to override that, so
+	 * compare the retrieved value with the default value to decide if we
+	 * should use the JSON default.
+	 *
+	 * (This still implies if the user explicitly sets the timestamp to the
+	 * default value, then sets the JSON flag in a separate reconfigure
+	 * call, or vice-versa, we will incorrectly switch to the JSON default
+	 * timestamp. But there's no way to detect that, and this is all a low
+	 * probability path.)
 	 */
-	if (FLD_ISSET(conn->stat_flags, WT_CONN_STAT_JSON)) {
-		ret = __wt_config_gets(
-		    session, &cfg[1], "statistics_log.timestamp", &cval);
-		if (ret == WT_NOTFOUND)
-			WT_ERR(__wt_strdup(
-			    session, "%FT%T.000Z", &conn->stat_format));
-		WT_ERR_NOTFOUND_OK(ret);
-	}
-	if (conn->stat_format == NULL) {
-		WT_ERR(__wt_config_gets(
-		    session, cfg, "statistics_log.timestamp", &cval));
+#define	WT_TIMESTAMP_DEFAULT		"%b %d %H:%M:%S"
+#define	WT_TIMESTAMP_JSON_DEFAULT	"%FT%T.000Z"
+	WT_ERR(__wt_config_gets(
+	    session, cfg, "statistics_log.timestamp", &cval));
+	if (FLD_ISSET(conn->stat_flags, WT_CONN_STAT_JSON) &&
+	    WT_STRING_MATCH(WT_TIMESTAMP_DEFAULT, cval.str, cval.len))
+		WT_ERR(__wt_strdup(
+		    session, WT_TIMESTAMP_JSON_DEFAULT, &conn->stat_format));
+	else
 		WT_ERR(__wt_strndup(
 		    session, cval.str, cval.len, &conn->stat_format));
-	}
 
 err:	__stat_sources_free(session, &sources);
+	__wt_scr_free(session, &tmp);
+
 	return (ret);
 }
 
@@ -538,12 +566,16 @@ __wt_statlog_create(WT_SESSION_IMPL *session, const char *cfg[])
 	bool start;
 
 	conn = S2C(session);
-	start = false;
 
 	/*
 	 * Stop any server that is already running. This means that each time
 	 * reconfigure is called we'll bounce the server even if there are no
-	 * configuration changes - but that makes our lives easier.
+	 * configuration changes. This makes our life easier as the underlying
+	 * configuration routine doesn't have to worry about freeing objects
+	 * in the connection structure (it's guaranteed to always start with a
+	 * blank slate), and we don't have to worry about races where a running
+	 * server is reading configuration information that we're updating, and
+	 * it's not expected that reconfiguration will happen a lot.
 	 */
 	if (conn->stat_session != NULL)
 		WT_RET(__wt_statlog_destroy(session, false));
diff --git a/src/docs/security.dox b/src/docs/security.dox
index 331f74d969b..82e13ae7ad3 100644
--- a/src/docs/security.dox
+++ b/src/docs/security.dox
@@ -2,10 +2,23 @@
 
 @section directory_permissions Database directory permissions
 
-All WiredTiger files are stored in the database home directory, and the
-WiredTiger database directory should have its permissions set to ensure
-database objects are not accessible to users without appropriate
-permissions.  See @ref home for more information.
+By default, WiredTiger files are stored beneath the database home directory.
+The WiredTiger database directory should have its permissions set to ensure
+database objects are not accessible to users without appropriate permissions.
+See @ref home for more information.
+
+@section absolute_path Absolute paths
+
+WiredTiger prepends the name of the database home to file names which
+do not appear to be absolute paths. (The absolute path test is
+simplistic, matching a leading slash character on POSIX systems or a
+leading alphabetic character and colon on Windows.) No file path
+sanitization or validation is done by WiredTiger, for example, file
+paths may match universal naming conventions (UNC), or include \c "../"
+(dot dot slash) components.
+
+Applications are responsible for validating user-supplied file paths as
+necessary to prevent directory traversal attacks.
 
 @section file_permissions File permissions
 
diff --git a/src/docs/spell.ok b/src/docs/spell.ok
index 96fe04d7426..e08eb7d1447 100644
--- a/src/docs/spell.ok
+++ b/src/docs/spell.ok
@@ -80,6 +80,7 @@ SCons
 Seward's
 SiH
 TXT
+UNC
 URIs
 WILLNEED
 WiredTiger
@@ -368,6 +369,7 @@ php
 png
 posix
 pre
+prepends
 primary's
 printf
 printlog
@@ -411,6 +413,7 @@ runtime
 rwlock
 sHQ
 sHq
+sanitization
 scalable
 scanf
 schemas
diff --git a/src/docs/statistics.dox b/src/docs/statistics.dox
index 0a29e351e4e..36ce2711dc5 100644
--- a/src/docs/statistics.dox
+++ b/src/docs/statistics.dox
@@ -90,11 +90,20 @@ cursor.
 
 @section statistics_log Statistics logging
 
-WiredTiger will optionally log database statistics into a file when the
+WiredTiger will optionally log database statistics into files when the
 the ::wiredtiger_open \c statistics_log configuration is set.
 
-The resulting statistics can be displayed using the \c wtstats visualization
-tool.  For more information, see @ref_single wtstats.
+The log files are named \c WiredTiger.%%d.%%H, where \c %%d is replaced
+with the day of the month as a decimal number (01-31), and \c %%H
+is replaced by the hour (24-hour clock) as a decimal number (00-23).
+Each log file contains the statistics for the hour specified in its name.
+
+The location of the log files may be changed with the \c statistics_log.path
+configuration string.
+
+The resulting statistics can be displayed and interactively examined
+using the \c wtstats visualization tool.  For more information, see
+@ref_single wtstats.
 
 The following example logs statistics every 30 seconds:
 
@@ -120,7 +129,7 @@ Statistics for all underlying data sources of a particular type may be
 included by adding a partial data source URI to the \c statistics_log
 configuration string:
 
-@snippet ex_all.c Statistics logging with all tables
+@snippet ex_all.c Statistics logging with a source type
 
 When database statistics are logged, the database home will be the first
 space-separated entry for each record in the log file.  For example:
@@ -151,23 +160,9 @@ currently open in the database, nor will any statistics requiring the
 traversal of a tree (as if the \c statistics_fast configuration string
 were set).
 
-The location of the log files may be changed with the \c statistics_log.path
-configuration string.  The \c path value value may contain ISO C90 standard
-strftime conversion specifications.  WiredTiger will not create non-existent
-directories in the path, they must exist before ::wiredtiger_open is called.
-
-The following example logs statistics into files named with the month,
-day and year:
-
-@snippet ex_all.c Statistics logging with path
-
 A Python script that parses the default logging output and uses the
 <a href="http://www.gnuplot.info/">gnuplot</a>, utility to generate
 Portable Network Graphics (PNG) format graphs is included in the
 WiredTiger distribution in the file \c tools/statlog.py.
 
-@m_if{c}
-To interactively examine statistics results, see @ref wtstats.
-@m_endif
-
 */
diff --git a/src/docs/upgrading.dox b/src/docs/upgrading.dox
index 5e824fee977..c5fbc0a86a2 100644
--- a/src/docs/upgrading.dox
+++ b/src/docs/upgrading.dox
@@ -1,5 +1,16 @@
 /*! @page upgrading Upgrading WiredTiger applications
 
+@section version_281 Upgrading to Version 2.8.1
+<dl>
+<dt>Statistics logging path</dt>
+<dd>
+The statistics logging path configuration has been simplified to be only a
+path to a directory, and the file name component of the path may no longer
+be specified. Applications depending on the ability to set statistics log
+file names will require modifications.
+</dd>
+
+</dl><hr>
 @section version_280 Upgrading to Version 2.8.0
 <dl>
 <dt>LSM metadata</dt>
@@ -55,7 +66,6 @@ The WiredTiger public API used to define a structure that could encapsulate
 log sequence numbers. That structure is no longer exposed publicly.
 </dd>
 
-<dt>
 </dl><hr>
 @section version_270 Upgrading to Version 2.7.0
 
diff --git a/src/include/connection.h b/src/include/connection.h
index 0e0c357279a..804498f6869 100644
--- a/src/include/connection.h
+++ b/src/include/connection.h
@@ -314,6 +314,7 @@ struct __wt_connection_impl {
 	uint32_t	 evict_workers;	/* Number of eviction workers */
 	WT_EVICT_WORKER	*evict_workctx;	/* Eviction worker context */
 
+#define	WT_STATLOG_FILENAME	"WiredTigerStat.%d.%H"
 	WT_SESSION_IMPL *stat_session;	/* Statistics log session */
 	wt_thread_t	 stat_tid;	/* Statistics log thread */
 	bool		 stat_tid_set;	/* Statistics log thread set */
diff --git a/src/include/wiredtiger.in b/src/include/wiredtiger.in
index f578f4e6c08..daefe09044c 100644
--- a/src/include/wiredtiger.in
+++ b/src/include/wiredtiger.in
@@ -1836,25 +1836,8 @@ struct __wt_connection {
 	 * configuration options defined below.}
 	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;archive, automatically archive
 	 * unneeded log files., a boolean flag; default \c true.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;compressor, configure a compressor
-	 * for log records.  Permitted values are \c "none" or custom
-	 * compression engine name created with WT_CONNECTION::add_compressor.
-	 * If WiredTiger has builtin support for \c "snappy"\, \c "lz4" or \c
-	 * "zlib" compression\, these names are also available.  See @ref
-	 * compression for more information., a string; default \c none.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;enabled, enable logging subsystem., a
-	 * boolean flag; default \c false.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;file_max, the maximum size of log
-	 * files., an integer between 100KB and 2GB; default \c 100MB.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the path to a directory into
-	 * which the log files are written.  If the value is not an absolute
-	 * path name\, the files are created relative to the database home., a
-	 * string; default \c ".".}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;prealloc,
-	 * pre-allocate log files., a boolean flag; default \c true.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;recover, run recovery or error if
-	 * recovery needs to run after an unclean shutdown., a string\, chosen
-	 * from the following options: \c "error"\, \c "on"; default \c on.}
+	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;prealloc, pre-allocate log files., a
+	 * boolean flag; default \c true.}
 	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;zero_fill, manually write zeroes into
 	 * log files., a boolean flag; default \c false.}
 	 * @config{ ),,}
@@ -1914,11 +1897,6 @@ struct __wt_connection {
 	 * statistics in JSON format., a boolean flag; default \c false.}
 	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;on_close, log statistics on database
 	 * close., a boolean flag; default \c false.}
-	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the pathname to a file into
-	 * which the log records are written\, may contain ISO C standard
-	 * strftime conversion specifications.  If the value is not an absolute
-	 * path name\, the file is created relative to the database home., a
-	 * string; default \c "WiredTigerStat.%d.%H".}
 	 * @config{&nbsp;&nbsp;&nbsp;&nbsp;sources, if non-empty\, include
 	 * statistics for the list of data source URIs\, if they are open at the
 	 * time of the statistics logging.  The list may include URIs matching a
@@ -2343,9 +2321,10 @@ struct __wt_connection {
  * subsystem., a boolean flag; default \c false.}
  * @config{&nbsp;&nbsp;&nbsp;&nbsp;file_max, the maximum size of log files., an
  * integer between 100KB and 2GB; default \c 100MB.}
- * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the path to a directory into which the
- * log files are written.  If the value is not an absolute path name\, the files
- * are created relative to the database home., a string; default \c ".".}
+ * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the name of a directory into which log
+ * files are written.  The directory must already exist.  If the value is not an
+ * absolute path\, the path is relative to the database home (see @ref
+ * absolute_path for more information)., a string; default \c ".".}
  * @config{&nbsp;&nbsp;&nbsp;&nbsp;prealloc, pre-allocate log files., a boolean
  * flag; default \c true.}
  * @config{&nbsp;&nbsp;&nbsp;&nbsp;recover, run recovery
@@ -2415,16 +2394,15 @@ struct __wt_connection {
  * boolean flag; default \c false.}
  * @config{&nbsp;&nbsp;&nbsp;&nbsp;on_close,
  * log statistics on database close., a boolean flag; default \c false.}
- * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the pathname to a file into which the
- * log records are written\, may contain ISO C standard strftime conversion
- * specifications.  If the value is not an absolute path name\, the file is
- * created relative to the database home., a string; default \c
- * "WiredTigerStat.%d.%H".}
- * @config{&nbsp;&nbsp;&nbsp;&nbsp;sources, if
- * non-empty\, include statistics for the list of data source URIs\, if they are
- * open at the time of the statistics logging.  The list may include URIs
- * matching a single data source ("table:mytable")\, or a URI matching all data
- * sources of a particular type ("table:")., a list of strings; default empty.}
+ * @config{&nbsp;&nbsp;&nbsp;&nbsp;path, the name of a directory into which
+ * statistics files are written.  The directory must already exist.  If the
+ * value is not an absolute path\, the path is relative to the database home
+ * (see @ref absolute_path for more information)., a string; default \c ".".}
+ * @config{&nbsp;&nbsp;&nbsp;&nbsp;sources, if non-empty\, include statistics
+ * for the list of data source URIs\, if they are open at the time of the
+ * statistics logging.  The list may include URIs matching a single data source
+ * ("table:mytable")\, or a URI matching all data sources of a particular type
+ * ("table:")., a list of strings; default empty.}
  * @config{&nbsp;&nbsp;&nbsp;&nbsp;timestamp, a timestamp prepended to each log
  * record\, may contain strftime conversion specifications\, when \c json is
  * configured\, defaults to \c "%FT%Y.000Z"., a string; default \c "%b %d
diff --git a/src/os_win/os_path.c b/src/os_win/os_path.c
index 220752ce7a1..74050600417 100644
--- a/src/os_win/os_path.c
+++ b/src/os_win/os_path.c
@@ -16,8 +16,30 @@ bool
 __wt_absolute_path(const char *path)
 {
 	/*
-	 * Check for a drive name (for example, "D:"), allow both forward and
-	 * backward slashes.
+	 * https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247
+	 *
+	 * For Windows API functions that manipulate files, file names can often
+	 * be relative to the current directory, while some APIs require a fully
+	 * qualified path. A file name is relative to the current directory if
+	 * it does not begin with one of the following:
+	 *
+	 * -- A UNC name of any format, which always start with two backslash
+	 *    characters ("\\").
+	 * -- A disk designator with a backslash, for example "C:\" or "d:\".
+	 * -- A single backslash, for example, "\directory" or "\file.txt". This
+	 *    is also referred to as an absolute path.
+	 *
+	 * If a file name begins with only a disk designator but not the
+	 * backslash after the colon, it is interpreted as a relative path to
+	 * the current directory on the drive with the specified letter. Note
+	 * that the current directory may or may not be the root directory
+	 * depending on what it was set to during the most recent "change
+	 * directory" operation on that disk.
+	 *
+	 * -- "C:tmp.txt" refers to a file named "tmp.txt" in the current
+	 *    directory on drive C.
+	 * -- "C:tempdir\tmp.txt" refers to a file in a subdirectory to the
+	 *    current directory on drive C.
 	 */
 	if (strlen(path) >= 3 && __wt_isalpha(path[0]) && path[1] == ':')
 		path += 2;
diff --git a/test/suite/test_reconfig01.py b/test/suite/test_reconfig01.py
index 876de1fe5af..419ff876dc2 100644
--- a/test/suite/test_reconfig01.py
+++ b/test/suite/test_reconfig01.py
@@ -95,19 +95,24 @@ class test_reconfig01(wttest.WiredTigerTestCase):
         self.conn.reconfigure("checkpoint=(wait=0,name=hi)")
         self.conn.reconfigure("checkpoint=(wait=5,name=hi)")
 
-    def test_reconfig_stat_log(self):
+    # Statistics logging: reconfigure the things we can reconfigure.
+    def test_reconfig_statistics_log_ok(self):
         self.conn.reconfigure("statistics=[all],statistics_log=(wait=0)")
         self.conn.reconfigure("statistics_log=(wait=0)")
-        self.conn.reconfigure("statistics_log=(wait=2)")
+        self.conn.reconfigure("statistics_log=(wait=2,json=true)")
+        self.conn.reconfigure("statistics_log=(wait=0)")
+        self.conn.reconfigure("statistics_log=(wait=2,on_close=true)")
         self.conn.reconfigure("statistics_log=(wait=0)")
         self.conn.reconfigure("statistics_log=(wait=2,sources=[lsm:])")
         self.conn.reconfigure("statistics_log=(wait=0)")
         self.conn.reconfigure("statistics_log=(wait=2,timestamp=\"t%b %d\")")
         self.conn.reconfigure("statistics_log=(wait=0)")
-        self.conn.reconfigure("statistics_log=(wait=2,path=\"wts.%d.%H\")")
-        self.conn.reconfigure("statistics_log=(wait=0)")
-        self.conn.reconfigure(
-             "statistics_log=(wait=2,sources=[lsm:],timestamp=\"%b\")")
+
+    # Statistics logging: reconfigure the things we can't reconfigure.
+    def test_reconfig_statistics_log_fail(self):
+        msg = '/unknown configuration key/'
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(path=foo)"), msg)
 
     def test_file_manager(self):
         self.conn.reconfigure("file_manager=(close_scan_interval=3)")
diff --git a/test/suite/test_reconfig02.py b/test/suite/test_reconfig02.py
index 85a9ceb2a34..9d9ac220aa7 100644
--- a/test/suite/test_reconfig02.py
+++ b/test/suite/test_reconfig02.py
@@ -41,24 +41,29 @@ class test_reconfig02(wttest.WiredTigerTestCase):
         self.conn_config = self.init_config
         return wttest.WiredTigerTestCase.setUpConnectionOpen(self, dir)
 
-    # Call reconfigure for zero filling a file.  There is nothing
-    # we can actually look for to confirm it did anything.
-    # Also changing the log file size is a no-op, but should not fail.
+    # Logging: reconfigure the things we can reconfigure.
     def test_reconfig02_simple(self):
+        self.conn.reconfigure("log=(archive=false)")
+        self.conn.reconfigure("log=(prealloc=false)")
+        self.conn.reconfigure("log=(zero_fill=false)")
+
+        self.conn.reconfigure("log=(archive=true)")
+        self.conn.reconfigure("log=(prealloc=true)")
         self.conn.reconfigure("log=(zero_fill=true)")
-        self.conn.reconfigure("log=(file_max=1MB)")
 
-    # Test that we get an error if we try to turn logging off.
+    # Logging: reconfigure the things we can't reconfigure.
     def test_reconfig02_disable(self):
-        msg = 'Invalid argument'
-        gotException = False
-        try:
-            self.conn.reconfigure("log=(enabled=false)")
-        except wiredtiger.WiredTigerError as e:
-            gotException = True
-            self.pr('got exception: ' + str(e))
-            self.assertTrue(str(e).find(msg) >= 0)
-        self.assertTrue(gotException)
+        msg = '/unknown configuration key/'
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(enabled=true)"), msg)
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(compressor=foo)"), msg)
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(file_max=1MB)"), msg)
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(path=foo)"), msg)
+        self.assertRaisesWithMessage(wiredtiger.WiredTigerError,
+            lambda: self.conn.reconfigure("log=(recovery=true)"), msg)
 
     # Logging starts on, but prealloc is off.  Verify it is off.
     # Reconfigure it on and run again, making sure that log files
diff --git a/test/suite/test_stat_log01.py b/test/suite/test_stat_log01.py
index f6033d940c5..65ce80dfe7d 100644
--- a/test/suite/test_stat_log01.py
+++ b/test/suite/test_stat_log01.py
@@ -51,9 +51,10 @@ class test_stat_log01(wttest.WiredTigerTestCase):
             None, "create,statistics=(fast),statistics_log=(wait=1)")
         # Wait for the default interval, to ensure stats have been written.
         time.sleep(2)
-        self.check_stats_file("WiredTigerStat")
+        self.check_stats_file(".")
 
     def test_stats_log_name(self):
+        os.mkdir("foo")
         self.conn = self.wiredtiger_open(
             None, "create,statistics=(fast),statistics_log=(wait=1,path=foo)")
         # Wait for the default interval, to ensure stats have been written.
@@ -66,21 +67,18 @@ class test_stat_log01(wttest.WiredTigerTestCase):
         # Wait for the default interval, to ensure stats have been written.
         time.sleep(2)
         self.close_conn()
-        self.check_stats_file("WiredTigerStat")
+        self.check_stats_file(".")
 
     def test_stats_log_on_close(self):
         self.conn = self.wiredtiger_open(None,
             "create,statistics=(fast),statistics_log=(on_close=true)")
         # Close the connection to ensure the statistics get generated.
         self.close_conn()
-        self.check_stats_file("WiredTigerStat")
+        self.check_stats_file(".")
 
-    def check_stats_file(self, filename):
-        if filename == "WiredTigerStat":
-            files = glob.glob(filename + '.[0-9]*')
-            self.assertTrue(files)
-        else:
-            self.assertTrue(os.path.isfile(filename))
+    def check_stats_file(self, dir):
+        files = glob.glob(dir + '/' + 'WiredTigerStat.[0-9]*')
+        self.assertTrue(files)
 
 if __name__ == '__main__':
     wttest.run()