Merge branch 'develop' into mongodb-3.4

47 files changed, 634 insertions, 367 deletions

diff --git a/.gitignore b/.gitignore
index bef47daabf9..cd1873533ca 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,11 +16,12 @@
 *.obj
 *.pdb
 *.pyc
+.dirstamp
 .sconf_temp
 .sconsign.dblite
-.dirstamp
 /Makefile.am
 /aclocal.m4
+/autom4te.cache/
 /build_posix/aclocal/libtool.m4
 /build_posix/aclocal/ltoptions.m4
 /build_posix/aclocal/ltsugar.m4
@@ -32,7 +33,7 @@
 /config.status
 /configure
 /configure.ac
-/libtool/
+/libtool
 /stamp-h1
 /wiredtiger.h
 /wiredtiger.pc
@@ -63,9 +64,9 @@ WT_TEST/
 
 # Python
 /lang/python/_wiredtiger.so
+/lang/python/wiredtiger.py
 /lang/python/wiredtiger/__init__.py
 /lang/python/wiredtiger/_wiredtiger.pyd
-/lang/python/wiredtiger.py
 /lang/python/wiredtiger_wrap.c
 _wiredtiger.pyd
 
@@ -106,6 +107,7 @@ _wiredtiger.pyd
 **/test/csuite/test_wt2719_reconfig
 **/test/csuite/test_wt2834_join_bloom_fix
 **/test/csuite/test_wt2853_perf
+**/test/csuite/test_wt2999_join_extractor
 **/test/cursor_order/cursor_order
 **/test/fops/t
 **/test/format/s_dumpcmp
diff --git a/dist/api_data.py b/dist/api_data.py
index 22d06c380ae..5a81e8dd080 100644
--- a/dist/api_data.py
+++ b/dist/api_data.py
@@ -190,9 +190,8 @@ file_config = format_meta + [
         WiredTiger to consume memory over the configured cache limit''',
         type='boolean'),
     Config('internal_key_truncate', 'true', r'''
-        configure internal key truncation, discarding unnecessary
-        trailing bytes on internal keys (ignored for custom
-        collators)''',
+        configure internal key truncation, discarding unnecessary trailing
+        bytes on internal keys (ignored for custom collators)''',
         type='boolean'),
     Config('internal_page_max', '4KB', r'''
         the maximum page size for internal nodes, in bytes; the size
@@ -637,6 +636,12 @@ wiredtiger_open_statistics_log_configuration = [
 ]
 
 session_config = [
+    Config('ignore_cache_size', 'false', r'''
+        when set, operations performed by this session ignore the cache size
+        and are not blocked when the cache is full.  Note that use of this
+        option for operations that create cache pressure can starve ordinary
+        sessions that obey the cache size.''',
+        type='boolean'),
     Config('isolation', 'read-committed', r'''
         the default isolation level for operations in this session''',
         choices=['read-uncommitted', 'read-committed', 'snapshot']),
@@ -652,6 +657,11 @@ wiredtiger_open_common =\
         should be used (4KB on Linux systems when direct I/O is configured,
         zero elsewhere)''',
         min='-1', max='1MB'),
+    Config('builtin_extension_config', '', r'''
+        A structure where the keys are the names of builtin extensions and the
+        values are passed to WT_CONNECTION::load_extension as the \c config
+        parameter (for example,
+        <code>builtin_extension_config={zlib={compression_level=3}}</code>)'''),
     Config('checkpoint_sync', 'true', r'''
         flush files to stable storage when closing or writing
         checkpoints''',
diff --git a/dist/s_all b/dist/s_all
index 31abab28910..4c9d4eccebb 100755
--- a/dist/s_all
+++ b/dist/s_all
@@ -84,22 +84,23 @@ run "sh ./s_copyright"
 run "sh ./s_style"
 
 COMMANDS="
-2>&1 ./s_tags > ${t_pfx}tags
 2>&1 ./s_define > ${t_pfx}s_define
-2>&1 ./s_typedef -c > ${t_pfx}s_typedef_c
-2>&1 ./s_funcs > ${t_pfx}s_funcs
+2>&1 ./s_docs > ${t_pfx}s_docs
 2>&1 ./s_export > ${t_pfx}s_export
+2>&1 ./s_funcs > ${t_pfx}s_funcs
 2>&1 ./s_getopt > ${t_pfx}s_getopt
 2>&1 ./s_label > ${t_pfx}s_label
 2>&1 ./s_lang > ${t_pfx}s_lang
 2>&1 ./s_longlines > ${t_pfx}s_longlines
+2>&1 ./s_python > ${t_pfx}s_python
 2>&1 ./s_stat > ${t_pfx}_stat
 2>&1 ./s_string > ${t_pfx}s_string
-2>&1 python style.py > ${t_pfx}py_style
-2>&1 ./s_python > ${t_pfx}s_python
+2>&1 ./s_tags > ${t_pfx}tags
+2>&1 ./s_typedef -c > ${t_pfx}s_typedef_c
+2>&1 ./s_void > ${t_pfx}s_void"
 2>&1 ./s_whitespace > ${t_pfx}s_whitespace
 2>&1 ./s_win > ${t_pfx}s_win
-2>&1 ./s_docs > ${t_pfx}s_docs"
+2>&1 python style.py > ${t_pfx}py_style
 
 # Parallelize if possible.
 xp=""
diff --git a/dist/s_string.ok b/dist/s_string.ok
index 65c74b61995..d19c05e802b 100644
--- a/dist/s_string.ok
+++ b/dist/s_string.ok
@@ -863,6 +863,7 @@ lu
 lwsync
 lz
 lzo
+mT
 madvise
 majorp
 malloc
diff --git a/dist/s_void b/dist/s_void
index b9c3f5e0ef7..16684e962e6 100644..100755
--- a/dist/s_void
+++ b/dist/s_void
@@ -134,8 +134,12 @@ for f in `find bench ext src test -name '*.[ci]'`; do
 	    -e 's/^ *//' |
 	func_ok > $t
 	test -s $t && {
-		echo "========== $f"
-		cat $t
+		echo "=============================================="
+		echo "$f:"
+		cat $t | sed 's/^/	/'
+		echo "Function could return void instead of int."
+		echo "Add false positives to the list in dist/s_void."
+		echo "=============================================="
 	}
 done
 
diff --git a/examples/c/ex_file_system.c b/examples/c/ex_file_system.c
index 524a5d03f89..f51cad328c3 100644
--- a/examples/c/ex_file_system.c
+++ b/examples/c/ex_file_system.c
@@ -194,19 +194,9 @@ demo_file_system_create(WT_CONNECTION *conn, WT_CONFIG_ARG *config)
 	 * the underlying filesystem implementation. See the main function for
 	 * the setup of those configuration strings; here we parse configuration
 	 * information as passed in by main, through WiredTiger.
-	 *
-	 * Retrieve our configuration information, the "config" value.
 	 */
-	if ((ret = wtext->config_get(wtext, NULL, config, "config", &v)) != 0) {
-		(void)wtext->err_printf(wtext, NULL,
-		    "WT_EXTENSION_API.config_get: config: %s",
-		    wtext->strerror(wtext, NULL, ret));
-		goto err;
-	}
-
-	/* Open a WiredTiger parser on the "config" value. */
-	if ((ret = wtext->config_parser_open(
-	    wtext, NULL, v.str, v.len, &config_parser)) != 0) {
+	if ((ret = wtext->config_parser_open_arg(
+	    wtext, NULL, config, &config_parser)) != 0) {
 		(void)wtext->err_printf(wtext, NULL,
 		    "WT_EXTENSION_API.config_parser_open: config: %s",
 		    wtext->strerror(wtext, NULL, ret));
diff --git a/ext/compressors/zlib/zlib_compress.c b/ext/compressors/zlib/zlib_compress.c
index 3665ec48b9a..09a793646e7 100644
--- a/ext/compressors/zlib/zlib_compress.c
+++ b/ext/compressors/zlib/zlib_compress.c
@@ -483,8 +483,7 @@ static int
 zlib_init_config(
     WT_CONNECTION *connection, WT_CONFIG_ARG *config, int *zlib_levelp)
 {
-	WT_CONFIG_ITEM k, v;
-	WT_CONFIG_PARSER *config_parser;
+	WT_CONFIG_ITEM v;
 	WT_EXTENSION_API *wt_api;
 	int ret, zlib_level;
 
@@ -497,49 +496,27 @@ zlib_init_config(
 	 * level; review the configuration.
 	 */
 	wt_api = connection->get_extension_api(connection);
-	if ((ret =
-	    wt_api->config_get(wt_api, NULL, config, "config", &v)) != 0) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_EXTENSION_API.config_get: zlib configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	if ((ret = wt_api->config_parser_open(
-	    wt_api, NULL, v.str, v.len, &config_parser)) != 0) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_EXTENSION_API.config_parser_open: zlib configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	while ((ret = config_parser->next(config_parser, &k, &v)) == 0)
-		if (strlen("compression_level") == k.len &&
-		    strncmp("compression_level", k.str, k.len) == 0) {
-			/*
-			 * Between 0-9: level: see zlib manual.
-			 */
-			zlib_level = (int)v.val;
-			if (zlib_level < 0 || zlib_level > 9) {
-				(void)wt_api->err_printf(wt_api, NULL,
-				    "WT_CONFIG_PARSER.next: zlib configure: "
-				    "unsupported compression level %d",
-				    zlib_level);
-				return (EINVAL);
-			}
-			*zlib_levelp = zlib_level;
-			continue;
+	if ((ret = wt_api->config_get(
+	    wt_api, NULL, config, "compression_level", &v)) == 0) {
+		/*
+		 * Between 0-9: level: see zlib manual.
+		 */
+		zlib_level = (int)v.val;
+		if (zlib_level < 0 || zlib_level > 9) {
+			(void)wt_api->err_printf(wt_api, NULL,
+			    "zlib_init_config: "
+			    "unsupported compression level %d",
+			    zlib_level);
+			return (EINVAL);
 		}
-	if (ret != WT_NOTFOUND) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_CONFIG_PARSER.next: zlib configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	if ((ret = config_parser->close(config_parser)) != 0) {
+		*zlib_levelp = zlib_level;
+	} else if (ret != WT_NOTFOUND) {
 		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_CONFIG_PARSER.close: zlib configure: %s",
+		    "zlib_init_config: %s",
 		    wt_api->strerror(wt_api, NULL, ret));
 		return (ret);
 	}
+
 	return (0);
 }
 
diff --git a/ext/compressors/zstd/zstd_compress.c b/ext/compressors/zstd/zstd_compress.c
index a459b01d60a..ea8ec97602f 100644
--- a/ext/compressors/zstd/zstd_compress.c
+++ b/ext/compressors/zstd/zstd_compress.c
@@ -232,8 +232,7 @@ static int
 zstd_init_config(
     WT_CONNECTION *connection, WT_CONFIG_ARG *config, int *compression_levelp)
 {
-	WT_CONFIG_ITEM k, v;
-	WT_CONFIG_PARSER *config_parser;
+	WT_CONFIG_ITEM v;
 	WT_EXTENSION_API *wt_api;
 	int ret;
 
@@ -246,38 +245,16 @@ zstd_init_config(
 	 * level; review the configuration.
 	 */
 	wt_api = connection->get_extension_api(connection);
-	if ((ret =
-	    wt_api->config_get(wt_api, NULL, config, "config", &v)) != 0) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_EXTENSION_API.config_get: zstd configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	if ((ret = wt_api->config_parser_open(
-	    wt_api, NULL, v.str, v.len, &config_parser)) != 0) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_EXTENSION_API.config_parser_open: zstd configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	while ((ret = config_parser->next(config_parser, &k, &v)) == 0)
-		if (strlen("compression_level") == k.len &&
-		    strncmp("compression_level", k.str, k.len) == 0) {
-			*compression_levelp = (int)v.val;
-			continue;
-		}
-	if (ret != WT_NOTFOUND) {
+	if ((ret = wt_api->config_get(
+	    wt_api, NULL, config, "compression_level", &v)) == 0)
+		*compression_levelp = (int)v.val;
+	else if (ret != WT_NOTFOUND) {
 		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_CONFIG_PARSER.next: zstd configure: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-		return (ret);
-	}
-	if ((ret = config_parser->close(config_parser)) != 0) {
-		(void)wt_api->err_printf(wt_api, NULL,
-		    "WT_CONFIG_PARSER.close: zstd configure: %s",
+		    "zstd_init_config: %s",
 		    wt_api->strerror(wt_api, NULL, ret));
 		return (ret);
 	}
+
 	return (0);
 }
 
diff --git a/ext/datasources/helium/helium.c b/ext/datasources/helium/helium.c
index 473c569f0cc..dff86bd73ac 100644
--- a/ext/datasources/helium/helium.c
+++ b/ext/datasources/helium/helium.c
@@ -3380,15 +3380,9 @@ wiredtiger_extension_init(WT_CONNECTION *connection, WT_CONFIG_ARG *config)
 		goto err;
 	ds->lockinit = 1;
 
-	/* Get the configuration string. */
-	if ((ret = wt_api->config_get(wt_api, NULL, config, "config", &v)) != 0)
-		EMSG_ERR(wt_api, NULL, ret,
-		    "WT_EXTENSION_API.config_get: config: %s",
-		    wt_api->strerror(wt_api, NULL, ret));
-
 	/* Step through the list of Helium sources, opening each one. */
-	if ((ret = wt_api->config_parser_open(
-	    wt_api, NULL, v.str, v.len, &config_parser)) != 0)
+	if ((ret = wt_api->config_parser_open_arg(
+	    wt_api, NULL, config, &config_parser)) != 0)
 		EMSG_ERR(wt_api, NULL, ret,
 		    "WT_EXTENSION_API.config_parser_open: config: %s",
 		    wt_api->strerror(wt_api, NULL, ret));
diff --git a/ext/encryptors/rotn/rotn_encrypt.c b/ext/encryptors/rotn/rotn_encrypt.c
index 559c8e6e33a..0b905a0540d 100644
--- a/ext/encryptors/rotn/rotn_encrypt.c
+++ b/ext/encryptors/rotn/rotn_encrypt.c
@@ -76,7 +76,7 @@ typedef struct {
 	u_char *shift_forw;		/* Encrypt shift data from secretkey */
 	u_char *shift_back;		/* Decrypt shift data from secretkey */
 	size_t shift_len;		/* Length of shift* byte arrays */
-	int force_error;		/* Force a decrypt error for testing */
+	bool force_error;		/* Force a decrypt error for testing */
 
 } ROTN_ENCRYPTOR;
 /*! [WT_ENCRYPTOR initialization structure] */
@@ -429,43 +429,19 @@ rotn_terminate(WT_ENCRYPTOR *encryptor, WT_SESSION *session)
 static int
 rotn_configure(ROTN_ENCRYPTOR *rotn_encryptor, WT_CONFIG_ARG *config)
 {
-	WT_CONFIG_ITEM k, v;
-	WT_CONFIG_PARSER *config_parser;
+	WT_CONFIG_ITEM v;
 	WT_EXTENSION_API *wt_api;	/* Extension API */
-	int ret, t_ret;
+	int ret;
 
 	wt_api = rotn_encryptor->wt_api;
 
 	/* Get the configuration string. */
-	if ((ret = wt_api->config_get(wt_api, NULL, config, "config", &v)) != 0)
-		return (rotn_error(rotn_encryptor, NULL, ret,
-		    "WT_EXTENSION_API.config_get"));
-
-	/* Step through the list of configuration options. */
-	if ((ret = wt_api->config_parser_open(
-	    wt_api, NULL, v.str, v.len, &config_parser)) != 0)
-		return (rotn_error(rotn_encryptor, NULL, ret,
-		    "WT_EXTENSION_API.config_parser_open"));
-
-	while ((ret = config_parser->next(config_parser, &k, &v)) == 0) {
-		if (strncmp("rotn_force_error", k.str, k.len) == 0 &&
-		    strlen("rotn_force_error") == k.len) {
-			rotn_encryptor->force_error = v.val == 0 ? 0 : 1;
-			continue;
-		} else {
-			if ((ret = config_parser->close(config_parser)) != 0)
-				return (rotn_error(rotn_encryptor,
-				    NULL, ret, "WT_CONFIG_PARSER.close"));
-			return (rotn_error(rotn_encryptor, NULL, EINVAL,
-			    "unknown config key"));
-		}
-	}
-	if ((t_ret = config_parser->close(config_parser)) != 0)
-		return (rotn_error(rotn_encryptor, NULL, t_ret,
-		    "WT_CONFIG_PARSER.close"));
-	if (ret != WT_NOTFOUND)
-		return (rotn_error(rotn_encryptor, NULL, ret,
-		    "WT_CONFIG_PARSER.next"));
+	if ((ret = wt_api->config_get(
+	    wt_api, NULL, config, "rotn_force_error", &v)) == 0)
+		rotn_encryptor->force_error = v.val != 0;
+	else if (ret != WT_NOTFOUND)
+		return (rotn_error(rotn_encryptor, NULL, EINVAL,
+		    "error parsing config"));
 
 	return (0);
 }
diff --git a/src/block/block_ckpt.c b/src/block/block_ckpt.c
index 48522768dc9..05e4dcc098e 100644
--- a/src/block/block_ckpt.c
+++ b/src/block/block_ckpt.c
@@ -53,7 +53,6 @@ __wt_block_checkpoint_load(WT_SESSION_IMPL *session, WT_BLOCK *block,
 	WT_DECL_RET;
 	uint8_t *endp;
 
-	WT_UNUSED(addr_size);
 	ci = NULL;
 
 	/*
diff --git a/src/block/block_read.c b/src/block/block_read.c
index 1eeabd63d92..869a92b6ae1 100644
--- a/src/block/block_read.c
+++ b/src/block/block_read.c
@@ -24,8 +24,6 @@ __wt_bm_preload(
 	uint32_t checksum, size;
 	bool mapped;
 
-	WT_UNUSED(addr_size);
-
 	block = bm->block;
 
 	WT_STAT_CONN_INCR(session, block_preload);
diff --git a/src/block/block_slvg.c b/src/block/block_slvg.c
index 5ba95bb598e..b06a5062f50 100644
--- a/src/block/block_slvg.c
+++ b/src/block/block_slvg.c
@@ -168,7 +168,6 @@ __wt_block_salvage_valid(WT_SESSION_IMPL *session,
 	wt_off_t offset;
 	uint32_t size, checksum;
 
-	WT_UNUSED(session);
 	WT_UNUSED(addr_size);
 
 	/*
diff --git a/src/btree/bt_cursor.c b/src/btree/bt_cursor.c
index 0454ea7c20e..a996b21f7ce 100644
--- a/src/btree/bt_cursor.c
+++ b/src/btree/bt_cursor.c
@@ -325,7 +325,7 @@ __wt_btcur_search(WT_CURSOR_BTREE *cbt)
 	valid = false;
 	if (F_ISSET(cbt, WT_CBT_ACTIVE) &&
 	    cbt->ref->page->read_gen != WT_READGEN_OLDEST) {
-		WT_ERR(__wt_txn_cursor_op(session));
+		__wt_txn_cursor_op(session);
 
 		WT_ERR(btree->type == BTREE_ROW ?
 		    __cursor_row_search(session, cbt, cbt->ref, false) :
@@ -405,7 +405,7 @@ __wt_btcur_search_near(WT_CURSOR_BTREE *cbt, int *exactp)
 	if (btree->type == BTREE_ROW &&
 	    F_ISSET(cbt, WT_CBT_ACTIVE) &&
 	    cbt->ref->page->read_gen != WT_READGEN_OLDEST) {
-		WT_ERR(__wt_txn_cursor_op(session));
+		__wt_txn_cursor_op(session);
 
 		WT_ERR(__cursor_row_search(session, cbt, cbt->ref, true));
 
diff --git a/src/btree/bt_sync.c b/src/btree/bt_sync.c
index 6d4ad9d0d0f..129d7fec05f 100644
--- a/src/btree/bt_sync.c
+++ b/src/btree/bt_sync.c
@@ -133,7 +133,7 @@ __sync_file(WT_SESSION_IMPL *session, WT_CACHE_OP syncop)
 			if (__wt_page_is_modified(page) &&
 			    WT_TXNID_LT(page->modify->update_txn, oldest_id)) {
 				if (txn->isolation == WT_ISO_READ_COMMITTED)
-					WT_ERR(__wt_txn_get_snapshot(session));
+					__wt_txn_get_snapshot(session);
 				leaf_bytes += page->memory_footprint;
 				++leaf_pages;
 				WT_ERR(__wt_reconcile(
@@ -155,7 +155,7 @@ __sync_file(WT_SESSION_IMPL *session, WT_CACHE_OP syncop)
 		 * the checkpoint are included.
 		 */
 		if (txn->isolation == WT_ISO_READ_COMMITTED)
-			WT_ERR(__wt_txn_get_snapshot(session));
+			__wt_txn_get_snapshot(session);
 
 		/*
 		 * We cannot check the tree modified flag in the case of a
diff --git a/src/config/config.c b/src/config/config.c
index 3416153d160..a47dfe76aec 100644
--- a/src/config/config.c
+++ b/src/config/config.c
@@ -711,7 +711,7 @@ __wt_config_getones(WT_SESSION_IMPL *session,
 /*
  * __wt_config_getones_none --
  *	Get the value for a given string key from a single config string.
- * Treat "none" as empty.
+ *	Treat "none" as empty.
  */
 int
 __wt_config_getones_none(WT_SESSION_IMPL *session,
diff --git a/src/config/config_def.c b/src/config/config_def.c
index d57bc418c93..35fea16b1a5 100644
--- a/src/config/config_def.c
+++ b/src/config/config_def.c
@@ -24,6 +24,7 @@ static const WT_CONFIG_CHECK confchk_WT_CONNECTION_load_extension[] = {
 };
 
 static const WT_CONFIG_CHECK confchk_WT_CONNECTION_open_session[] = {
+	{ "ignore_cache_size", "boolean", NULL, NULL, NULL, 0 },
 	{ "isolation", "string",
 	    NULL, "choices=[\"read-uncommitted\",\"read-committed\","
 	    "\"snapshot\"]",
@@ -344,6 +345,7 @@ static const WT_CONFIG_CHECK confchk_WT_SESSION_open_cursor[] = {
 };
 
 static const WT_CONFIG_CHECK confchk_WT_SESSION_reconfigure[] = {
+	{ "ignore_cache_size", "boolean", NULL, NULL, NULL, 0 },
 	{ "isolation", "string",
 	    NULL, "choices=[\"read-uncommitted\",\"read-committed\","
 	    "\"snapshot\"]",
@@ -657,6 +659,7 @@ static const WT_CONFIG_CHECK confchk_wiredtiger_open[] = {
 	    NULL, NULL,
 	    confchk_wiredtiger_open_async_subconfigs, 3 },
 	{ "buffer_alignment", "int", NULL, "min=-1,max=1MB", NULL, 0 },
+	{ "builtin_extension_config", "string", NULL, NULL, NULL, 0 },
 	{ "cache_overhead", "int", NULL, "min=0,max=30", NULL, 0 },
 	{ "cache_size", "int", NULL, "min=1MB,max=10TB", NULL, 0 },
 	{ "checkpoint", "category",
@@ -742,6 +745,7 @@ static const WT_CONFIG_CHECK confchk_wiredtiger_open_all[] = {
 	    NULL, NULL,
 	    confchk_wiredtiger_open_async_subconfigs, 3 },
 	{ "buffer_alignment", "int", NULL, "min=-1,max=1MB", NULL, 0 },
+	{ "builtin_extension_config", "string", NULL, NULL, NULL, 0 },
 	{ "cache_overhead", "int", NULL, "min=0,max=30", NULL, 0 },
 	{ "cache_size", "int", NULL, "min=1MB,max=10TB", NULL, 0 },
 	{ "checkpoint", "category",
@@ -828,6 +832,7 @@ static const WT_CONFIG_CHECK confchk_wiredtiger_open_basecfg[] = {
 	    NULL, NULL,
 	    confchk_wiredtiger_open_async_subconfigs, 3 },
 	{ "buffer_alignment", "int", NULL, "min=-1,max=1MB", NULL, 0 },
+	{ "builtin_extension_config", "string", NULL, NULL, NULL, 0 },
 	{ "cache_overhead", "int", NULL, "min=0,max=30", NULL, 0 },
 	{ "cache_size", "int", NULL, "min=1MB,max=10TB", NULL, 0 },
 	{ "checkpoint", "category",
@@ -908,6 +913,7 @@ static const WT_CONFIG_CHECK confchk_wiredtiger_open_usercfg[] = {
 	    NULL, NULL,
 	    confchk_wiredtiger_open_async_subconfigs, 3 },
 	{ "buffer_alignment", "int", NULL, "min=-1,max=1MB", NULL, 0 },
+	{ "builtin_extension_config", "string", NULL, NULL, NULL, 0 },
 	{ "cache_overhead", "int", NULL, "min=0,max=30", NULL, 0 },
 	{ "cache_size", "int", NULL, "min=1MB,max=10TB", NULL, 0 },
 	{ "checkpoint", "category",
@@ -1017,8 +1023,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  confchk_WT_CONNECTION_load_extension, 4
 	},
 	{ "WT_CONNECTION.open_session",
-	  "isolation=read-committed",
-	  confchk_WT_CONNECTION_open_session, 1
+	  "ignore_cache_size=false,isolation=read-committed",
+	  confchk_WT_CONNECTION_open_session, 2
 	},
 	{ "WT_CONNECTION.reconfigure",
 	  "async=(enabled=false,ops_max=1024,threads=2),cache_overhead=8,"
@@ -1116,8 +1122,8 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  NULL, 0
 	},
 	{ "WT_SESSION.reconfigure",
-	  "isolation=read-committed",
-	  confchk_WT_SESSION_reconfigure, 1
+	  "ignore_cache_size=false,isolation=read-committed",
+	  confchk_WT_SESSION_reconfigure, 2
 	},
 	{ "WT_SESSION.rename",
 	  "",
@@ -1226,62 +1232,64 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	},
 	{ "wiredtiger_open",
 	  "async=(enabled=false,ops_max=1024,threads=2),buffer_alignment=-1"
-	  ",cache_overhead=8,cache_size=100MB,checkpoint=(log_size=0,"
-	  "wait=0),checkpoint_sync=true,config_base=true,create=false,"
-	  "direct_io=,encryption=(keyid=,name=,secretkey=),error_prefix=,"
-	  "eviction=(threads_max=1,threads_min=1),"
-	  "eviction_checkpoint_target=5,eviction_dirty_target=5,"
-	  "eviction_dirty_trigger=20,eviction_target=80,eviction_trigger=95"
-	  ",exclusive=false,extensions=,file_extend=,"
-	  "file_manager=(close_handle_minimum=250,close_idle_time=30,"
-	  "close_scan_interval=10),hazard_max=1000,in_memory=false,"
-	  "log=(archive=true,compressor=,enabled=false,file_max=100MB,"
-	  "path=\".\",prealloc=true,recover=on,zero_fill=false),"
-	  "lsm_manager=(merge=true,worker_thread_max=4),lsm_merge=true,"
-	  "mmap=true,multiprocess=false,readonly=false,session_max=100,"
-	  "session_scratch_max=2MB,shared_cache=(chunk=10MB,name=,quota=0,"
-	  "reserve=0,size=500MB),statistics=none,statistics_log=(json=false"
-	  ",on_close=false,path=\".\",sources=,timestamp=\"%b %d %H:%M:%S\""
-	  ",wait=0),transaction_sync=(enabled=false,method=fsync),"
+	  ",builtin_extension_config=,cache_overhead=8,cache_size=100MB,"
+	  "checkpoint=(log_size=0,wait=0),checkpoint_sync=true,"
+	  "config_base=true,create=false,direct_io=,encryption=(keyid=,"
+	  "name=,secretkey=),error_prefix=,eviction=(threads_max=1,"
+	  "threads_min=1),eviction_checkpoint_target=5,"
+	  "eviction_dirty_target=5,eviction_dirty_trigger=20,"
+	  "eviction_target=80,eviction_trigger=95,exclusive=false,"
+	  "extensions=,file_extend=,file_manager=(close_handle_minimum=250,"
+	  "close_idle_time=30,close_scan_interval=10),hazard_max=1000,"
+	  "in_memory=false,log=(archive=true,compressor=,enabled=false,"
+	  "file_max=100MB,path=\".\",prealloc=true,recover=on,"
+	  "zero_fill=false),lsm_manager=(merge=true,worker_thread_max=4),"
+	  "lsm_merge=true,mmap=true,multiprocess=false,readonly=false,"
+	  "session_max=100,session_scratch_max=2MB,shared_cache=(chunk=10MB"
+	  ",name=,quota=0,reserve=0,size=500MB),statistics=none,"
+	  "statistics_log=(json=false,on_close=false,path=\".\",sources=,"
+	  "timestamp=\"%b %d %H:%M:%S\",wait=0),"
+	  "transaction_sync=(enabled=false,method=fsync),"
 	  "use_environment=true,use_environment_priv=false,verbose=,"
 	  "write_through=",
-	  confchk_wiredtiger_open, 39
+	  confchk_wiredtiger_open, 40
 	},
 	{ "wiredtiger_open_all",
 	  "async=(enabled=false,ops_max=1024,threads=2),buffer_alignment=-1"
-	  ",cache_overhead=8,cache_size=100MB,checkpoint=(log_size=0,"
-	  "wait=0),checkpoint_sync=true,config_base=true,create=false,"
-	  "direct_io=,encryption=(keyid=,name=,secretkey=),error_prefix=,"
-	  "eviction=(threads_max=1,threads_min=1),"
-	  "eviction_checkpoint_target=5,eviction_dirty_target=5,"
-	  "eviction_dirty_trigger=20,eviction_target=80,eviction_trigger=95"
-	  ",exclusive=false,extensions=,file_extend=,"
-	  "file_manager=(close_handle_minimum=250,close_idle_time=30,"
-	  "close_scan_interval=10),hazard_max=1000,in_memory=false,"
-	  "log=(archive=true,compressor=,enabled=false,file_max=100MB,"
-	  "path=\".\",prealloc=true,recover=on,zero_fill=false),"
-	  "lsm_manager=(merge=true,worker_thread_max=4),lsm_merge=true,"
-	  "mmap=true,multiprocess=false,readonly=false,session_max=100,"
-	  "session_scratch_max=2MB,shared_cache=(chunk=10MB,name=,quota=0,"
-	  "reserve=0,size=500MB),statistics=none,statistics_log=(json=false"
-	  ",on_close=false,path=\".\",sources=,timestamp=\"%b %d %H:%M:%S\""
-	  ",wait=0),transaction_sync=(enabled=false,method=fsync),"
+	  ",builtin_extension_config=,cache_overhead=8,cache_size=100MB,"
+	  "checkpoint=(log_size=0,wait=0),checkpoint_sync=true,"
+	  "config_base=true,create=false,direct_io=,encryption=(keyid=,"
+	  "name=,secretkey=),error_prefix=,eviction=(threads_max=1,"
+	  "threads_min=1),eviction_checkpoint_target=5,"
+	  "eviction_dirty_target=5,eviction_dirty_trigger=20,"
+	  "eviction_target=80,eviction_trigger=95,exclusive=false,"
+	  "extensions=,file_extend=,file_manager=(close_handle_minimum=250,"
+	  "close_idle_time=30,close_scan_interval=10),hazard_max=1000,"
+	  "in_memory=false,log=(archive=true,compressor=,enabled=false,"
+	  "file_max=100MB,path=\".\",prealloc=true,recover=on,"
+	  "zero_fill=false),lsm_manager=(merge=true,worker_thread_max=4),"
+	  "lsm_merge=true,mmap=true,multiprocess=false,readonly=false,"
+	  "session_max=100,session_scratch_max=2MB,shared_cache=(chunk=10MB"
+	  ",name=,quota=0,reserve=0,size=500MB),statistics=none,"
+	  "statistics_log=(json=false,on_close=false,path=\".\",sources=,"
+	  "timestamp=\"%b %d %H:%M:%S\",wait=0),"
+	  "transaction_sync=(enabled=false,method=fsync),"
 	  "use_environment=true,use_environment_priv=false,verbose=,"
 	  "version=(major=0,minor=0),write_through=",
-	  confchk_wiredtiger_open_all, 40
+	  confchk_wiredtiger_open_all, 41
 	},
 	{ "wiredtiger_open_basecfg",
 	  "async=(enabled=false,ops_max=1024,threads=2),buffer_alignment=-1"
-	  ",cache_overhead=8,cache_size=100MB,checkpoint=(log_size=0,"
-	  "wait=0),checkpoint_sync=true,direct_io=,encryption=(keyid=,name="
-	  ",secretkey=),error_prefix=,eviction=(threads_max=1,"
-	  "threads_min=1),eviction_checkpoint_target=5,"
-	  "eviction_dirty_target=5,eviction_dirty_trigger=20,"
-	  "eviction_target=80,eviction_trigger=95,extensions=,file_extend=,"
-	  "file_manager=(close_handle_minimum=250,close_idle_time=30,"
-	  "close_scan_interval=10),hazard_max=1000,log=(archive=true,"
-	  "compressor=,enabled=false,file_max=100MB,path=\".\","
-	  "prealloc=true,recover=on,zero_fill=false),"
+	  ",builtin_extension_config=,cache_overhead=8,cache_size=100MB,"
+	  "checkpoint=(log_size=0,wait=0),checkpoint_sync=true,direct_io=,"
+	  "encryption=(keyid=,name=,secretkey=),error_prefix=,"
+	  "eviction=(threads_max=1,threads_min=1),"
+	  "eviction_checkpoint_target=5,eviction_dirty_target=5,"
+	  "eviction_dirty_trigger=20,eviction_target=80,eviction_trigger=95"
+	  ",extensions=,file_extend=,file_manager=(close_handle_minimum=250"
+	  ",close_idle_time=30,close_scan_interval=10),hazard_max=1000,"
+	  "log=(archive=true,compressor=,enabled=false,file_max=100MB,"
+	  "path=\".\",prealloc=true,recover=on,zero_fill=false),"
 	  "lsm_manager=(merge=true,worker_thread_max=4),lsm_merge=true,"
 	  "mmap=true,multiprocess=false,readonly=false,session_max=100,"
 	  "session_scratch_max=2MB,shared_cache=(chunk=10MB,name=,quota=0,"
@@ -1289,20 +1297,20 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  ",on_close=false,path=\".\",sources=,timestamp=\"%b %d %H:%M:%S\""
 	  ",wait=0),transaction_sync=(enabled=false,method=fsync),verbose=,"
 	  "version=(major=0,minor=0),write_through=",
-	  confchk_wiredtiger_open_basecfg, 34
+	  confchk_wiredtiger_open_basecfg, 35
 	},
 	{ "wiredtiger_open_usercfg",
 	  "async=(enabled=false,ops_max=1024,threads=2),buffer_alignment=-1"
-	  ",cache_overhead=8,cache_size=100MB,checkpoint=(log_size=0,"
-	  "wait=0),checkpoint_sync=true,direct_io=,encryption=(keyid=,name="
-	  ",secretkey=),error_prefix=,eviction=(threads_max=1,"
-	  "threads_min=1),eviction_checkpoint_target=5,"
-	  "eviction_dirty_target=5,eviction_dirty_trigger=20,"
-	  "eviction_target=80,eviction_trigger=95,extensions=,file_extend=,"
-	  "file_manager=(close_handle_minimum=250,close_idle_time=30,"
-	  "close_scan_interval=10),hazard_max=1000,log=(archive=true,"
-	  "compressor=,enabled=false,file_max=100MB,path=\".\","
-	  "prealloc=true,recover=on,zero_fill=false),"
+	  ",builtin_extension_config=,cache_overhead=8,cache_size=100MB,"
+	  "checkpoint=(log_size=0,wait=0),checkpoint_sync=true,direct_io=,"
+	  "encryption=(keyid=,name=,secretkey=),error_prefix=,"
+	  "eviction=(threads_max=1,threads_min=1),"
+	  "eviction_checkpoint_target=5,eviction_dirty_target=5,"
+	  "eviction_dirty_trigger=20,eviction_target=80,eviction_trigger=95"
+	  ",extensions=,file_extend=,file_manager=(close_handle_minimum=250"
+	  ",close_idle_time=30,close_scan_interval=10),hazard_max=1000,"
+	  "log=(archive=true,compressor=,enabled=false,file_max=100MB,"
+	  "path=\".\",prealloc=true,recover=on,zero_fill=false),"
 	  "lsm_manager=(merge=true,worker_thread_max=4),lsm_merge=true,"
 	  "mmap=true,multiprocess=false,readonly=false,session_max=100,"
 	  "session_scratch_max=2MB,shared_cache=(chunk=10MB,name=,quota=0,"
@@ -1310,7 +1318,7 @@ static const WT_CONFIG_ENTRY config_entries[] = {
 	  ",on_close=false,path=\".\",sources=,timestamp=\"%b %d %H:%M:%S\""
 	  ",wait=0),transaction_sync=(enabled=false,method=fsync),verbose=,"
 	  "write_through=",
-	  confchk_wiredtiger_open_usercfg, 33
+	  confchk_wiredtiger_open_usercfg, 34
 	},
 	{ NULL, NULL, NULL, 0 }
 };
diff --git a/src/config/config_ext.c b/src/config/config_ext.c
index 56c0018f8c3..88f1390843a 100644
--- a/src/config/config_ext.c
+++ b/src/config/config_ext.c
@@ -9,22 +9,9 @@
 #include "wt_internal.h"
 
 /*
- * __wt_ext_config_parser_open --
- *	WT_EXTENSION_API->config_parser_open implementation
- */
-int
-__wt_ext_config_parser_open(WT_EXTENSION_API *wt_ext, WT_SESSION *wt_session,
-    const char *config, size_t len, WT_CONFIG_PARSER **config_parserp)
-{
-	WT_UNUSED(wt_ext);
-	return (wiredtiger_config_parser_open(
-	    wt_session, config, len, config_parserp));
-}
-
-/*
  * __wt_ext_config_get --
  *	Given a NULL-terminated list of configuration strings, find the final
- * value for a given string key (external API version).
+ *	value for a given string key (external API version).
  */
 int
 __wt_ext_config_get(WT_EXTENSION_API *wt_api,
@@ -43,3 +30,65 @@ __wt_ext_config_get(WT_EXTENSION_API *wt_api,
 		return (WT_NOTFOUND);
 	return (__wt_config_gets(session, cfg, key, cval));
 }
+
+/*
+ * __wt_ext_config_get_string --
+ *	Given a configuration string, find the value for a given string key
+ *	(external API version).
+ */
+int
+__wt_ext_config_get_string(WT_EXTENSION_API *wt_api,
+    WT_SESSION *wt_session, const char *config, const char *key,
+    WT_CONFIG_ITEM *cval)
+{
+	WT_CONNECTION_IMPL *conn;
+	WT_SESSION_IMPL *session;
+
+	conn = (WT_CONNECTION_IMPL *)wt_api->conn;
+	if ((session = (WT_SESSION_IMPL *)wt_session) == NULL)
+		session = conn->default_session;
+
+	return (__wt_config_getones(session, config, key, cval));
+}
+
+/*
+ * __wt_ext_config_parser_open --
+ *	WT_EXTENSION_API->config_parser_open implementation
+ */
+int
+__wt_ext_config_parser_open(WT_EXTENSION_API *wt_ext, WT_SESSION *wt_session,
+    const char *config, size_t len, WT_CONFIG_PARSER **config_parserp)
+{
+	WT_UNUSED(wt_ext);
+	return (wiredtiger_config_parser_open(
+	    wt_session, config, len, config_parserp));
+}
+
+/*
+ * __wt_ext_config_parser_open_arg --
+ *	WT_EXTENSION_API->config_parser_open_arg implementation
+ */
+int
+__wt_ext_config_parser_open_arg(WT_EXTENSION_API *wt_ext,
+    WT_SESSION *wt_session, WT_CONFIG_ARG *cfg_arg,
+    WT_CONFIG_PARSER **config_parserp)
+{
+	const char **cfg, *p;
+	size_t len;
+
+	WT_UNUSED(wt_ext);
+
+	/* Find the last non-NULL entry in the configuration stack. */
+	if ((cfg = (const char **)cfg_arg) == NULL || *cfg == NULL) {
+		p = NULL;
+		len = 0;
+	} else {
+		while (cfg[1] != NULL)
+			++cfg;
+		p = *cfg;
+		len = strlen(p);
+	}
+
+	return (wiredtiger_config_parser_open(
+	    wt_session, p, len, config_parserp));
+}
diff --git a/src/conn/conn_api.c b/src/conn/conn_api.c
index a6e0f57f02e..1bc4a501ce2 100644
--- a/src/conn/conn_api.c
+++ b/src/conn/conn_api.c
@@ -239,8 +239,6 @@ __conn_add_compressor(WT_CONNECTION *wt_conn,
 	WT_NAMED_COMPRESSOR *ncomp;
 	WT_SESSION_IMPL *session;
 
-	WT_UNUSED(name);
-	WT_UNUSED(compressor);
 	ncomp = NULL;
 
 	conn = (WT_CONNECTION_IMPL *)wt_conn;
@@ -756,8 +754,11 @@ __conn_get_extension_api(WT_CONNECTION *wt_conn)
 	conn->extension_api.scr_free = __wt_ext_scr_free;
 	conn->extension_api.collator_config = ext_collator_config;
 	conn->extension_api.collate = ext_collate;
-	conn->extension_api.config_parser_open = __wt_ext_config_parser_open;
 	conn->extension_api.config_get = __wt_ext_config_get;
+	conn->extension_api.config_get_string = __wt_ext_config_get_string;
+	conn->extension_api.config_parser_open = __wt_ext_config_parser_open;
+	conn->extension_api.config_parser_open_arg =
+	    __wt_ext_config_parser_open_arg;
 	conn->extension_api.metadata_insert = __wt_ext_metadata_insert;
 	conn->extension_api.metadata_remove = __wt_ext_metadata_remove;
 	conn->extension_api.metadata_search = __wt_ext_metadata_search;
@@ -789,40 +790,75 @@ __conn_get_extension_api(WT_CONNECTION *wt_conn)
 	return (&conn->extension_api);
 }
 
+/*
+ * __conn_builtin_init --
+ *	Initialize and configure a builtin extension.
+ */
+static int
+__conn_builtin_init(WT_CONNECTION_IMPL *conn, const char *name,
+    int (*extension_init)(WT_CONNECTION *, WT_CONFIG_ARG *),
+    const char *cfg[])
+{
+	WT_CONFIG_ITEM all_configs, cval;
+	WT_DECL_RET;
+	WT_SESSION_IMPL *session;
+	char *config;
+	const char *ext_cfg[] = { NULL, NULL };
+
+	session = conn->default_session;
+
+	WT_RET(__wt_config_gets(
+	    session, cfg, "builtin_extension_config", &all_configs));
+	WT_CLEAR(cval);
+	WT_RET_NOTFOUND_OK(__wt_config_subgets(
+	    session, &all_configs, name, &cval));
+	WT_RET(__wt_strndup(session, cval.str, cval.len, &config));
+	ext_cfg[0] = config;
+
+	ret = extension_init(&conn->iface, (WT_CONFIG_ARG *)ext_cfg);
+	__wt_free(session, config);
+
+	return (ret);
+}
+
 #ifdef HAVE_BUILTIN_EXTENSION_LZ4
-	extern int lz4_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
+extern int lz4_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_SNAPPY
-	extern int snappy_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
+extern int snappy_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_ZLIB
-	extern int zlib_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
+extern int zlib_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_ZSTD
-	extern int zstd_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
+extern int zstd_extension_init(WT_CONNECTION *, WT_CONFIG_ARG *);
 #endif
 
 /*
- * __conn_load_default_extensions --
+ * __conn_builtin_extensions --
  *	Load extensions that are enabled via --with-builtins
  */
 static int
-__conn_load_default_extensions(WT_CONNECTION_IMPL *conn)
+__conn_builtin_extensions(WT_CONNECTION_IMPL *conn, const char *cfg[])
 {
-	WT_UNUSED(conn);
-
 #ifdef HAVE_BUILTIN_EXTENSION_LZ4
-	WT_RET(lz4_extension_init(&conn->iface, NULL));
+	WT_RET(__conn_builtin_init(conn, "lz4", lz4_extension_init, cfg));
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_SNAPPY
-	WT_RET(snappy_extension_init(&conn->iface, NULL));
+	WT_RET(__conn_builtin_init(conn, "snappy", snappy_extension_init, cfg));
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_ZLIB
-	WT_RET(zlib_extension_init(&conn->iface, NULL));
+	WT_RET(__conn_builtin_init(conn, "zlib", zlib_extension_init, cfg));
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_ZSTD
-	WT_RET(zstd_extension_init(&conn->iface, NULL));
+	WT_RET(__conn_builtin_init(conn, "zstd", zstd_extension_init, cfg));
 #endif
+
+	/* Avoid warnings if no builtin extensions are configured. */
+	WT_UNUSED(conn);
+	WT_UNUSED(cfg);
+	WT_UNUSED(__conn_builtin_init);
+
 	return (0);
 }
 
@@ -839,10 +875,11 @@ __conn_load_extension_int(WT_SESSION_IMPL *session,
 	WT_DLH *dlh;
 	int (*load)(WT_CONNECTION *, WT_CONFIG_ARG *);
 	bool is_local;
-	const char *init_name, *terminate_name;
+	const char *ext_config, *init_name, *terminate_name;
+	const char *ext_cfg[2];
 
 	dlh = NULL;
-	init_name = terminate_name = NULL;
+	ext_config = init_name = terminate_name = NULL;
 	is_local = strcmp(path, "local") == 0;
 
 	/* Ensure that the load matches the phase of startup we are in. */
@@ -872,8 +909,14 @@ __conn_load_extension_int(WT_SESSION_IMPL *session,
 	WT_ERR(
 	    __wt_dlsym(session, dlh, terminate_name, false, &dlh->terminate));
 
+	WT_CLEAR(cval);
+	WT_ERR_NOTFOUND_OK(__wt_config_gets(session, cfg, "config", &cval));
+	WT_ERR(__wt_strndup(session, cval.str, cval.len, &ext_config));
+	ext_cfg[0] = ext_config;
+	ext_cfg[1] = NULL;
+
 	/* Call the load function last, it simplifies error handling. */
-	WT_ERR(load(&S2C(session)->iface, (WT_CONFIG_ARG *)cfg));
+	WT_ERR(load(&S2C(session)->iface, (WT_CONFIG_ARG *)ext_cfg));
 
 	/* Link onto the environment's list of open libraries. */
 	__wt_spin_lock(session, &S2C(session)->api_lock);
@@ -883,6 +926,7 @@ __conn_load_extension_int(WT_SESSION_IMPL *session,
 
 err:	if (dlh != NULL)
 		WT_TRET(__wt_dlclose(session, dlh));
+	__wt_free(session, ext_config);
 	__wt_free(session, init_name);
 	__wt_free(session, terminate_name);
 	return (ret);
@@ -2355,7 +2399,7 @@ wiredtiger_open(const char *home, WT_EVENT_HANDLER *event_handler,
 	 * everything else to be in place, and the extensions call back into the
 	 * library.
 	 */
-	WT_ERR(__conn_load_default_extensions(conn));
+	WT_ERR(__conn_builtin_extensions(conn, cfg));
 	WT_ERR(__conn_load_extensions(session, cfg, false));
 
 	/*
diff --git a/src/cursor/cur_config.c b/src/cursor/cur_config.c
index 2d3f3ffd176..4001188e21c 100644
--- a/src/cursor/cur_config.c
+++ b/src/cursor/cur_config.c
@@ -49,8 +49,6 @@ __wt_curconfig_open(WT_SESSION_IMPL *session,
 
 	WT_STATIC_ASSERT(offsetof(WT_CURSOR_CONFIG, iface) == 0);
 
-	WT_UNUSED(uri);
-
 	WT_RET(__wt_calloc_one(session, &cconfig));
 
 	cursor = &cconfig->iface;
diff --git a/src/cursor/cur_ds.c b/src/cursor/cur_ds.c
index 458e0f1b1f0..131d1ffa930 100644
--- a/src/cursor/cur_ds.c
+++ b/src/cursor/cur_ds.c
@@ -12,13 +12,11 @@
  * __curds_txn_enter --
  *	Do transactional initialization when starting an operation.
  */
-static int
+static void
 __curds_txn_enter(WT_SESSION_IMPL *session)
 {
 	session->ncursors++;				/* XXX */
-	WT_RET(__wt_txn_cursor_op(session));
-
-	return (0);
+	__wt_txn_cursor_op(session);
 }
 
 /*
@@ -187,7 +185,7 @@ __curds_next(WT_CURSOR *cursor)
 	WT_STAT_CONN_INCR(session, cursor_next);
 	WT_STAT_DATA_INCR(session, cursor_next);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	F_CLR(cursor, WT_CURSTD_KEY_SET | WT_CURSTD_VALUE_SET);
 	ret = __curds_cursor_resolve(cursor, source->next(source));
@@ -215,7 +213,7 @@ __curds_prev(WT_CURSOR *cursor)
 	WT_STAT_CONN_INCR(session, cursor_prev);
 	WT_STAT_DATA_INCR(session, cursor_prev);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	F_CLR(cursor, WT_CURSTD_KEY_SET | WT_CURSTD_VALUE_SET);
 	ret = __curds_cursor_resolve(cursor, source->prev(source));
@@ -267,7 +265,7 @@ __curds_search(WT_CURSOR *cursor)
 	WT_STAT_CONN_INCR(session, cursor_search);
 	WT_STAT_DATA_INCR(session, cursor_search);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	WT_ERR(__curds_key_set(cursor));
 	ret = __curds_cursor_resolve(cursor, source->search(source));
@@ -295,7 +293,7 @@ __curds_search_near(WT_CURSOR *cursor, int *exact)
 	WT_STAT_CONN_INCR(session, cursor_search_near);
 	WT_STAT_DATA_INCR(session, cursor_search_near);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	WT_ERR(__curds_key_set(cursor));
 	ret =
@@ -321,7 +319,7 @@ __curds_insert(WT_CURSOR *cursor)
 
 	CURSOR_UPDATE_API_CALL(cursor, session, insert, NULL);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	WT_STAT_CONN_INCR(session, cursor_insert);
 	WT_STAT_DATA_INCR(session, cursor_insert);
@@ -358,7 +356,7 @@ __curds_update(WT_CURSOR *cursor)
 	WT_STAT_DATA_INCR(session, cursor_update);
 	WT_STAT_DATA_INCRV(session, cursor_update_bytes, cursor->value.size);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	WT_ERR(__curds_key_set(cursor));
 	WT_ERR(__curds_value_set(cursor));
@@ -389,7 +387,7 @@ __curds_remove(WT_CURSOR *cursor)
 	WT_STAT_DATA_INCR(session, cursor_remove);
 	WT_STAT_DATA_INCRV(session, cursor_remove_bytes, cursor->key.size);
 
-	WT_ERR(__curds_txn_enter(session));
+	__curds_txn_enter(session);
 
 	WT_ERR(__curds_key_set(cursor));
 	ret = __curds_cursor_resolve(cursor, source->remove(source));
diff --git a/src/cursor/cur_join.c b/src/cursor/cur_join.c
index 806436ebf38..2fa2a207c8a 100644
--- a/src/cursor/cur_join.c
+++ b/src/cursor/cur_join.c
@@ -326,8 +326,7 @@ __curjoin_close(WT_CURSOR *cursor)
 	JOINABLE_CURSOR_API_CALL(cursor, session, close, NULL);
 
 	__wt_schema_release_table(session, cjoin->table);
-	/* These are owned by the table */
-	cursor->internal_uri = NULL;
+	/* This is owned by the table */
 	cursor->key_format = NULL;
 	if (cjoin->projection != NULL) {
 		__wt_free(session, cjoin->projection);
@@ -921,7 +920,7 @@ __curjoin_init_next(WT_SESSION_IMPL *session, WT_CURSOR_JOIN *cjoin,
 		    "cursors");
 
 	/* Get a consistent view of our subordinate cursors if appropriate. */
-	WT_RET(__wt_txn_cursor_op(session));
+	__wt_txn_cursor_op(session);
 
 	if (F_ISSET((WT_CURSOR *)cjoin, WT_CURSTD_RAW))
 		config = &raw_cfg[0];
@@ -1310,11 +1309,10 @@ __wt_curjoin_open(WT_SESSION_IMPL *session,
 		WT_RET_MSG(session, EINVAL,
 		    "unable to initialize a join cursor with existing owner");
 
-	if (!WT_PREFIX_SKIP(uri, "join:"))
-		return (__wt_unexpected_object_type(session, uri, "join:"));
 	tablename = uri;
-	if (!WT_PREFIX_SKIP(tablename, "table:"))
-		return (__wt_unexpected_object_type(session, uri, "table:"));
+	if (!WT_PREFIX_SKIP(tablename, "join:table:"))
+		return (
+		    __wt_unexpected_object_type(session, uri, "join:table:"));
 
 	columns = strchr(tablename, '(');
 	if (columns == NULL)
@@ -1327,7 +1325,6 @@ __wt_curjoin_open(WT_SESSION_IMPL *session,
 	cursor = &cjoin->iface;
 	*cursor = iface;
 	cursor->session = &session->iface;
-	cursor->internal_uri = table->name;
 	cursor->key_format = table->key_format;
 	cursor->value_format = table->value_format;
 	cjoin->table = table;
diff --git a/src/cursor/cur_json.c b/src/cursor/cur_json.c
index 093ec3c59ac..4ba10ddabb0 100644
--- a/src/cursor/cur_json.c
+++ b/src/cursor/cur_json.c
@@ -420,7 +420,8 @@ __wt_json_column_init(WT_CURSOR *cursor, const char *keyformat,
 		const char *_bad = in;					\
 		while (__wt_isalnum((u_char)*in))			\
 			in++;						\
-		__wt_errx(session, "unknown keyword \"%.*s\" in JSON",	\
+		WT_RET_MSG(session, EINVAL,				\
+		    "unknown keyword \"%.*s\" in JSON",			\
 		    (int)(in - _bad), _bad);				\
 	}								\
 } while (0)
@@ -501,9 +502,9 @@ __wt_json_token(WT_SESSION *wt_session, const char *src, int *toktype,
 			}
 			src++;
 		}
-		if (result != 's')
-			__wt_errx(session, "unterminated string in JSON");
-		break;
+		if (result == 's')
+			break;
+		WT_RET_MSG(session, EINVAL, "unterminated string in JSON");
 	case '-':
 	case '0':
 	case '1':
@@ -561,15 +562,14 @@ __wt_json_token(WT_SESSION *wt_session, const char *src, int *toktype,
 		if (isalph)
 			while (*src != '\0' && __wt_isalnum((u_char)*src))
 				src++;
-		__wt_errx(session, "unknown token \"%.*s\" in JSON",
-		    (int)(src - bad), bad);
-		break;
+		WT_RET_MSG(session, EINVAL,
+		    "unknown token \"%.*s\" in JSON", (int)(src - bad), bad);
+		/* NOTREACHED */
 	}
+	WT_ASSERT(session, result != -1);
+
 	*toklen = (size_t)(src - *tokstart);
 	*toktype = result;
-
-	if (result < 0)
-		WT_RET_MSG(session, EINVAL, "illegal token in JSON");
 	return (0);
 }
 
diff --git a/src/include/btree.h b/src/include/btree.h
index 713d46ae85f..0e0f7b4c40a 100644
--- a/src/include/btree.h
+++ b/src/include/btree.h
@@ -158,15 +158,16 @@ struct __wt_btree {
 #define	WT_BTREE_IGNORE_CACHE	0x000200 /* Cache-resident object */
 #define	WT_BTREE_IN_MEMORY	0x000400 /* Cache-resident object */
 #define	WT_BTREE_LOOKASIDE	0x000800 /* Look-aside table */
-#define	WT_BTREE_NO_CHECKPOINT	0x001000 /* Disable checkpoints */
-#define	WT_BTREE_NO_EVICTION	0x002000 /* Disable eviction */
-#define	WT_BTREE_NO_LOGGING	0x004000 /* Disable logging */
-#define	WT_BTREE_NO_RECONCILE	0x008000 /* Allow splits, even with no evict */
-#define	WT_BTREE_REBALANCE	0x010000 /* Handle is for rebalance */
-#define	WT_BTREE_SALVAGE	0x020000 /* Handle is for salvage */
-#define	WT_BTREE_SKIP_CKPT	0x040000 /* Handle skipped checkpoint */
-#define	WT_BTREE_UPGRADE	0x080000 /* Handle is for upgrade */
-#define	WT_BTREE_VERIFY		0x100000 /* Handle is for verify */
+#define	WT_BTREE_LSM_PRIMARY	0x001000 /* Handle is current LSM primary */
+#define	WT_BTREE_NO_CHECKPOINT	0x002000 /* Disable checkpoints */
+#define	WT_BTREE_NO_EVICTION	0x004000 /* Disable eviction */
+#define	WT_BTREE_NO_LOGGING	0x008000 /* Disable logging */
+#define	WT_BTREE_NO_RECONCILE	0x010000 /* Allow splits, even with no evict */
+#define	WT_BTREE_REBALANCE	0x020000 /* Handle is for rebalance */
+#define	WT_BTREE_SALVAGE	0x040000 /* Handle is for salvage */
+#define	WT_BTREE_SKIP_CKPT	0x080000 /* Handle skipped checkpoint */
+#define	WT_BTREE_UPGRADE	0x100000 /* Handle is for upgrade */
+#define	WT_BTREE_VERIFY		0x200000 /* Handle is for verify */
 	uint32_t flags;
 };
 
diff --git a/src/include/btree.i b/src/include/btree.i
index e48189d50ea..9c8ec1dbdea 100644
--- a/src/include/btree.i
+++ b/src/include/btree.i
@@ -107,7 +107,7 @@ __wt_cache_page_inmem_incr(WT_SESSION_IMPL *session, WT_PAGE *page, size_t size)
 		(void)__wt_atomic_addsize(&page->modify->bytes_dirty, size);
 		if (WT_PAGE_IS_INTERNAL(page))
 			(void)__wt_atomic_add64(&cache->bytes_dirty_intl, size);
-		else {
+		else if (!F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
 			(void)__wt_atomic_add64(&cache->bytes_dirty_leaf, size);
 			(void)__wt_atomic_add64(&btree->bytes_dirty_leaf, size);
 		}
@@ -241,7 +241,7 @@ __wt_cache_page_byte_dirty_decr(
 	if (WT_PAGE_IS_INTERNAL(page))
 		__wt_cache_decr_check_uint64(session, &cache->bytes_dirty_intl,
 		    decr, "WT_CACHE.bytes_dirty_intl");
-	else {
+	else if (!F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
 		__wt_cache_decr_check_uint64(session, &btree->bytes_dirty_leaf,
 		    decr, "WT_BTREE.bytes_dirty_leaf");
 		__wt_cache_decr_check_uint64(session, &cache->bytes_dirty_leaf,
@@ -300,8 +300,10 @@ __wt_cache_dirty_incr(WT_SESSION_IMPL *session, WT_PAGE *page)
 		(void)__wt_atomic_add64(&cache->bytes_dirty_intl, size);
 		(void)__wt_atomic_add64(&cache->pages_dirty_intl, 1);
 	} else {
-		(void)__wt_atomic_add64(&btree->bytes_dirty_leaf, size);
-		(void)__wt_atomic_add64(&cache->bytes_dirty_leaf, size);
+		if (!F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
+			(void)__wt_atomic_add64(&btree->bytes_dirty_leaf, size);
+			(void)__wt_atomic_add64(&cache->bytes_dirty_leaf, size);
+		}
 		(void)__wt_atomic_add64(&cache->pages_dirty_leaf, 1);
 	}
 	(void)__wt_atomic_addsize(&page->modify->bytes_dirty, size);
@@ -394,7 +396,7 @@ __wt_cache_page_evict(WT_SESSION_IMPL *session, WT_PAGE *page)
 			__wt_cache_decr_zero_uint64(session,
 			    &cache->bytes_dirty_intl,
 			    modify->bytes_dirty, "WT_CACHE.bytes_dirty_intl");
-		else {
+		else if (!F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
 			__wt_cache_decr_zero_uint64(session,
 			    &cache->bytes_dirty_leaf,
 			    modify->bytes_dirty, "WT_CACHE.bytes_dirty_leaf");
@@ -1543,6 +1545,57 @@ __wt_btree_lsm_over_size(WT_SESSION_IMPL *session, uint64_t maxsize)
 }
 
 /*
+ * __wt_btree_lsm_switch_primary --
+ *      Switch a btree handle to/from the current primary chunk of an LSM tree.
+ */
+static inline void
+__wt_btree_lsm_switch_primary(WT_SESSION_IMPL *session, bool on)
+{
+	WT_BTREE *btree;
+	WT_CACHE *cache;
+	WT_PAGE *child, *root;
+	WT_PAGE_INDEX *pindex;
+	WT_REF *first;
+	size_t size;
+
+	btree = S2BT(session);
+	cache = S2C(session)->cache;
+	root = btree->root.page;
+
+	if (on && !F_ISSET(btree, WT_BTREE_LSM_PRIMARY))
+		F_SET(btree, WT_BTREE_LSM_PRIMARY | WT_BTREE_NO_EVICTION);
+	if (!on && F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
+		pindex = WT_INTL_INDEX_GET_SAFE(root);
+		if (!F_ISSET(btree, WT_BTREE_NO_EVICTION) ||
+		    pindex->entries != 1)
+			return;
+		first = pindex->index[0];
+
+		/*
+		 * We're reaching down into the page without a hazard pointer,
+		 * but that's OK because we know that no-eviction is set so the
+		 * page can't disappear.
+		 */
+		child = first->page;
+		if (first->state != WT_REF_MEM ||
+		    child->type != WT_PAGE_ROW_LEAF ||
+		    !__wt_page_is_modified(child))
+			return;
+
+		/*
+		 * While this tree was the primary, its dirty bytes were not
+		 * included in the cache accounting.  Fix that now before we
+		 * open it up for eviction.
+		 */
+		size = child->modify->bytes_dirty;
+		(void)__wt_atomic_add64(&btree->bytes_dirty_leaf, size);
+		(void)__wt_atomic_add64(&cache->bytes_dirty_leaf, size);
+
+		F_CLR(btree, WT_BTREE_LSM_PRIMARY | WT_BTREE_NO_EVICTION);
+	}
+}
+
+/*
  * __wt_split_descent_race --
  *	Return if we raced with an internal page split when descending the tree.
  */
diff --git a/src/include/cursor.i b/src/include/cursor.i
index e142441e0a6..c3fcef9a13d 100644
--- a/src/include/cursor.i
+++ b/src/include/cursor.i
@@ -267,7 +267,7 @@ __cursor_func_init(WT_CURSOR_BTREE *cbt, bool reenter)
 	 * to read.
 	 */
 	if (!F_ISSET(cbt, WT_CBT_NO_TXN))
-		WT_RET(__wt_txn_cursor_op(session));
+		__wt_txn_cursor_op(session);
 	return (0);
 }
 
diff --git a/src/include/extern.h b/src/include/extern.h
index 6234f2f6bc5..ef2e9efa9fd 100644
--- a/src/include/extern.h
+++ b/src/include/extern.h
@@ -226,8 +226,10 @@ extern int __wt_config_merge(WT_SESSION_IMPL *session, const char **cfg, const c
 extern int __wt_conn_config_init(WT_SESSION_IMPL *session) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern void __wt_conn_config_discard(WT_SESSION_IMPL *session);
 extern const WT_CONFIG_ENTRY *__wt_conn_config_match(const char *method);
-extern int __wt_ext_config_parser_open(WT_EXTENSION_API *wt_ext, WT_SESSION *wt_session, const char *config, size_t len, WT_CONFIG_PARSER **config_parserp) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_ext_config_get(WT_EXTENSION_API *wt_api, WT_SESSION *wt_session, WT_CONFIG_ARG *cfg_arg, const char *key, WT_CONFIG_ITEM *cval) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern int __wt_ext_config_get_string(WT_EXTENSION_API *wt_api, WT_SESSION *wt_session, const char *config, const char *key, WT_CONFIG_ITEM *cval) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern int __wt_ext_config_parser_open(WT_EXTENSION_API *wt_ext, WT_SESSION *wt_session, const char *config, size_t len, WT_CONFIG_PARSER **config_parserp) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern int __wt_ext_config_parser_open_arg(WT_EXTENSION_API *wt_ext, WT_SESSION *wt_session, WT_CONFIG_ARG *cfg_arg, WT_CONFIG_PARSER **config_parserp) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_config_upgrade(WT_SESSION_IMPL *session, WT_ITEM *buf) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern const char *__wt_wiredtiger_error(int error);
 extern int __wt_collator_config(WT_SESSION_IMPL *session, const char *uri, WT_CONFIG_ITEM *cname, WT_CONFIG_ITEM *metadata, WT_COLLATOR **collatorp, int *ownp) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
@@ -723,7 +725,7 @@ extern int __wt_thread_group_create( WT_SESSION_IMPL *session, WT_THREAD_GROUP *
 extern int __wt_thread_group_destroy(WT_SESSION_IMPL *session, WT_THREAD_GROUP *group) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_thread_group_start_one( WT_SESSION_IMPL *session, WT_THREAD_GROUP *group, bool wait) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern void __wt_txn_release_snapshot(WT_SESSION_IMPL *session);
-extern int __wt_txn_get_snapshot(WT_SESSION_IMPL *session) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern void __wt_txn_get_snapshot(WT_SESSION_IMPL *session);
 extern int __wt_txn_update_oldest(WT_SESSION_IMPL *session, uint32_t flags) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_txn_config(WT_SESSION_IMPL *session, const char *cfg[]) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern void __wt_txn_release(WT_SESSION_IMPL *session);
diff --git a/src/include/txn.i b/src/include/txn.i
index cf7e2eafc65..0f75b2e90e1 100644
--- a/src/include/txn.i
+++ b/src/include/txn.i
@@ -262,7 +262,7 @@ __wt_txn_begin(WT_SESSION_IMPL *session, const char *cfg[])
 		 * eviction, it's better to do it beforehand.
 		 */
 		WT_RET(__wt_cache_eviction_check(session, false, NULL));
-		WT_RET(__wt_txn_get_snapshot(session));
+		__wt_txn_get_snapshot(session);
 	}
 
 	F_SET(txn, WT_TXN_RUNNING);
@@ -451,7 +451,7 @@ __wt_txn_read_last(WT_SESSION_IMPL *session)
  * __wt_txn_cursor_op --
  *	Called for each cursor operation.
  */
-static inline int
+static inline void
 __wt_txn_cursor_op(WT_SESSION_IMPL *session)
 {
 	WT_TXN *txn;
@@ -483,9 +483,7 @@ __wt_txn_cursor_op(WT_SESSION_IMPL *session)
 		if (txn_state->pinned_id == WT_TXN_NONE)
 			txn_state->pinned_id = txn_global->last_running;
 	} else if (!F_ISSET(txn, WT_TXN_HAS_SNAPSHOT))
-		WT_RET(__wt_txn_get_snapshot(session));
-
-	return (0);
+		__wt_txn_get_snapshot(session);
 }
 
 /*
diff --git a/src/include/wiredtiger.in b/src/include/wiredtiger.in
index 665e8eaf4b0..8da46582924 100644
--- a/src/include/wiredtiger.in
+++ b/src/include/wiredtiger.in
@@ -827,6 +827,11 @@ struct __wt_session {
 	 *
 	 * @param session the session handle
 	 * @configstart{WT_SESSION.reconfigure, see dist/api_data.py}
+	 * @config{ignore_cache_size, when set\, operations performed by this
+	 * session ignore the cache size and are not blocked when the cache is
+	 * full.  Note that use of this option for operations that create cache
+	 * pressure can starve ordinary sessions that obey the cache size., a
+	 * boolean flag; default \c false.}
 	 * @config{isolation, the default isolation level for operations in this
 	 * session., a string\, chosen from the following options: \c
 	 * "read-uncommitted"\, \c "read-committed"\, \c "snapshot"; default \c
@@ -2005,6 +2010,11 @@ struct __wt_connection {
 	 * connection's error handler is used. See @ref error_handling_event
 	 * for more information.
 	 * @configstart{WT_CONNECTION.open_session, see dist/api_data.py}
+	 * @config{ignore_cache_size, when set\, operations performed by this
+	 * session ignore the cache size and are not blocked when the cache is
+	 * full.  Note that use of this option for operations that create cache
+	 * pressure can starve ordinary sessions that obey the cache size., a
+	 * boolean flag; default \c false.}
 	 * @config{isolation, the default isolation level for operations in this
 	 * session., a string\, chosen from the following options: \c
 	 * "read-uncommitted"\, \c "read-committed"\, \c "snapshot"; default \c
@@ -2204,6 +2214,11 @@ struct __wt_connection {
  * I/O. The default value of -1 indicates a platform-specific alignment value
  * should be used (4KB on Linux systems when direct I/O is configured\, zero
  * elsewhere)., an integer between -1 and 1MB; default \c -1.}
+ * @config{builtin_extension_config, A structure where the keys are the names of
+ * builtin extensions and the values are passed to WT_CONNECTION::load_extension
+ * as the \c config parameter (for example\,
+ * <code>builtin_extension_config={zlib={compression_level=3}}</code>)., a
+ * string; default empty.}
  * @config{cache_overhead, assume the heap allocator overhead is the specified
  * percentage\, and adjust the cache usage by that amount (for example\, if
  * there is 10GB of data in cache\, a percentage of 10 means WiredTiger treats
diff --git a/src/include/wiredtiger_ext.h b/src/include/wiredtiger_ext.h
index 3d65cd1fc24..236d4e07e67 100644
--- a/src/include/wiredtiger_ext.h
+++ b/src/include/wiredtiger_ext.h
@@ -204,25 +204,47 @@ struct __wt_extension_api {
 	    WT_COLLATOR *collator, WT_ITEM *first, WT_ITEM *second, int *cmp);
 
 	/*!
-	 * @copydoc wiredtiger_config_parser_open
+	 * Return the value of a configuration key.
+	 *
+	 * @param wt_api the extension handle
+	 * @param session the session handle (or NULL if none available)
+	 * @param config the configuration information passed to an application
+	 * @param key configuration key string
+	 * @param value the returned value
+	 * @errors
+	 *
+	 * @snippet ex_data_source.c WT_EXTENSION config_get
 	 */
-	int (*config_parser_open)(WT_EXTENSION_API *wt_api, WT_SESSION *session,
-	    const char *config, size_t len, WT_CONFIG_PARSER **config_parserp);
+	int (*config_get)(WT_EXTENSION_API *wt_api, WT_SESSION *session,
+	    WT_CONFIG_ARG *config, const char *key, WT_CONFIG_ITEM *value);
 
 	/*!
-	 * Return the value of a configuration string.
+	 * Return the value of a configuration key from a string.
 	 *
 	 * @param wt_api the extension handle
 	 * @param session the session handle (or NULL if none available)
+	 * @param config the configuration string
 	 * @param key configuration key string
-	 * @param config the configuration information passed to an application
 	 * @param value the returned value
 	 * @errors
 	 *
 	 * @snippet ex_data_source.c WT_EXTENSION config_get
 	 */
-	int (*config_get)(WT_EXTENSION_API *wt_api, WT_SESSION *session,
-	    WT_CONFIG_ARG *config, const char *key, WT_CONFIG_ITEM *value);
+	int (*config_get_string)(WT_EXTENSION_API *wt_api, WT_SESSION *session,
+	    const char *config, const char *key, WT_CONFIG_ITEM *value);
+
+	/*!
+	 * @copydoc wiredtiger_config_parser_open
+	 */
+	int (*config_parser_open)(WT_EXTENSION_API *wt_api, WT_SESSION *session,
+	    const char *config, size_t len, WT_CONFIG_PARSER **config_parserp);
+
+	/*!
+	 * @copydoc wiredtiger_config_parser_open
+	 */
+	int (*config_parser_open_arg)(WT_EXTENSION_API *wt_api,
+	    WT_SESSION *session, WT_CONFIG_ARG *config,
+	    WT_CONFIG_PARSER **config_parserp);
 
 	/*!
 	 * Insert a row into the metadata if it does not already exist.
diff --git a/src/log/log.c b/src/log/log.c
index 00e4ea5f441..8b6c8b2c490 100644
--- a/src/log/log.c
+++ b/src/log/log.c
@@ -21,6 +21,60 @@ static int __log_write_internal(
 #define	WT_LOG_OPEN_VERIFY	0x02
 
 /*
+ * __log_wait_for_earlier_slot --
+ *	Wait for write_lsn to catch up to this slot.
+ */
+static void
+__log_wait_for_earlier_slot(WT_SESSION_IMPL *session, WT_LOGSLOT *slot)
+{
+	WT_CONNECTION_IMPL *conn;
+	WT_LOG *log;
+	int yield_count;
+
+	conn = S2C(session);
+	log = conn->log;
+	yield_count = 0;
+
+	while (__wt_log_cmp(&log->write_lsn, &slot->slot_release_lsn) != 0) {
+		/*
+		 * If we're on a locked path and the write LSN is not advancing,
+		 * unlock in case an earlier thread is trying to switch its
+		 * slot and complete its operation.
+		 */
+		if (F_ISSET(session, WT_SESSION_LOCKED_SLOT))
+			__wt_spin_unlock(session, &log->log_slot_lock);
+		__wt_cond_auto_signal(session, conn->log_wrlsn_cond);
+		if (++yield_count < WT_THOUSAND)
+			__wt_yield();
+		else
+			__wt_cond_wait(session, log->log_write_cond, 200);
+		if (F_ISSET(session, WT_SESSION_LOCKED_SLOT))
+			__wt_spin_lock(session, &log->log_slot_lock);
+	}
+}
+
+/*
+ * __log_fs_write --
+ *	Wrapper when writing to a log file.  If we're writing to a new log
+ *	file for the first time wait for writes to the previous log file.
+ */
+static int
+__log_fs_write(WT_SESSION_IMPL *session,
+    WT_LOGSLOT *slot, wt_off_t offset, size_t len, const void *buf)
+{
+	/*
+	 * If we're writing into a new log file, we have to wait for all
+	 * writes to the previous log file to complete otherwise there could
+	 * be a hole at the end of the previous log file that we cannot detect.
+	 */
+	if (slot->slot_release_lsn.l.file < slot->slot_start_lsn.l.file) {
+		__log_wait_for_earlier_slot(session, slot);
+		WT_RET(__wt_log_force_sync(session, &slot->slot_release_lsn));
+	}
+	return (__wt_write(session, slot->slot_fh, offset, len, buf));
+}
+
+/*
  * __wt_log_ckpt --
  *	Record the given LSN as the checkpoint LSN and signal the archive
  *	thread as needed.
@@ -371,8 +425,6 @@ __wt_log_extract_lognum(
 {
 	const char *p;
 
-	WT_UNUSED(session);
-
 	if (id == NULL || name == NULL)
 		return (WT_ERROR);
 	if ((p = strrchr(name, '.')) == NULL ||
@@ -576,7 +628,7 @@ __log_fill(WT_SESSION_IMPL *session,
 		/*
 		 * If this is a force or unbuffered write, write it now.
 		 */
-		WT_ERR(__wt_write(session, myslot->slot->slot_fh,
+		WT_ERR(__log_fs_write(session, myslot->slot,
 		    myslot->offset + myslot->slot->slot_start_offset,
 		    record->size, record->mem));
 
@@ -1352,13 +1404,11 @@ __wt_log_release(WT_SESSION_IMPL *session, WT_LOGSLOT *slot, bool *freep)
 	WT_LSN sync_lsn;
 	int64_t release_buffered, release_bytes;
 	uint64_t fsync_duration_usecs;
-	int yield_count;
 	bool locked;
 
 	conn = S2C(session);
 	log = conn->log;
 	locked = false;
-	yield_count = 0;
 	if (freep != NULL)
 		*freep = 1;
 	release_buffered = WT_LOG_SLOT_RELEASED_BUFFERED(slot->slot_state);
@@ -1379,8 +1429,7 @@ __wt_log_release(WT_SESSION_IMPL *session, WT_LOGSLOT *slot, bool *freep)
 
 	/* Write the buffered records */
 	if (release_buffered != 0)
-		WT_ERR(__wt_write(session,
-		    slot->slot_fh, slot->slot_start_offset,
+		WT_ERR(__log_fs_write(session, slot, slot->slot_start_offset,
 		    (size_t)release_buffered, slot->slot_buf.mem));
 
 	/*
@@ -1411,22 +1460,7 @@ __wt_log_release(WT_SESSION_IMPL *session, WT_LOGSLOT *slot, bool *freep)
 	 * be holes in the log file.
 	 */
 	WT_STAT_CONN_INCR(session, log_release_write_lsn);
-	while (__wt_log_cmp(&log->write_lsn, &slot->slot_release_lsn) != 0) {
-		/*
-		 * If we're on a locked path and the write LSN is not advancing,
-		 * unlock in case an earlier thread is trying to switch its
-		 * slot and complete its operation.
-		 */
-		if (F_ISSET(session, WT_SESSION_LOCKED_SLOT))
-			__wt_spin_unlock(session, &log->log_slot_lock);
-		__wt_cond_auto_signal(session, conn->log_wrlsn_cond);
-		if (++yield_count < WT_THOUSAND)
-			__wt_yield();
-		else
-			__wt_cond_wait(session, log->log_write_cond, 200);
-		if (F_ISSET(session, WT_SESSION_LOCKED_SLOT))
-			__wt_spin_lock(session, &log->log_slot_lock);
-	}
+	__log_wait_for_earlier_slot(session, slot);
 
 	log->write_start_lsn = slot->slot_start_lsn;
 	log->write_lsn = slot->slot_end_lsn;
diff --git a/src/lsm/lsm_cursor.c b/src/lsm/lsm_cursor.c
index c20673563d9..c40f0f64b33 100644
--- a/src/lsm/lsm_cursor.c
+++ b/src/lsm/lsm_cursor.c
@@ -215,7 +215,7 @@ __clsm_enter(WT_CURSOR_LSM *clsm, bool reset, bool update)
 				goto open;
 
 			if (txn->isolation == WT_ISO_SNAPSHOT)
-				WT_RET(__wt_txn_cursor_op(session));
+				__wt_txn_cursor_op(session);
 
 			/*
 			 * Figure out how many updates are required for
@@ -700,7 +700,7 @@ retry:	if (F_ISSET(clsm, WT_CLSM_MERGE)) {
 		if (btree->bulk_load_ok) {
 			btree->bulk_load_ok = false;
 			WT_WITH_BTREE(session, btree,
-			    __wt_btree_evictable(session, false));
+			    __wt_btree_lsm_switch_primary(session, true));
 		}
 	}
 
diff --git a/src/lsm/lsm_work_unit.c b/src/lsm/lsm_work_unit.c
index 917104031fc..dfb8690f1ed 100644
--- a/src/lsm/lsm_work_unit.c
+++ b/src/lsm/lsm_work_unit.c
@@ -383,7 +383,7 @@ __wt_lsm_checkpoint_chunk(WT_SESSION_IMPL *session,
 	 * forced eviction.
 	 */
 	WT_ERR(__wt_session_get_btree(session, chunk->uri, NULL, NULL, 0));
-	__wt_btree_evictable(session, true);
+	__wt_btree_lsm_switch_primary(session, false);
 	WT_ERR(__wt_session_release_btree(session));
 
 	/* Make sure we aren't pinning a transaction ID. */
diff --git a/src/os_common/os_fs_inmemory.c b/src/os_common/os_fs_inmemory.c
index 70a82007300..1670e97be45 100644
--- a/src/os_common/os_fs_inmemory.c
+++ b/src/os_common/os_fs_inmemory.c
@@ -515,8 +515,6 @@ __im_terminate(WT_FILE_SYSTEM *file_system, WT_SESSION *wt_session)
 	WT_FILE_SYSTEM_INMEM *im_fs;
 	WT_SESSION_IMPL *session;
 
-	WT_UNUSED(file_system);
-
 	session = (WT_SESSION_IMPL *)wt_session;
 	im_fs = (WT_FILE_SYSTEM_INMEM *)file_system;
 
diff --git a/src/os_posix/os_dir.c b/src/os_posix/os_dir.c
index 768a1324cd8..627278540d1 100644
--- a/src/os_posix/os_dir.c
+++ b/src/os_posix/os_dir.c
@@ -28,8 +28,6 @@ __wt_posix_directory_list(WT_FILE_SYSTEM *file_system,
 	int tret;
 	char **entries;
 
-	WT_UNUSED(file_system);
-
 	session = (WT_SESSION_IMPL *)wt_session;
 
 	*dirlistp = NULL;
diff --git a/src/os_posix/os_fs.c b/src/os_posix/os_fs.c
index c6272b5da52..5f06892ce6e 100644
--- a/src/os_posix/os_fs.c
+++ b/src/os_posix/os_fs.c
@@ -746,8 +746,6 @@ __posix_terminate(WT_FILE_SYSTEM *file_system, WT_SESSION *wt_session)
 {
 	WT_SESSION_IMPL *session;
 
-	WT_UNUSED(file_system);
-
 	session = (WT_SESSION_IMPL *)wt_session;
 
 	__wt_free(session, file_system);
diff --git a/src/os_win/os_dir.c b/src/os_win/os_dir.c
index f024d131387..47d4f95b793 100644
--- a/src/os_win/os_dir.c
+++ b/src/os_win/os_dir.c
@@ -30,8 +30,6 @@ __wt_win_directory_list(WT_FILE_SYSTEM *file_system,
 	uint32_t count;
 	char *dir_copy, **entries;
 
-	WT_UNUSED(file_system);
-
 	session = (WT_SESSION_IMPL *)wt_session;
 
 	*dirlistp = NULL;
diff --git a/src/session/session_api.c b/src/session/session_api.c
index 3afea383b08..00c2852649f 100644
--- a/src/session/session_api.c
+++ b/src/session/session_api.c
@@ -249,18 +249,36 @@ __session_reconfigure(WT_SESSION *wt_session, const char *config)
 	session = (WT_SESSION_IMPL *)wt_session;
 	SESSION_API_CALL(session, reconfigure, config, cfg);
 
+	/*
+	 * Note that this method only checks keys that are passed in by the
+	 * application: we don't want to reset other session settings to their
+	 * default values.
+	 */
+	WT_UNUSED(cfg);
+
 	if (F_ISSET(&session->txn, WT_TXN_RUNNING))
 		WT_ERR_MSG(session, EINVAL, "transaction in progress");
 
-	WT_TRET(__wt_session_reset_cursors(session, false));
+	WT_ERR(__wt_session_reset_cursors(session, false));
 
-	WT_ERR(__wt_config_gets_def(session, cfg, "isolation", 0, &cval));
-	if (cval.len != 0)
+	ret = __wt_config_getones(session, config, "isolation", &cval);
+	if (ret == 0 && cval.len != 0) {
 		session->isolation = session->txn.isolation =
 		    WT_STRING_MATCH("snapshot", cval.str, cval.len) ?
 		    WT_ISO_SNAPSHOT :
 		    WT_STRING_MATCH("read-uncommitted", cval.str, cval.len) ?
 		    WT_ISO_READ_UNCOMMITTED : WT_ISO_READ_COMMITTED;
+	}
+	WT_ERR_NOTFOUND_OK(ret);
+
+	ret = __wt_config_getones(session, config, "ignore_cache_size", &cval);
+	if (ret == 0) {
+		if (cval.val)
+			F_SET(session, WT_SESSION_NO_EVICTION);
+		else
+			F_CLR(session, WT_SESSION_NO_EVICTION);
+	}
+	WT_ERR_NOTFOUND_OK(ret);
 
 err:	API_END_RET_NOTFOUND_MAP(session, ret);
 }
diff --git a/src/support/hazard.c b/src/support/hazard.c
index b1978dbe97a..27508bbdece 100644
--- a/src/support/hazard.c
+++ b/src/support/hazard.c
@@ -26,6 +26,7 @@ __wt_hazard_set(WT_SESSION_IMPL *session, WT_REF *ref, bool *busyp
 	WT_BTREE *btree;
 	WT_CONNECTION_IMPL *conn;
 	WT_HAZARD *hp;
+	WT_PAGE *page;
 	int restarts = 0;
 
 	btree = S2BT(session);
@@ -37,6 +38,16 @@ __wt_hazard_set(WT_SESSION_IMPL *session, WT_REF *ref, bool *busyp
 		return (0);
 
 	/*
+	 * If there isn't a valid page pointer, we're done.  This read can race
+	 * with eviction and splits, we re-check it after a barrier to make
+	 * sure we have a valid pointer.
+	 */
+	if (ref->state != WT_REF_MEM || (page = ref->page) == NULL) {
+		*busyp = true;
+		return (0);
+	}
+
+	/*
 	 * Do the dance:
 	 *
 	 * The memory location which makes a page "real" is the WT_REF's state
@@ -82,7 +93,7 @@ __wt_hazard_set(WT_SESSION_IMPL *session, WT_REF *ref, bool *busyp
 		if (hp->page != NULL)
 			continue;
 
-		hp->page = ref->page;
+		hp->page = page;
 #ifdef HAVE_DIAGNOSTIC
 		hp->file = file;
 		hp->line = line;
@@ -101,9 +112,12 @@ __wt_hazard_set(WT_SESSION_IMPL *session, WT_REF *ref, bool *busyp
 		 * found this page using the tree's key space, whatever page we
 		 * find here is the page for us to use.)
 		 */
-		if (ref->page == hp->page && ref->state == WT_REF_MEM) {
-			++session->nhazard;
-			return (0);
+		if (ref->state == WT_REF_MEM) {
+			WT_READ_BARRIER();
+			if (ref->page == page) {
+				++session->nhazard;
+				return (0);
+			}
 		}
 
 		/*
diff --git a/src/txn/txn.c b/src/txn/txn.c
index 1c47f94bb60..3dba51f5220 100644
--- a/src/txn/txn.c
+++ b/src/txn/txn.c
@@ -108,7 +108,7 @@ __wt_txn_release_snapshot(WT_SESSION_IMPL *session)
  * __wt_txn_get_snapshot --
  *	Allocate a snapshot.
  */
-int
+void
 __wt_txn_get_snapshot(WT_SESSION_IMPL *session)
 {
 	WT_CONNECTION_IMPL *conn;
@@ -180,7 +180,6 @@ __wt_txn_get_snapshot(WT_SESSION_IMPL *session)
 
 done:	__wt_readunlock(session, txn_global->scan_rwlock);
 	__txn_sort_snapshot(session, n, current_id);
-	return (0);
 }
 
 /*
diff --git a/src/txn/txn_ckpt.c b/src/txn/txn_ckpt.c
index 1efd0200a3d..8fc7bc821b0 100644
--- a/src/txn/txn_ckpt.c
+++ b/src/txn/txn_ckpt.c
@@ -242,8 +242,6 @@ __wt_checkpoint_get_handles(WT_SESSION_IMPL *session, const char *cfg[])
 	WT_DECL_RET;
 	const char *name;
 
-	WT_UNUSED(cfg);
-
 	/* Should not be called with anything other than a file object. */
 	WT_ASSERT(session, session->dhandle->checkpoint == NULL);
 	WT_ASSERT(session, WT_PREFIX_MATCH(session->dhandle->name, "file:"));
diff --git a/src/txn/txn_recover.c b/src/txn/txn_recover.c
index 65811aa3bf4..a6390dcbd06 100644
--- a/src/txn/txn_recover.c
+++ b/src/txn/txn_recover.c
@@ -248,8 +248,6 @@ static int
 __txn_commit_apply(
     WT_RECOVERY *r, WT_LSN *lsnp, const uint8_t **pp, const uint8_t *end)
 {
-	WT_UNUSED(lsnp);
-
 	/* The logging subsystem zero-pads records. */
 	while (*pp < end && **pp)
 		WT_RET(__txn_op_apply(r, lsnp, pp, end));
diff --git a/test/format/config.c b/test/format/config.c
index 839ff5058de..cf922b5db04 100644
--- a/test/format/config.c
+++ b/test/format/config.c
@@ -301,7 +301,7 @@ config_compression(const char *conf_name)
 		break;
 #endif
 #ifdef HAVE_BUILTIN_EXTENSION_ZSTD
-	case 15: case 16 case 17:		/* 15% zstd */
+	case 15: case 16: case 17:		/* 15% zstd */
 		cstr = "zstd";
 		break;
 #endif
diff --git a/test/recovery/random-abort.c b/test/recovery/random-abort.c
index 03e67e2f723..c407361c7eb 100644
--- a/test/recovery/random-abort.c
+++ b/test/recovery/random-abort.c
@@ -34,6 +34,7 @@
 static char home[512];			/* Program working dir */
 static const char *progname;		/* Program name */
 static const char * const uri = "table:main";
+static bool inmem;
 
 #define	MAX_TH	12
 #define	MIN_TH	5
@@ -41,7 +42,9 @@ static const char * const uri = "table:main";
 #define	MIN_TIME	10
 #define	RECORDS_FILE	"records-%" PRIu32
 
-#define	ENV_CONFIG						\
+#define	ENV_CONFIG_DEF						\
+    "create,log=(file_max=10M,archive=false,enabled)"
+#define	ENV_CONFIG_TXNSYNC					\
     "create,log=(file_max=10M,archive=false,enabled),"		\
     "transaction_sync=(enabled,method=none)"
 #define	ENV_CONFIG_REC "log=(recover=on)"
@@ -73,11 +76,15 @@ thread_run(void *arg)
 	WT_THREAD_DATA *td;
 	uint64_t i;
 	int ret;
-	char buf[MAX_VAL], kname[64];
+	size_t lsize;
+	char buf[MAX_VAL], kname[64], lgbuf[8];
+	char large[128*1024];
 
 	__wt_random_init(&rnd);
 	memset(buf, 0, sizeof(buf));
 	memset(kname, 0, sizeof(kname));
+	lsize = sizeof(large);
+	memset(large, 0, lsize);
 
 	td = (WT_THREAD_DATA *)arg;
 	/*
@@ -85,6 +92,13 @@ thread_run(void *arg)
 	 */
 	snprintf(buf, sizeof(buf), RECORDS_FILE, td->id);
 	/*
+	 * Set up a large value putting our id in it.  Write it in there a
+	 * bunch of times, but the rest of the buffer can just be zero.
+	 */
+	snprintf(lgbuf, sizeof(lgbuf), "th-%" PRIu32, td->id);
+	for (i = 0; i < 128; i += strlen(lgbuf))
+		snprintf(&large[i], lsize - i, "%s", lgbuf);
+	/*
 	 * Keep a separate file with the records we wrote for checking.
 	 */
 	(void)unlink(buf);
@@ -107,8 +121,18 @@ thread_run(void *arg)
 	 */
 	for (i = td->start; ; ++i) {
 		snprintf(kname, sizeof(kname), "%" PRIu64, i);
-		data.size = __wt_random(&rnd) % MAX_VAL;
 		cursor->set_key(cursor, kname);
+		/*
+		 * Every 30th record write a very large record that exceeds the
+		 * log buffer size.  This forces us to use the unbuffered path.
+		 */
+		if (i % 30 == 0) {
+			data.size = 128 * 1024;
+			data.data = large;
+		} else {
+			data.size = __wt_random(&rnd) % MAX_VAL;
+			data.data = buf;
+		}
 		cursor->set_value(cursor, &data);
 		if ((ret = cursor->insert(cursor)) != 0)
 			testutil_die(ret, "WT_CURSOR.insert");
@@ -136,12 +160,17 @@ fill_db(uint32_t nth)
 	WT_THREAD_DATA *td;
 	uint32_t i;
 	int ret;
+	const char *envconf;
 
 	thr = dcalloc(nth, sizeof(pthread_t));
 	td = dcalloc(nth, sizeof(WT_THREAD_DATA));
 	if (chdir(home) != 0)
 		testutil_die(errno, "Child chdir: %s", home);
-	if ((ret = wiredtiger_open(NULL, NULL, ENV_CONFIG, &conn)) != 0)
+	if (inmem)
+		envconf = ENV_CONFIG_DEF;
+	else
+		envconf = ENV_CONFIG_TXNSYNC;
+	if ((ret = wiredtiger_open(NULL, NULL, envconf, &conn)) != 0)
 		testutil_die(ret, "wiredtiger_open");
 	if ((ret = conn->open_session(conn, NULL, NULL, &session)) != 0)
 		testutil_die(ret, "WT_CONNECTION:open_session");
@@ -187,11 +216,11 @@ main(int argc, char *argv[])
 	WT_CURSOR *cursor;
 	WT_SESSION *session;
 	WT_RAND_STATE rnd;
-	uint64_t key, last_key;
-	uint32_t absent, count, i, nth, timeout;
+	uint64_t absent, count, key, last_key, middle;
+	uint32_t i, nth, timeout;
 	int ch, status, ret;
 	pid_t pid;
-	bool rand_th, rand_time, verify_only;
+	bool fatal, rand_th, rand_time, verify_only;
 	const char *working_dir;
 	char fname[64], kname[64];
 
@@ -200,17 +229,21 @@ main(int argc, char *argv[])
 	else
 		++progname;
 
+	inmem = false;
 	nth = MIN_TH;
 	rand_th = rand_time = true;
 	timeout = MIN_TIME;
 	verify_only = false;
 	working_dir = "WT_TEST.random-abort";
 
-	while ((ch = __wt_getopt(progname, argc, argv, "h:T:t:v")) != EOF)
+	while ((ch = __wt_getopt(progname, argc, argv, "h:mT:t:v")) != EOF)
 		switch (ch) {
 		case 'h':
 			working_dir = __wt_optarg;
 			break;
+		case 'm':
+			inmem = true;
+			break;
 		case 'T':
 			rand_th = false;
 			nth = (uint32_t)atoi(__wt_optarg);
@@ -303,7 +336,9 @@ main(int argc, char *argv[])
 		testutil_die(ret, "WT_SESSION.open_cursor: %s", uri);
 
 	absent = count = 0;
+	fatal = false;
 	for (i = 0; i < nth; ++i) {
+		middle = 0;
 		snprintf(fname, sizeof(fname), RECORDS_FILE, i);
 		if ((fp = fopen(fname, "r")) == NULL) {
 			fprintf(stderr,
@@ -313,8 +348,10 @@ main(int argc, char *argv[])
 
 		/*
 		 * For every key in the saved file, verify that the key exists
-		 * in the table after recovery.  Since we did write-no-sync, we
-		 * expect every key to have been recovered.
+		 * in the table after recovery.  If we're doing in-memory
+		 * log buffering we never expect a record missing in the middle,
+		 * but records may be missing at the end.  If we did
+		 * write-no-sync, we expect every key to have been recovered.
 		 */
 		for (last_key = UINT64_MAX;; ++count, last_key = key) {
 			ret = fscanf(fp, "%" SCNu64 "\n", &key);
@@ -338,9 +375,20 @@ main(int argc, char *argv[])
 			if ((ret = cursor->search(cursor)) != 0) {
 				if (ret != WT_NOTFOUND)
 					testutil_die(ret, "search");
-				printf("%s: no record with key %" PRIu64 "\n",
-				    fname, key);
-				++absent;
+				if (!inmem)
+					printf("%s: no record with key %"
+					    PRIu64 "\n", fname, key);
+				absent++;
+				middle = key;
+			} else if (middle != 0) {
+				/*
+				 * We should never find an existing key after
+				 * we have detected one missing.
+				 */
+				printf("%s: after absent record at %" PRIu64
+				    " key %" PRIu64 " exists\n",
+				    fname, middle, key);
+				fatal = true;
 			}
 		}
 		if (fclose(fp) != 0)
@@ -348,11 +396,13 @@ main(int argc, char *argv[])
 	}
 	if ((ret = conn->close(conn, NULL)) != 0)
 		testutil_die(ret, "WT_CONNECTION:close");
-	if (absent) {
-		printf("%" PRIu32 " record(s) absent from %" PRIu32 "\n",
+	if (fatal)
+		return (EXIT_FAILURE);
+	if (!inmem && absent) {
+		printf("%" PRIu64 " record(s) absent from %" PRIu64 "\n",
 		    absent, count);
 		return (EXIT_FAILURE);
 	}
-	printf("%" PRIu32 " records verified\n", count);
+	printf("%" PRIu64 " records verified\n", count);
 	return (EXIT_SUCCESS);
 }
diff --git a/test/recovery/smoke.sh b/test/recovery/smoke.sh
index c7677b64503..ce0662d3b2b 100755
--- a/test/recovery/smoke.sh
+++ b/test/recovery/smoke.sh
@@ -5,4 +5,5 @@ set -e
 # Smoke-test recovery as part of running "make check".
 
 $TEST_WRAPPER ./random-abort -t 10 -T 5
+$TEST_WRAPPER ./random-abort -m -t 10 -T 5
 $TEST_WRAPPER ./truncated-log
diff --git a/test/suite/test_compact02.py b/test/suite/test_compact02.py
index fe31aa1cbe1..3a4ca6cbc7e 100644
--- a/test/suite/test_compact02.py
+++ b/test/suite/test_compact02.py
@@ -80,8 +80,11 @@ class test_compact02(wttest.WiredTigerTestCase):
 
     # Return the size of the file
     def getSize(self):
+        # To allow this to work on systems without ftruncate,
+        # get the portion of the file allocated, via 'statistics=(all)',
+        # not the physical file size, via 'statistics=(size)'.
         cstat = self.session.open_cursor(
-            'statistics:' + self.uri, None, 'statistics=(size)')
+            'statistics:' + self.uri, None, 'statistics=(all)')
         sz = cstat[stat.dsrc.block_size][2]
         cstat.close()
         return sz
@@ -96,7 +99,7 @@ class test_compact02(wttest.WiredTigerTestCase):
         self.home = '.'
         conn_params = 'create,' + \
             cacheSize + ',error_prefix="%s: ",' % self.shortid() + \
-            'statistics=(fast),eviction_dirty_target=99,eviction_dirty_trigger=99'
+            'statistics=(all),eviction_dirty_target=99,eviction_dirty_trigger=99'
         try:
             self.conn = wiredtiger.wiredtiger_open(self.home, conn_params)
         except wiredtiger.WiredTigerError as e:
diff --git a/test/suite/test_reconfig04.py b/test/suite/test_reconfig04.py
new file mode 100644
index 00000000000..be5e6d3729e
--- /dev/null
+++ b/test/suite/test_reconfig04.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+#
+# Public Domain 2014-2016 MongoDB, Inc.
+# Public Domain 2008-2014 WiredTiger, Inc.
+#
+# This is free and unencumbered software released into the public domain.
+#
+# Anyone is free to copy, modify, publish, use, compile, sell, or
+# distribute this software, either in source code form or as a compiled
+# binary, for any purpose, commercial or non-commercial, and by any
+# means.
+#
+# In jurisdictions that recognize copyright laws, the author or authors
+# of this software dedicate any and all copyright interest in the
+# software to the public domain. We make this dedication for the benefit
+# of the public at large and to the detriment of our heirs and
+# successors. We intend this dedication to be an overt act of
+# relinquishment in perpetuity of all present and future rights to this
+# software under copyright law.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+
+import fnmatch, os, time
+import wiredtiger, wttest
+from wtdataset import SimpleDataSet
+
+# test_reconfig04.py
+#    Test WT_SESSION::reconfigure
+class test_reconfig04(wttest.WiredTigerTestCase):
+    def test_session_reconfigure(self):
+        self.session.reconfigure('ignore_cache_size=false')
+
+        self.session.reconfigure('isolation=snapshot')
+        self.session.reconfigure('isolation=read-committed')
+        self.session.reconfigure('isolation=read-uncommitted')
+
+        self.session.reconfigure('ignore_cache_size=true')
+        self.session.reconfigure('isolation=snapshot')
+
+if __name__ == '__main__':
+    wttest.run()