WT-3002 Allow applications to exempt threads from eviction. (#3116)

* WT-3002 Allow applications to exempt threads from eviction.

* Update wiredtiger.in.

* Rename config key, make WT_SESSION::reconfigure only apply to passed-in values.

Add a basic smoke test of WT_SESSION::reconfigure.

* whitespace

* Update.

6 files changed, 97 insertions, 13 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..7016be374a8 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']),
diff --git a/src/config/config_def.c b/src/config/config_def.c
index d57bc418c93..540cf846e90 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\"]",
@@ -1017,8 +1019,8 @@ 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 +1118,8 @@ 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",
 	  "",
diff --git a/src/include/wiredtiger.in b/src/include/wiredtiger.in
index 665e8eaf4b0..296e510d8d4 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
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/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()