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.

1 files changed, 8 insertions, 3 deletions

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']),