Add configuration for dbengine page fetch timeout and retry count (#13194)

* Add configuration for page cache fetch timeout and retry count
Change page cache wait default timeout to 3 seconds

* Issue info message in the error.log if values not within expected lower range

* Fix compilation errors with --disable-dbengine

5 files changed, 23 insertions, 4 deletions

diff --git a/daemon/main.c b/daemon/main.c
index 6a07add1c9..35f2c189e4 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -1231,6 +1231,20 @@ int main(int argc, char **argv) {
         // initialize the log files
         open_all_log_files();
 
+#ifdef ENABLE_DBENGINE
+        default_rrdeng_page_fetch_timeout = (int) config_get_number(CONFIG_SECTION_GLOBAL, "dbengine page fetch timeout", PAGE_CACHE_FETCH_WAIT_TIMEOUT);
+        if (default_rrdeng_page_fetch_timeout < 1) {
+            info("\"dbengine page fetch timeout\" found in netdata.conf cannot be %d, using 1", default_rrdeng_page_fetch_timeout);
+            default_rrdeng_page_fetch_timeout = 1;
+        }
+
+        default_rrdeng_page_fetch_retries = (int) config_get_number(CONFIG_SECTION_GLOBAL, "dbengine page fetch retries", MAX_PAGE_CACHE_FETCH_RETRIES);
+        if (default_rrdeng_page_fetch_retries < 1) {
+            info("\"dbengine page fetch retries\" found in netdata.conf cannot be %d, using 1", default_rrdeng_page_fetch_retries);
+            default_rrdeng_page_fetch_retries = 1;
+        }
+#endif
+
         get_system_timezone();
         // --------------------------------------------------------------------
         // get the certificate and start security
diff --git a/database/engine/pagecache.c b/database/engine/pagecache.c
index 5c56df72ab..9a5891d41e 100644
--- a/database/engine/pagecache.c
+++ b/database/engine/pagecache.c
@@ -1067,9 +1067,9 @@ pg_cache_lookup_next(struct rrdengine_instance *ctx, struct pg_cache_page_index
     int retry_count = 0;
     while (1) {
         descr = find_first_page_in_time_range(page_index, start_time, end_time);
-        if (NULL == descr || 0 == descr->page_length || retry_count == MAX_PAGE_CACHE_RETRY_WAIT) {
+        if (NULL == descr || 0 == descr->page_length || retry_count == default_rrdeng_page_fetch_retries) {
             /* non-empty page not found */
-            if (retry_count == MAX_PAGE_CACHE_RETRY_WAIT)
+            if (retry_count == default_rrdeng_page_fetch_retries)
                 error_report("Page cache timeout while waiting for page %p : returning FAIL", descr);
             uv_rwlock_rdunlock(&page_index->lock);
 
@@ -1115,7 +1115,7 @@ pg_cache_lookup_next(struct rrdengine_instance *ctx, struct pg_cache_page_index
         if (!(flags & RRD_PAGE_POPULATED))
             page_not_in_cache = 1;
 
-        if (pg_cache_timedwait_event_unsafe(descr, 1) == UV_ETIMEDOUT) {
+        if (pg_cache_timedwait_event_unsafe(descr, default_rrdeng_page_fetch_timeout) == UV_ETIMEDOUT) {
             error_report("Page cache timeout while waiting for page %p : retry count = %d", descr, retry_count);
             ++retry_count;
         }
diff --git a/database/engine/pagecache.h b/database/engine/pagecache.h
index 0ba4639cec..6c157dfba2 100644
--- a/database/engine/pagecache.h
+++ b/database/engine/pagecache.h
@@ -11,7 +11,8 @@ struct extent_info;
 struct rrdeng_page_descr;
 
 #define INVALID_TIME (0)
-#define MAX_PAGE_CACHE_RETRY_WAIT (3)
+#define MAX_PAGE_CACHE_FETCH_RETRIES (3)
+#define PAGE_CACHE_FETCH_WAIT_TIMEOUT (3)
 
 /* Page flags */
 #define RRD_PAGE_DIRTY          (1LU << 0)
diff --git a/database/engine/rrdengineapi.c b/database/engine/rrdengineapi.c
index 0792ebe001..180623ca02 100755
--- a/database/engine/rrdengineapi.c
+++ b/database/engine/rrdengineapi.c
@@ -5,6 +5,8 @@
 struct rrdengine_instance multidb_ctx;
 
 int db_engine_use_malloc = 0;
+int default_rrdeng_page_fetch_timeout = 3;
+int default_rrdeng_page_fetch_retries = 3;
 int default_rrdeng_page_cache_mb = 32;
 int default_rrdeng_disk_quota_mb = 256;
 int default_multidb_disk_quota_mb = 256;
diff --git a/database/engine/rrdengineapi.h b/database/engine/rrdengineapi.h
index 798545d9d7..7073d020bb 100644
--- a/database/engine/rrdengineapi.h
+++ b/database/engine/rrdengineapi.h
@@ -13,6 +13,8 @@
 #define RRDENG_FD_BUDGET_PER_INSTANCE (50)
 
 extern int db_engine_use_malloc;
+extern int default_rrdeng_page_fetch_timeout;
+extern int default_rrdeng_page_fetch_retries;
 extern int default_rrdeng_page_cache_mb;
 extern int default_rrdeng_disk_quota_mb;
 extern int default_multidb_disk_quota_mb;