fixes #152 Add accounting for long input buffer wait stalls in the

logger

ft/log-internal.h

@@ -177,6 +177,7 @@ struct tokulogger {
     uint64_t num_writes_to_disk;         // how many times did we write to disk?
     uint64_t bytes_written_to_disk;        // how many bytes have been written to disk?
     tokutime_t time_spent_writing_to_disk; // how much tokutime did we spend writing to disk?
+    uint64_t num_wait_buf_long;            // how many times we waited >= 100ms for the in buf
 
     void (*remove_finalize_callback) (DICTIONARY_ID, void*);  // ydb-level callback to be called when a transaction that ...
     void * remove_finalize_callback_extra;                    // ... deletes a file is committed or when one that creates a file is aborted.

ft/logger.cc

@@ -422,9 +422,13 @@ wait_till_output_available (TOKULOGGER logger)
 // Exit: Holds the output_condition_lock and logger->output_is_available
 // 
 {
+    tokutime_t t0 = toku_time_now();
     while (!logger->output_is_available) {
         toku_cond_wait(&logger->output_condition, &logger->output_condition_lock);
     }
+    if (tokutime_to_seconds(toku_time_now() - t0) >= 0.100) {
+        logger->num_wait_buf_long++;
+    }
 }
 
 static void
@@ -1397,6 +1401,7 @@ status_init(void) {
     STATUS_INIT(LOGGER_BYTES_WRITTEN,               LOGGER_WRITES_BYTES, UINT64,  "writes (bytes)", TOKU_ENGINE_STATUS|TOKU_GLOBAL_STATUS);
     STATUS_INIT(LOGGER_UNCOMPRESSED_BYTES_WRITTEN,  LOGGER_WRITES_UNCOMPRESSED_BYTES, UINT64,  "writes (uncompressed bytes)", TOKU_ENGINE_STATUS|TOKU_GLOBAL_STATUS);
     STATUS_INIT(LOGGER_TOKUTIME_WRITES,             LOGGER_WRITES_SECONDS, TOKUTIME,  "writes (seconds)", TOKU_ENGINE_STATUS|TOKU_GLOBAL_STATUS);
+    STATUS_INIT(LOGGER_WAIT_BUF_LONG,               LOGGER_WAIT_LONG, UINT64,  "count", TOKU_ENGINE_STATUS|TOKU_GLOBAL_STATUS);
     logger_status.initialized = true;
 }
 #undef STATUS_INIT
@@ -1414,6 +1419,7 @@ toku_logger_get_status(TOKULOGGER logger, LOGGER_STATUS statp) {
         // No compression on logfiles so the uncompressed size is just number of bytes written
         STATUS_VALUE(LOGGER_UNCOMPRESSED_BYTES_WRITTEN)  = logger->bytes_written_to_disk;
         STATUS_VALUE(LOGGER_TOKUTIME_WRITES) = logger->time_spent_writing_to_disk;
+        STATUS_VALUE(LOGGER_WAIT_BUF_LONG) = logger->num_wait_buf_long;
     }
     *statp = logger_status;
 }

ft/logger.h

@@ -244,6 +244,7 @@ typedef enum {
     LOGGER_BYTES_WRITTEN,
     LOGGER_UNCOMPRESSED_BYTES_WRITTEN,
     LOGGER_TOKUTIME_WRITES,
+    LOGGER_WAIT_BUF_LONG,
     LOGGER_STATUS_NUM_ROWS
 } logger_status_entry;