thr0loc.c, srv0start.c, srv0srv.c, srv0srv.h, os0thread.h:

  Reduce InnoDB memory allocation if buffer pool < 8 MB

innobase/include/os0thread.h

@@ -15,14 +15,9 @@ Created 9/8/1995 Heikki Tuuri
 /* Maximum number of threads which can be created in the program;
 this is also the size of the wait slot array for MySQL threads which
 can wait inside InnoDB */
-#if defined(__WIN__) || defined(__NETWARE__)
-/* Create less event semaphores because Win 98/ME had difficult creating
-40000 event semaphores */
-/* TODO: these just take a lot of memory on NetWare.  should netware move up? */
-#define	OS_THREAD_MAX_N		1000
-#else
-#define	OS_THREAD_MAX_N		10000
-#endif
+
+#define	OS_THREAD_MAX_N		srv_max_n_threads
+
 
 /* Possible fixed priorities for threads */
 #define OS_THREAD_PRIORITY_NONE		100

innobase/include/srv0srv.h

@@ -87,6 +87,8 @@ extern ulint	srv_max_dirty_pages_pct;
 extern ulint	srv_force_recovery;
 extern ulint	srv_thread_concurrency;
 
+extern ulint	srv_max_n_threads;
+
 extern lint	srv_conc_n_threads;
 
 extern ibool	srv_fast_shutdown;

innobase/srv/srv0srv.c

@@ -180,6 +180,12 @@ the user from forgetting the innodb_force_recovery keyword to my.cnf */
 
 ulint	srv_force_recovery	= 0;
 /*-----------------------*/
+/* We are prepared for a situation that we have this many threads waiting for
+a semaphore inside InnoDB. innobase_start_or_create_for_mysql() sets the
+value. */
+
+ulint   srv_max_n_threads       = 0;
+
 /* The following controls how many threads we let inside InnoDB concurrently:
 threads waiting for locks are not counted into the number because otherwise
 we could get a deadlock. MySQL creates a thread for each user session, and
@@ -219,7 +225,7 @@ struct srv_conc_slot_struct{
 
 UT_LIST_BASE_NODE_T(srv_conc_slot_t)	srv_conc_queue;	/* queue of threads
 							waiting to get in */
-srv_conc_slot_t	srv_conc_slots[OS_THREAD_MAX_N];	/* array of wait
+srv_conc_slot_t* srv_conc_slots;			/* array of wait
 							slots */
 
 /* Number of times a thread is allowed to enter InnoDB within the same
@@ -1712,6 +1718,8 @@ srv_init(void)
 	
 	UT_LIST_INIT(srv_conc_queue);
 	
+	srv_conc_slots = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_conc_slot_t));
+
 	for (i = 0; i < OS_THREAD_MAX_N; i++) {
 		conc_slot = srv_conc_slots + i;
 		conc_slot->reserved = FALSE;
@@ -1758,7 +1766,7 @@ srv_conc_enter_innodb(
 			thread */
 {
 	ibool			has_slept = FALSE;
-	srv_conc_slot_t*	slot;
+	srv_conc_slot_t*	slot	  = NULL;
 	ulint			i;
 	char                    err_buf[1000];
 
@@ -1835,6 +1843,7 @@ srv_conc_enter_innodb(
 		slot = srv_conc_slots + i;
 
 		if (!slot->reserved) {
+
 			break;
 		}
 	}

innobase/srv/srv0start.c

@@ -1139,6 +1139,28 @@ innobase_start_or_create_for_mysql(void)
 	  	return(DB_ERROR);
 	}
 	
+	/* Set the maximum number of threads which can wait for a semaphore
+	inside InnoDB */
+#if defined(__WIN__) || defined(__NETWARE__)
+
+/* Create less event semaphores because Win 98/ME had difficulty creating
+40000 event semaphores.
+Comment from Novell, Inc.: also, these just take a lot of memory on
+NetWare. */
+	srv_max_n_threads = 1000;
+#else
+	if (srv_pool_size >= 8 * 1024) {
+			          /* Here we still have srv_pool_size counted
+				  in kilobytes, srv_boot converts the value to
+				  pages; if buffer pool is less than 8 MB,
+				  assume fewer threads. */
+		srv_max_n_threads = 10000;
+	} else {
+	srv_max_n_threads = 1000;	/* saves several MB of memory,
+						especially in 64-bit
+						computers */
+	}
+#endif
 	/* Note that the call srv_boot() also changes the values of
 	srv_pool_size etc. to the units used by InnoDB internally */
 

innobase/thr/thr0loc.c

@@ -14,6 +14,7 @@ Created 10/5/1995 Heikki Tuuri
 #include "sync0sync.h"
 #include "hash0hash.h"
 #include "mem0mem.h"
+#include "srv0srv.h"
 
 /*
 	IMPLEMENTATION OF THREAD LOCAL STORAGE