Revert "LACOUNT: Add back lacount mechanism to defer migrating a fetched/read copy until after default of 20 consecutive requests from the same node"

This reverts commit 035c0d981bde8c0eee8b3f24ba8e2dc817e5b504.

This is a premature optimization.  Record can bounce between nodes
very quickly if it is a contended record.  There is no need to hold a
record on a node unnecessarily.  In case record contention becomes bad,
enabling sticky records on a database is a better idea.

Conflicts:
	include/ctdb_private.h
	server/ctdb_tunables.c

Signed-off-by: Amitay Isaacs <amitay@gmail.com>

(This used to be ctdb commit ac417b0003f0116f116834ad2ac51482d25cfa0d)

1 files changed, 8 insertions, 12 deletions

diff --git a/ctdb/server/ctdb_call.c b/ctdb/server/ctdb_call.c
index bda599acc84..017e4f575ce 100644
--- a/ctdb/server/ctdb_call.c
+++ b/ctdb/server/ctdb_call.c
@@ -399,7 +399,7 @@ static void ctdb_become_dmaster(struct ctdb_db_context *ctdb_db,
 		return;
 	}
 
-	ctdb_call_local(ctdb_db, state->call, &header, state, &data, true, ctdb->pnn);
+	ctdb_call_local(ctdb_db, state->call, &header, state, &data, true);
 
 	ret = ctdb_ltdb_unlock(ctdb_db, state->call->key);
 	if (ret != 0) {
@@ -930,15 +930,11 @@ void ctdb_request_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
 	}
 
 
-	/* if this nodes has done enough consecutive calls on the same record
-	   then give them the record
-	   or if the node requested an immediate migration
-	*/
-	if ( c->hdr.srcnode != ctdb->pnn &&
-	     ((header.laccessor == c->hdr.srcnode
-	       && header.lacount >= ctdb->tunable.max_lacount
-	       && ctdb->tunable.max_lacount != 0)
-	      || (c->flags & CTDB_IMMEDIATE_MIGRATION)) ) {
+	/* Try if possible to migrate the record off to the caller node.
+	 * From the clients perspective a fetch of the data is just as 
+	 * expensive as a migration.
+	 */
+	if (c->hdr.srcnode != ctdb->pnn) {
 		if (ctdb_db->transaction_active) {
 			DEBUG(DEBUG_INFO, (__location__ " refusing migration"
 			      " of key %s while transaction is active\n",
@@ -957,7 +953,7 @@ void ctdb_request_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
 		}
 	}
 
-	ret = ctdb_call_local(ctdb_db, call, &header, hdr, &data, true, c->hdr.srcnode);
+	ret = ctdb_call_local(ctdb_db, call, &header, hdr, &data, true);
 	if (ret != 0) {
 		DEBUG(DEBUG_ERR,(__location__ " ctdb_call_local failed\n"));
 		call->status = -1;
@@ -1244,7 +1240,7 @@ struct ctdb_call_state *ctdb_call_local_send(struct ctdb_db_context *ctdb_db,
 	*(state->call) = *call;
 	state->ctdb_db = ctdb_db;
 
-	ret = ctdb_call_local(ctdb_db, state->call, header, state, data, true, ctdb->pnn);
+	ret = ctdb_call_local(ctdb_db, state->call, header, state, data, true);
 	if (ret != 0) {
 		DEBUG(DEBUG_DEBUG,("ctdb_call_local() failed, ignoring return code %d\n", ret));
 	}