Default schema change saving to 7.0 format to allow schema changes to…

… race with server upgrade.

To run the testcase you need to setup a mixed cluster by hand and run the script like
./runit dbname oneofthenodes

Signed-off-by: Dorin Hogea <dhogea@bloomberg.net>

bdb/llmeta.c

@@ -11061,53 +11061,3 @@ int bdb_del_view(tran_type *t, const char *view_name)
     }
     return rc;
 }
-
-#include "schemachange.h"
-
-/*
-  DRQS-170879936:
-
-  In version R8, some backwards incompatible changes got introduced into
-  the schema change object that broke the object's original deserializer
-  function (buf_get_schemachange()). As a result, reading an sc status object
-  created by R7 would fail if read by R8 (via comdb2_sc_status).
-
-  The fix was to keep the both the versions of the deserializer functions and
-  invoke them appropriately.
-
-  The current (potential hackish) method to pick the right version on the
-  deserializer function is based on the content of the first 4 bytes of the
-  LLMETA_SCHEMACHANGE_STATUS payload, where it is assumed that the valid
-  values of s->kind (between SC_INVALID and SC_LAST, exclusive) will not
-  coincide with the first 4 bytes of the rqid (fastseed) stored as the first
-  member in old (7.0's) LLMETA_SCHEMACHANGE_STATUS payload.
-*/
-static int buf_get_schemachange_key_type(void *p_buf, void *p_buf_end)
-{
-    int first = 0;
-
-    if (p_buf >= p_buf_end) return -1;
-
-    buf_get(&first, sizeof(first), p_buf, p_buf_end);
-
-    if (first > SC_INVALID && first < SC_LAST) {
-        return LLMETA_SCHEMACHANGE_STATUS_V2;
-    }
-    return LLMETA_SCHEMACHANGE_STATUS;
-}
-
-void *buf_get_schemachange(struct schema_change_type *s, void *p_buf,
-                           void *p_buf_end)
-{
-    int sc_key_type = buf_get_schemachange_key_type(p_buf, p_buf_end);
-
-    switch (sc_key_type) {
-    case LLMETA_SCHEMACHANGE_STATUS:
-        return buf_get_schemachange_v1(s, (void *)p_buf, (void *)p_buf_end);
-    case LLMETA_SCHEMACHANGE_STATUS_V2:
-        return buf_get_schemachange_v2(s, (void *)p_buf, (void *)p_buf_end);
-    default:
-        break;
-    }
-    return NULL;
-}

db/db_tunables.c

@@ -483,6 +483,7 @@ extern int gbl_timer_warn_interval;
 int gbl_incoherent_clnt_wait = 0;
 int gbl_new_leader_duration = 3;
 extern int gbl_transaction_grace_period;
+extern int gbl_sc_7format;
 extern int gbl_dohsql_joins;
 extern int gbl_sc_history_max_rows;
 extern int gbl_sc_status_max_rows;

db/db_tunables.h

@@ -2504,6 +2504,10 @@ REGISTER_TUNABLE("transaction_grace_period",
                  "Time to wait for connections with pending transactions to go away on exit. (Default: 60)",
                  TUNABLE_INTEGER, &gbl_transaction_grace_period, 0, NULL, NULL, NULL, NULL);
 
+REGISTER_TUNABLE("sc_7format",
+                 "Save schema change object in 7.0 format. (Default: off)",
+                 TUNABLE_BOOLEAN, &gbl_sc_7format, INTERNAL, NULL, NULL, NULL, NULL);
+
 REGISTER_TUNABLE("dohsql_joins",
                  "Enable to support joins in parallel sql execution (default: on)",
                  TUNABLE_BOOLEAN, &gbl_dohsql_joins, 0, NULL, NULL, NULL, NULL);

db/osqlcomm.c

@@ -7759,10 +7759,7 @@ int osql_send_schemachange(osql_target_t *target, unsigned long long rqid,
 {
 
     schemachange_packed_size(sc);
-    size_t osql_rpl_size =
-        ((rqid == OSQL_RQID_USE_UUID) ? OSQLCOMM_UUID_RPL_TYPE_LEN
-                                      : OSQLCOMM_RPL_TYPE_LEN) +
-        sc->packed_len;
+    size_t osql_rpl_size = OSQLCOMM_UUID_RPL_TYPE_LEN + sc->packed_len;
     uint8_t *buf = alloca(osql_rpl_size);
     uint8_t *p_buf = buf;
     uint8_t *p_buf_end = p_buf + osql_rpl_size;
@@ -7773,32 +7770,17 @@ int osql_send_schemachange(osql_target_t *target, unsigned long long rqid,
 
     strcpy(sc->original_master_node, target->host);
 
-    if (rqid == OSQL_RQID_USE_UUID) {
-        osql_uuid_rpl_t hd_uuid = {0};
+    osql_uuid_rpl_t hd_uuid = {0};
 
-        hd_uuid.type = OSQL_SCHEMACHANGE;
-        comdb2uuidcpy(hd_uuid.uuid, uuid);
-        if (!(p_buf = osqlcomm_schemachange_uuid_rpl_type_put(
-                  &hd_uuid, sc, p_buf, p_buf_end))) {
-            logmsg(LOGMSG_ERROR, "%s:%s returns NULL\n", __func__,
-                   "osqlcomm_schemachange_uuid_rpl_type_put");
-            return -1;
-        }
-
-        type = osql_net_type_to_net_uuid_type(NET_OSQL_SOCK_RPL);
-    } else {
-        osql_rpl_t hd = {0};
-
-        hd.type = OSQL_SCHEMACHANGE;
-        hd.sid = rqid;
-
-        if (!(p_buf = osqlcomm_schemachange_rpl_type_put(&hd, sc, p_buf,
-                                                         p_buf_end))) {
-            logmsg(LOGMSG_ERROR, "%s:%s returns NULL\n", __func__,
-                   "osqlcomm_schemachange_rpl_type_put");
-            return -1;
-        }
+    hd_uuid.type = OSQL_SCHEMACHANGE;
+    comdb2uuidcpy(hd_uuid.uuid, uuid);
+    if (!(p_buf = osqlcomm_schemachange_uuid_rpl_type_put(
+                    &hd_uuid, sc, p_buf, p_buf_end))) {
+        logmsg(LOGMSG_ERROR, "%s:%s returns NULL\n", __func__,
+                "osqlcomm_schemachange_uuid_rpl_type_put");
+        return -1;
     }
+    type = osql_net_type_to_net_uuid_type(NET_OSQL_SOCK_RPL);
 
     if (gbl_enable_osql_logging) {
         logmsg(LOGMSG_DEBUG, "[%llu %s] send OSQL_SCHEMACHANGE %s\n", rqid,