diff -ruN barnyard-0.2.0/src/output-plugins/op_acid_db.c barnyard-0.2.0-combined/src/output-plugins/op_acid_db.c
--- barnyard-0.2.0/src/output-plugins/op_acid_db.c	2004-04-03 13:57:32.000000000 -0600
+++ barnyard-0.2.0-combined/src/output-plugins/op_acid_db.c	2008-02-26 21:57:53.000000000 -0600
@@ -45,11 +45,20 @@
 #endif /* ENABLE_POSTGRES */
 
 /*  D A T A   S T R U C T U R E S  **************************************/
+typedef struct _DbSignature
+{
+    int gen;
+    int sid;
+    int sig_id;
+    struct DbSignature *next;
+} DbSignature;
+
 typedef struct _OpAcidDb_Data 
 {
     u_int8_t flavor;  /* what flavor of db?  MySQL, postgres, ... */
     u_int8_t detail;
     u_int16_t unused;
+    u_int32_t vseq;
     char *server;
     char *database;
     char *user;
@@ -57,6 +66,7 @@
     int sensor_id;
     u_int32_t event_id;
     int linktype;
+    DbSignature *sig_cache;
     /* db handles go here */
 #ifdef ENABLE_MYSQL
     MYSQL *mysql;
@@ -105,6 +115,11 @@
 int Insert(OpAcidDb_Data *data, char *sql, unsigned int *row_id);
 char *EscapeString(OpAcidDb_Data *data, char *string);
 
+DbSignature * AddDbSignature (DbSignature *dbsig, u_int32_t gen, u_int32_t sid, u_int32_t sig_id);
+DbSignature * RemoveDbSignature (DbSignature *dbsig);
+int FindDbSignature (DbSignature *dbsig, u_int32_t gen, u_int32_t sid, u_int32_t *sig_id);
+void ClearDbSignatures (DbSignature *dbsig);
+
 #ifdef ENABLE_MYSQL
 int MysqlConnect(OpAcidDb_Data *);
 int MysqlClose(MYSQL *mysql);
@@ -200,6 +215,8 @@
         OpAcidDb_LogConfig(outputPlugin);
     }
     
+    data->sig_cache = NULL;
+
     /* Connect to the database */
     if(DbConnect(data))
         FatalError("OpAcidDb_: Failed to connect to database: %s:%s@%s/%s\n",
@@ -254,6 +271,7 @@
     if(sid == NULL)
         sid = FakeSid(record->event.sig_generator, record->event.sig_id);
     
+    sid->rev = record->event.sig_rev;
     
     if(!(class_type = GetClassType(record->event.classification)) 
             && record->event.classification != 0)
@@ -353,6 +371,8 @@
         sid = FakeSid(record->log.event.sig_generator, record->log.event.sig_id);
     class_type = GetClassType(record->log.event.classification);
 
+    sid->rev = record->log.event.sig_rev;
+
     if((acid_sig_id = AcidDbGetSigId(op_data, sid, class_type, 
             record->log.event.priority)) == 0)
     {
@@ -721,7 +741,17 @@
 
 int AcidDbCheckSchemaVersion(OpAcidDb_Data *data)
 {
-    return 0;
+    int rval;
+
+    if(snprintf(sql_buffer, MAX_QUERY_SIZE,
+            "SELECT vseq FROM `schema` LIMIT 1") < MAX_QUERY_SIZE)
+    {
+        rval = SelectAsUInt(data, sql_buffer, &data->vseq);
+        if(data->vseq >= 106)
+            return 0;
+    }
+
+    return 1;
 }
 
 
@@ -729,7 +759,7 @@
  * Returns 1 on success
  */
 static int OpAcidDb_GetSigId(OpAcidDb_Data *op_data, char *msg, u_int32_t rev,
-        u_int32_t sid, u_int32_t *sig_id)
+        u_int32_t sid, u_int32_t gen, u_int32_t *sig_id)
 {
     int rval;
     char *e_message = NULL;
@@ -737,16 +767,43 @@
     if(!msg)
         msg = "";
 
+    if(FindDbSignature(op_data->sig_cache, gen, sid, sig_id))
+    {
+      return 1;
+    }
+
     if(!(e_message = EscapeString(op_data, msg)))
         FatalError("Failed to escape string");
 
-    if(snprintf(sql_buffer, MAX_QUERY_SIZE,
-            "SELECT sig_id FROM signature WHERE sig_name='%s' AND sig_rev=%u "
-            "AND sig_sid=%u", e_message, rev, sid) < MAX_QUERY_SIZE)
+    if(op_data->vseq >= 107)
     {
-        rval = SelectAsUInt(op_data, sql_buffer, sig_id);
-        free(e_message);
-        return rval;
+        if(snprintf(sql_buffer, MAX_QUERY_SIZE,
+                "SELECT sig_id FROM signature WHERE sig_name='%s' AND sig_rev=%u "
+                "AND sig_sid=%u AND sig_gid=%u", e_message, rev, sid, gen) < MAX_QUERY_SIZE)
+        {
+            rval = SelectAsUInt(op_data, sql_buffer, sig_id);
+            if(*sig_id != 0)
+            {
+                op_data->sig_cache = AddDbSignature(op_data->sig_cache, gen, sid, *sig_id);
+            }
+            free(e_message);
+            return rval;
+        }
+    }
+    else
+    {
+        if(snprintf(sql_buffer, MAX_QUERY_SIZE,
+                "SELECT sig_id FROM signature WHERE sig_name='%s' AND sig_rev=%u "
+                "AND sig_sid=%u", e_message, rev, sid) < MAX_QUERY_SIZE)
+        {
+            rval = SelectAsUInt(op_data, sql_buffer, sig_id);
+            if(*sig_id != 0)
+            {
+                op_data->sig_cache = AddDbSignature(op_data->sig_cache, gen, sid, *sig_id);
+            }
+            free(e_message);
+            return rval;
+        }
     }
     FatalError("SQL query too big");
     return -1;
@@ -839,7 +896,7 @@
     if(!sid)
         return 0;
     
-    if(OpAcidDb_GetSigId(op_data, sid->msg, sid->rev, sid->sid, &sig_id) == 1)
+    if(OpAcidDb_GetSigId(op_data, sid->msg, sid->rev, sid->sid, sid->gen, &sig_id) == 1)
         return sig_id;
     
     /* Create a new signature entry */
@@ -848,21 +905,51 @@
     if(!(e_message = EscapeString(op_data, sid->msg ? sid->msg : "")))
         FatalError("Failed to escape string");
     
-    if(snprintf(sql_buffer, MAX_QUERY_SIZE,
-            "INSERT INTO signature(sig_name, sig_class_id, sig_priority, "
-            "sig_rev, sig_sid) VALUES('%s', '%u', '%u', '%u', '%u')",
-            e_message, class_id, priority, sid->rev, sid->sid) < MAX_QUERY_SIZE)
-    {
-        Insert(op_data, sql_buffer, &sig_id); /* XXX: Error checking */
-        free(e_message);
-        if(sig_id == -1)
+    if (op_data->vseq >= 107)
+    {
+        if(snprintf(sql_buffer, MAX_QUERY_SIZE,
+                "INSERT INTO signature(sig_name, sig_class_id, sig_priority, "
+                "sig_rev, sig_sid, sig_gid) VALUES('%s', '%u', '%u', '%u', '%u', '%u')",
+                e_message, class_id, priority, sid->rev, sid->sid, sid->gen) < MAX_QUERY_SIZE)
+        {
+            Insert(op_data, sql_buffer, &sig_id); /* XXX: Error checking */
+            free(e_message);
+            if(sig_id == -1)
+            {
+                OpAcidDb_GetSigId(op_data, sid->msg, sid->rev, sid->sid, sid->gen, &sig_id);
+            }
+            else
+            {
+                op_data->sig_cache = AddDbSignature(op_data->sig_cache, sid->gen, sid->sid, sig_id);
+            }
+        }
+        else
         {
-            OpAcidDb_GetSigId(op_data, sid->msg, sid->rev, sid->sid, &sig_id);
+            FatalError("SQL query too big");
         }
     }
     else
     {
-        FatalError("SQL query too big");
+        if(snprintf(sql_buffer, MAX_QUERY_SIZE,
+                "INSERT INTO signature(sig_name, sig_class_id, sig_priority, "
+                "sig_rev, sig_sid) VALUES('%s', '%u', '%u', '%u', '%u')",
+                e_message, class_id, priority, sid->rev, sid->sid) < MAX_QUERY_SIZE)
+        {
+            Insert(op_data, sql_buffer, &sig_id); /* XXX: Error checking */
+            free(e_message);
+            if(sig_id == -1)
+            {
+                OpAcidDb_GetSigId(op_data, sid->msg, sid->rev, sid->sid, sid->gen, &sig_id);
+            }
+            else
+            {
+                op_data->sig_cache = AddDbSignature(op_data->sig_cache, sid->gen, sid->sid, sig_id);
+            }
+        }
+        else
+        {
+            FatalError("SQL query too big");
+        }
     }
     
     InsertSigReferences(op_data, sid->ref, sig_id);
@@ -1196,6 +1283,78 @@
     }
 }
         
+DbSignature * AddDbSignature (DbSignature *dbsig, u_int32_t gen, u_int32_t sid, u_int32_t sig_id)
+{
+
+    if(dbsig != NULL)
+    {
+        DbSignature *sig = dbsig;
+        while(dbsig->next != NULL)
+        {
+            dbsig = (DbSignature *)dbsig->next;
+        }
+        dbsig->next = (DbSignature *)SafeAlloc(sizeof(DbSignature));
+        dbsig = (DbSignature *)dbsig->next;
+        dbsig->next = NULL;
+        dbsig->gen = gen;
+        dbsig->sid = sid;
+        dbsig->sig_id = sig_id;
+        return sig;
+    }
+    else
+    {
+        dbsig = (DbSignature *)SafeAlloc(sizeof(DbSignature));
+        dbsig->next = NULL;
+        dbsig->gen = gen;
+        dbsig->sid = sid;
+        dbsig->sig_id = sig_id;
+        return dbsig;
+    }
+
+}
+
+DbSignature * RemoveDbSignature (DbSignature *dbsig)
+{
+
+    DbSignature *sig = (DbSignature *)dbsig->next;
+    free(dbsig);
+    return sig;
+
+}
+
+int FindDbSignature (DbSignature *dbsig, u_int32_t gen, u_int32_t sid, u_int32_t *sig_id)
+{
+
+    if(dbsig == NULL)
+    {
+        return 0;
+    }
+
+    while(dbsig != NULL)
+    {
+        if(dbsig->gen == gen && dbsig->sid == sid) {
+            *sig_id = dbsig->sig_id;
+            return 1;
+        }
+        dbsig = (DbSignature *)dbsig->next;
+    }
+
+    return 0;
+
+}
+
+void ClearDbSignatures (DbSignature *dbsig)
+{
+
+    if(dbsig != NULL)
+    {
+        while(dbsig != NULL)
+        {
+            dbsig = RemoveDbSignature(dbsig);
+        }
+    }
+
+}
 
 #ifdef ENABLE_MYSQL
 int MysqlConnect(OpAcidDb_Data *op_data)