Some small fixes to the query cache.

4 files changed, 66 insertions, 51 deletions

diff --git a/Docs/manual.texi b/Docs/manual.texi
index 4dc3b089d3a..5715f788845 100644
--- a/Docs/manual.texi
+++ b/Docs/manual.texi
@@ -4744,22 +4744,23 @@ MySQL Server offers the following advantages over PostgreSQL:
 
 @itemize @bullet
 @item
-@code{MySQL} Server is generally much faster than PostgreSQL.
+@code{MySQL} Server is generally much faster than PostgreSQL.  MySQL
+4.0.1 has also a query cache that can boost up the query speed for
+mostly-read-only sites many times.
 
 @item
-MySQL has a much larger user base than PostgreSQL, therefore the
-code is more tested and has historically proven more stable than
-PostgreSQL.  MySQL Server is the much more used in production
-environments than PostgreSQL, mostly thanks to that MySQL AB,
-formerly TCX DataKonsult AB, has provided top quality commercial support
-for MySQL Server from the day it was released, whereas until recently
-PostgreSQL was unsupported.
+MySQL has a much larger user base than PostgreSQL, therefore the code is
+more tested and has historically proven more stable than PostgreSQL.
+MySQL Server is more used in production environments than PostgreSQL,
+mostly thanks to that MySQL AB, formerly TCX DataKonsult AB, has
+provided top quality commercial support for MySQL Server from the day it
+was released, whereas until recently PostgreSQL was unsupported.
 
 @item
-MySQL Server works better on Windows than PostgreSQL does.  MySQL Server runs as a
-native Windows application (a service on NT/Win2000/WinXP), while
-PostgreSQL is run under the @code{Cygwin} emulation.  We have heard
-that PostgreSQL is not yet that stable on Windows but we haven't
+MySQL Server works better on Windows than PostgreSQL does.  MySQL Server
+runs as a native Windows application (a service on NT/Win2000/WinXP),
+while PostgreSQL is run under the @code{Cygwin} emulation.  We have
+heard that PostgreSQL is not yet that stable on Windows but we haven't
 been able to verify this ourselves.
 
 @item
@@ -4844,19 +4845,21 @@ You can access many databases from the same connection (depending of course
 on your privileges).
 
 @item
-MySQL Server is coded from the start to be multi-threaded while PostgreSQL uses
-processes.  Context switching and access to common storage areas is much 
-faster between threads than between separate processes, this gives MySQL Server
-a big speed advantage in multi-user applications and also makes it easier
-for MySQL Server to take full advantage of symmetric multiprocessor (SMP) systems.
+MySQL Server is coded from the start to be multi-threaded while
+PostgreSQL uses processes.  Context switching and access to common
+storage areas is much faster between threads than between separate
+processes, this gives MySQL Server a big speed advantage in multi-user
+applications and also makes it easier for MySQL Server to take full
+advantage of symmetric multiprocessor (SMP) systems.
 
 @item
-MySQL Server has a much more sophisticated privilege system than PostgreSQL.  
-While PostgreSQL only supports @code{INSERT}, @code{SELECT}, and
-@code{UPDATE/DELETE} grants per user on a database or a table, MySQL Server allows
-you to define a full set of different privileges on database, table and 
-column level.  MySQL Server also allows you to specify the privilege on host and 
-user combinations.  @xref{GRANT}.
+MySQL Server has a much more sophisticated privilege system than
+PostgreSQL.  While PostgreSQL only supports @code{INSERT},
+@code{SELECT}, and @code{UPDATE/DELETE} grants per user on a database or
+a table, MySQL Server allows you to define a full set of different
+privileges on database, table and column level.  MySQL Server also
+allows you to specify the privilege on host and user combinations.
+@xref{GRANT}.
 
 @item
 MySQL Server supports a compressed client/server protocol which improves 
@@ -4880,16 +4883,17 @@ of a data file happens, usually from a hardware failure.  It allows a
 majority of the data to be recovered.
 
 @item
-Upgrading MySQL Server is painless.  When you are upgrading MySQL Server, you don't need
-to dump/restore your data, as you have to do with most PostgreSQL upgrades.
+Upgrading MySQL Server is painless.  When you are upgrading MySQL
+Server, you don't need to dump/restore your data, as you have to do with
+most PostgreSQL upgrades.
 @end itemize
 
 Drawbacks with MySQL Server compared to PostgreSQL:
 
 @itemize @bullet
 @item
-The transaction support in MySQL Server is not yet as well tested as PostgreSQL's
-system.
+The transaction support in MySQL Server is not yet as well tested as
+PostgreSQL's system.
 
 @item
 Because MySQL Server uses threads, which are not yet flawless on many OSes, one
@@ -4914,10 +4918,10 @@ as in PostgreSQL.  @xref{Adding functions}.
 
 @item
 Updates that run over multiple tables is harder to do in MySQL Server.
-This will, however, be fixed in MySQL Server 4.0 with multi-table @code{UPDATE}
-and in MySQL Server 4.1 with subselects.
-In MySQL Server 4.0 one can use multi-table deletes to delete from many tables
-at the same time. @xref{DELETE}.
+This will, however, be fixed in MySQL Server 4.0.2 with multi-table
+@code{UPDATE} and in MySQL Server 4.1 with subselects.  In MySQL Server
+4.0 one can use multi-table deletes to delete from many tables at the
+same time. @xref{DELETE}.
 @end itemize
 
 PostgreSQL currently offers the following advantages over MySQL Server:
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index 9c29b594621..8f55a02b020 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -1127,7 +1127,7 @@ longlong Item_extract::val_int()
 
 void Item_typecast::print(String *str)
 {
-  str->append("CASE(");
+  str->append("CAST(");
   args[0]->print(str);
   str->append(" AS ");
   str->append(func_name());
diff --git a/sql/sql_cache.cc b/sql/sql_cache.cc
index e21a674eb07..142170d022c 100644
--- a/sql/sql_cache.cc
+++ b/sql/sql_cache.cc
@@ -344,7 +344,8 @@ inline Query_cache_block * Query_cache_block_table::block()
 void Query_cache_block::init(ulong block_length)
 {
   DBUG_ENTER("Query_cache_block::init");
-  DBUG_PRINT("qcache", ("init block 0x%lx", (ulong) this));
+  DBUG_PRINT("qcache", ("init block 0x%lx  length: %lu", (ulong) this,
+			block_length));
   length = block_length;
   used = 0;
   type = Query_cache_block::FREE;
@@ -587,7 +588,7 @@ void query_cache_insert(NET *net, const char *packet, ulong length)
   }
   else
     STRUCT_UNLOCK(&query_cache.structure_guard_mutex);
-  DBUG_EXECUTE("check_querycache",query_cache.check_integrity(););
+  DBUG_EXECUTE("check_querycache",query_cache.check_integrity(0););
   DBUG_VOID_RETURN;
 }
 
@@ -615,7 +616,7 @@ void query_cache_abort(NET *net)
     }
     net->query_cache_query=0;
     STRUCT_UNLOCK(&query_cache.structure_guard_mutex);
-    DBUG_EXECUTE("check_querycache",query_cache.check_integrity(););
+    DBUG_EXECUTE("check_querycache",query_cache.check_integrity(0););
   }
   DBUG_VOID_RETURN;
 }
@@ -662,7 +663,7 @@ void query_cache_end_of_result(NET *net)
       STRUCT_UNLOCK(&query_cache.structure_guard_mutex);
     }
     net->query_cache_query=0;
-    DBUG_EXECUTE("check_querycache",query_cache.check_integrity(););
+    DBUG_EXECUTE("check_querycache",query_cache.check_integrity(0););
   }
   DBUG_VOID_RETURN;
 }
@@ -670,7 +671,7 @@ void query_cache_end_of_result(NET *net)
 void query_cache_invalidate_by_MyISAM_filename(const char *filename)
 {
   query_cache.invalidate_by_MyISAM_filename(filename);
-  DBUG_EXECUTE("check_querycache",query_cache.check_integrity(););
+  DBUG_EXECUTE("check_querycache",query_cache.check_integrity(0););
 }
 
 
@@ -2482,6 +2483,7 @@ my_bool Query_cache::move_by_type(byte **border,
 		      *pprev = block->pprev,
 		      *pnext = block->pnext,
 		      *new_block =(Query_cache_block *) *border;
+    uint tablename_offset = block->table()->table() - block->table()->db();
     char *data = (char*) block->data();
     byte *key;
     uint key_length;
@@ -2493,7 +2495,7 @@ my_bool Query_cache::move_by_type(byte **border,
     new_block->type=Query_cache_block::TABLE;
     new_block->used=used;
     new_block->n_tables=1;
-    memcpy((char*) new_block->data(), data, len-new_block->headers_len());
+    memmove((char*) new_block->data(), data, len-new_block->headers_len());
     relink(block, new_block, next, prev, pnext, pprev);
     if (tables_blocks[new_block->table()->type()] == block)
       tables_blocks[new_block->table()->type()] = new_block;
@@ -2515,10 +2517,18 @@ my_bool Query_cache::move_by_type(byte **border,
       nlist_root->prev = tnext;
       tprev->next = nlist_root;
     }
+
+    /*
+      Go through all queries that uses this table and change them to
+      point to the new table object
+    */
+    Query_cache_table *new_block_table=new_block->table();
     for (;tnext != nlist_root; tnext=tnext->next)
-      tnext->parent = new_block->table();
+      tnext->parent= new_block_table;
     *border += len;
     *before = new_block;
+    /* Fix pointer to table name */
+    new_block->table()->table(new_block->table()->db() + tablename_offset);
     /* Fix hash to point at moved block */
     hash_replace(&tables, tables.current_record, (byte*) new_block);
 
@@ -2546,8 +2556,8 @@ my_bool Query_cache::move_by_type(byte **border,
     uint key_length;
     key=query_cache_query_get_key((byte*) block, &key_length, 0);
     hash_search(&queries, (byte*) key, key_length);
-
-    memcpy((char*) new_block->table(0), (char*) block->table(0),
+    // Move table of used tables 
+    memmove((char*) new_block->table(0), (char*) block->table(0),
 	   ALIGN_SIZE(n_tables*sizeof(Query_cache_block_table)));
     block->query()->unlock_n_destroy();
     block->destroy();
@@ -2555,7 +2565,7 @@ my_bool Query_cache::move_by_type(byte **border,
     new_block->type=Query_cache_block::QUERY;
     new_block->used=used;
     new_block->n_tables=n_tables;
-    memcpy((char*) new_block->data(), data, len - new_block->headers_len());
+    memmove((char*) new_block->data(), data, len - new_block->headers_len());
     relink(block, new_block, next, prev, pnext, pprev);
     if (queries_blocks == block)
       queries_blocks = new_block;
@@ -2620,7 +2630,7 @@ my_bool Query_cache::move_by_type(byte **border,
     new_block->init(len);
     new_block->type=type;
     new_block->used=used;
-    memcpy((char*) new_block->data(), data, len - new_block->headers_len());
+    memmove((char*) new_block->data(), data, len - new_block->headers_len());
     relink(block, new_block, next, prev, pnext, pprev);
     new_block->result()->parent(query_block);
     Query_cache_query *query = query_block->query();
@@ -2786,7 +2796,7 @@ void bins_dump() {}
 void cache_dump() {}
 void queries_dump() {}
 void tables_dump() {}
-my_bool check_integrity() { return 0; }
+my_bool check_integrity(bool not_locked) { return 0; }
 my_bool in_list(Query_cache_block * root, Query_cache_block * point,
 		const char *name) { return 0;}
 my_bool in_blocks(Query_cache_block * point) { return 0; }
@@ -2806,7 +2816,7 @@ void Query_cache::wreck(uint line, const char *message)
   if (thd)
     thd->killed = 1;
   cache_dump();
-  /* check_integrity(); */ /* Can't call it here because of locks */
+  /* check_integrity(0); */ /* Can't call it here because of locks */
   bins_dump();
   DBUG_VOID_RETURN;
 }
@@ -2977,19 +2987,19 @@ void Query_cache::tables_dump()
 }
 
 
-my_bool Query_cache::check_integrity()
+my_bool Query_cache::check_integrity(bool not_locked)
 {
   my_bool result = 0;
   uint i;
-  STRUCT_LOCK(&structure_guard_mutex);
   DBUG_ENTER("check_integrity");
 
-  if ( !initialized )
+  if (!initialized )
   {
-    STRUCT_UNLOCK(&structure_guard_mutex);
     DBUG_PRINT("qcache", ("Query Cache not initialized"));
     DBUG_RETURN(0);
   }
+  if (!not_locked)
+    STRUCT_LOCK(&structure_guard_mutex);
 
   if (hash_check(&queries))
   {
@@ -3213,7 +3223,8 @@ my_bool Query_cache::check_integrity()
     }
   }
   DBUG_ASSERT(result == 0);
-  STRUCT_UNLOCK(&structure_guard_mutex);
+  if (!not_locked)
+    STRUCT_UNLOCK(&structure_guard_mutex);
   DBUG_RETURN(result);
 }
 
diff --git a/sql/sql_cache.h b/sql/sql_cache.h
index bde11d2dbb6..4c1a5950546 100644
--- a/sql/sql_cache.h
+++ b/sql/sql_cache.h
@@ -391,7 +391,7 @@ protected:
   void cache_dump();
   void queries_dump();
   void tables_dump();
-  my_bool check_integrity();
+  my_bool check_integrity(bool not_locked);
   my_bool in_list(Query_cache_block * root, Query_cache_block * point,
 		  const char *name);
   my_bool in_blocks(Query_cache_block * point);