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-rw-r--r-- | sql/sp_cache.cc | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/sql/sp_cache.cc b/sql/sp_cache.cc new file mode 100644 index 00000000..b3949a94 --- /dev/null +++ b/sql/sp_cache.cc @@ -0,0 +1,314 @@ +/* Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ + +#include "mariadb.h" +#include "sql_priv.h" +#include "unireg.h" +#ifdef USE_PRAGMA_IMPLEMENTATION +#pragma implementation +#endif +#include "sp_cache.h" +#include "sp_head.h" + +static mysql_mutex_t Cversion_lock; +static ulong volatile Cversion= 1; + + +/* + Cache of stored routines. +*/ + +class sp_cache +{ +public: + sp_cache(); + ~sp_cache(); + + /** + Inserts a sp_head object into a hash table. + + @returns Success status + @return TRUE Failure + @return FALSE Success + */ + inline bool insert(sp_head *sp) + { + return my_hash_insert(&m_hashtable, (const uchar *)sp); + } + + inline sp_head *lookup(char *name, size_t namelen) + { + return (sp_head *) my_hash_search(&m_hashtable, (const uchar *)name, + namelen); + } + + inline void remove(sp_head *sp) + { + my_hash_delete(&m_hashtable, (uchar *)sp); + } + + /** + Remove all elements from a stored routine cache if the current + number of elements exceeds the argument value. + + @param[in] upper_limit_for_elements Soft upper limit of elements that + can be stored in the cache. + */ + void enforce_limit(ulong upper_limit_for_elements) + { + if (m_hashtable.records > upper_limit_for_elements) + my_hash_reset(&m_hashtable); + } + +private: + void init(); + void cleanup(); + + /* All routines in this cache */ + HASH m_hashtable; +}; // class sp_cache + +#ifdef HAVE_PSI_INTERFACE +static PSI_mutex_key key_Cversion_lock; + +static PSI_mutex_info all_sp_cache_mutexes[]= +{ + { &key_Cversion_lock, "Cversion_lock", PSI_FLAG_GLOBAL} +}; + +static void init_sp_cache_psi_keys(void) +{ + const char* category= "sql"; + int count; + + if (PSI_server == NULL) + return; + + count= array_elements(all_sp_cache_mutexes); + PSI_server->register_mutex(category, all_sp_cache_mutexes, count); +} +#endif + +/* Initialize the SP caching once at startup */ + +void sp_cache_init() +{ +#ifdef HAVE_PSI_INTERFACE + init_sp_cache_psi_keys(); +#endif + + mysql_mutex_init(key_Cversion_lock, &Cversion_lock, MY_MUTEX_INIT_FAST); +} + + +/* + Clear the cache *cp and set *cp to NULL. + + SYNOPSIS + sp_cache_clear() + cp Pointer to cache to clear + + NOTE + This function doesn't invalidate other caches. +*/ + +void sp_cache_clear(sp_cache **cp) +{ + sp_cache *c= *cp; + + if (c) + { + delete c; + *cp= NULL; + } +} + + +void sp_cache_end() +{ + mysql_mutex_destroy(&Cversion_lock); +} + + +/* + Insert a routine into the cache. + + SYNOPSIS + sp_cache_insert() + cp The cache to put routine into + sp Routine to insert. + + TODO: Perhaps it will be more straightforward if in case we returned an + error from this function when we couldn't allocate sp_cache. (right + now failure to put routine into cache will cause a 'SP not found' + error to be reported at some later time) +*/ + +void sp_cache_insert(sp_cache **cp, sp_head *sp) +{ + sp_cache *c; + + if (!(c= *cp)) + { + if (!(c= new sp_cache())) + return; // End of memory error + } + /* Reading a ulong variable with no lock. */ + sp->set_sp_cache_version(Cversion); + DBUG_PRINT("info",("sp_cache: inserting: %s", ErrConvDQName(sp).ptr())); + c->insert(sp); + *cp= c; // Update *cp if it was NULL +} + + +/* + Look up a routine in the cache. + SYNOPSIS + sp_cache_lookup() + cp Cache to look into + name Name of rutine to find + + NOTE + An obsolete (but not more obsolete then since last + sp_cache_flush_obsolete call) routine may be returned. + + RETURN + The routine or + NULL if the routine not found. +*/ + +sp_head *sp_cache_lookup(sp_cache **cp, const Database_qualified_name *name) +{ + char buf[NAME_LEN * 2 + 2]; + sp_cache *c= *cp; + if (! c) + return NULL; + return c->lookup(buf, name->make_qname(buf, sizeof(buf))); +} + + +/* + Invalidate all routines in all caches. + + SYNOPSIS + sp_cache_invalidate() + + NOTE + This is called when a VIEW definition is created or modified (and in some + other contexts). We can't destroy sp_head objects here as one may modify + VIEW definitions from prelocking-free SPs. +*/ + +void sp_cache_invalidate() +{ + DBUG_PRINT("info",("sp_cache: invalidating")); + thread_safe_increment(Cversion, &Cversion_lock); +} + + +/** + Remove an out-of-date SP from the cache. + + @param[in] cp Cache to flush + @param[in] sp SP to remove. + + @note This invalidates pointers to sp_head objects this thread + uses. In practice that means don't call this function when + inside SP'. +*/ + +void sp_cache_flush_obsolete(sp_cache **cp, sp_head **sp) +{ + if ((*sp)->sp_cache_version() < Cversion && !(*sp)->is_invoked()) + { + (*cp)->remove(*sp); + *sp= NULL; + } +} + +/** + Return the current global version of the cache. +*/ + +ulong sp_cache_version() +{ + return Cversion; +} + + +/** + Enforce that the current number of elements in the cache don't exceed + the argument value by flushing the cache if necessary. + + @param[in] c Cache to check + @param[in] upper_limit_for_elements Soft upper limit for number of sp_head + objects that can be stored in the cache. +*/ +void +sp_cache_enforce_limit(sp_cache *c, ulong upper_limit_for_elements) +{ + if (c) + c->enforce_limit(upper_limit_for_elements); +} + +/************************************************************************* + Internal functions + *************************************************************************/ + +extern "C" uchar *hash_get_key_for_sp_head(const uchar *ptr, size_t *plen, + my_bool first); +extern "C" void hash_free_sp_head(void *p); + +uchar *hash_get_key_for_sp_head(const uchar *ptr, size_t *plen, + my_bool first) +{ + sp_head *sp= (sp_head *)ptr; + *plen= sp->m_qname.length; + return (uchar*) sp->m_qname.str; +} + + +void hash_free_sp_head(void *p) +{ + sp_head *sp= (sp_head *)p; + sp_head::destroy(sp); +} + + +sp_cache::sp_cache() +{ + init(); +} + + +sp_cache::~sp_cache() +{ + my_hash_free(&m_hashtable); +} + + +void +sp_cache::init() +{ + my_hash_init(key_memory_sp_cache, &m_hashtable, system_charset_info, 0, 0, 0, + hash_get_key_for_sp_head, hash_free_sp_head, 0); +} + + +void +sp_cache::cleanup() +{ + my_hash_free(&m_hashtable); +} |