ts_cache.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 643 行 · 第 1/2 页

			Datum		opt;
			bool		isnull;
			MemoryContext oldcontext;

			/*
			 * Init method runs in dictionary's private memory context, and we
			 * make sure the options are stored there too
			 */
			oldcontext = MemoryContextSwitchTo(entry->dictCtx);

			opt = SysCacheGetAttr(TSDICTOID, tpdict,
								  Anum_pg_ts_dict_dictinitoption,
								  &isnull);
			if (isnull)
				dictoptions = NIL;
			else
				dictoptions = deserialize_deflist(opt);

			entry->dictData =
				DatumGetPointer(OidFunctionCall1(template->tmplinit,
											  PointerGetDatum(dictoptions)));

			MemoryContextSwitchTo(oldcontext);
		}

		ReleaseSysCache(tptmpl);
		ReleaseSysCache(tpdict);

		fmgr_info_cxt(entry->lexizeOid, &entry->lexize, entry->dictCtx);

		entry->isvalid = true;
	}

	lastUsedDictionary = entry;

	return entry;
}

/*
 * Initialize config cache and prepare callbacks.  This is split out of
 * lookup_ts_config_cache because we need to activate the callback before
 * caching TSCurrentConfigCache, too.
 */
static void
init_ts_config_cache(void)
{
	HASHCTL		ctl;

	if (!CacheMemoryContext)
		CreateCacheMemoryContext();

	MemSet(&ctl, 0, sizeof(ctl));
	ctl.keysize = sizeof(Oid);
	ctl.entrysize = sizeof(TSConfigCacheEntry);
	ctl.hash = oid_hash;
	TSConfigCacheHash = hash_create("Tsearch configuration cache", 16,
									&ctl, HASH_ELEM | HASH_FUNCTION);
	/* Flush cache on pg_ts_config and pg_ts_config_map changes */
	CacheRegisterSyscacheCallback(TSCONFIGOID, InvalidateTSCacheCallBack,
								  PointerGetDatum(TSConfigCacheHash));
	CacheRegisterSyscacheCallback(TSCONFIGMAP, InvalidateTSCacheCallBack,
								  PointerGetDatum(TSConfigCacheHash));
}

/*
 * Fetch configuration cache entry
 */
TSConfigCacheEntry *
lookup_ts_config_cache(Oid cfgId)
{
	TSConfigCacheEntry *entry;

	if (TSConfigCacheHash == NULL)
	{
		/* First time through: initialize the hash table */
		init_ts_config_cache();
	}

	/* Check single-entry cache */
	if (lastUsedConfig && lastUsedConfig->cfgId == cfgId &&
		lastUsedConfig->isvalid)
		return lastUsedConfig;

	/* Try to look up an existing entry */
	entry = (TSConfigCacheEntry *) hash_search(TSConfigCacheHash,
											   (void *) &cfgId,
											   HASH_FIND, NULL);
	if (entry == NULL || !entry->isvalid)
	{
		/*
		 * If we didn't find one, we want to make one. But first look up the
		 * object to be sure the OID is real.
		 */
		HeapTuple	tp;
		Form_pg_ts_config cfg;
		Relation	maprel;
		Relation	mapidx;
		ScanKeyData mapskey;
		IndexScanDesc mapscan;
		HeapTuple	maptup;
		ListDictionary maplists[MAXTOKENTYPE + 1];
		Oid			mapdicts[MAXDICTSPERTT];
		int			maxtokentype;
		int			ndicts;
		int			i;

		tp = SearchSysCache(TSCONFIGOID,
							ObjectIdGetDatum(cfgId),
							0, 0, 0);
		if (!HeapTupleIsValid(tp))
			elog(ERROR, "cache lookup failed for text search configuration %u",
				 cfgId);
		cfg = (Form_pg_ts_config) GETSTRUCT(tp);

		/*
		 * Sanity checks
		 */
		if (!OidIsValid(cfg->cfgparser))
			elog(ERROR, "text search configuration %u has no parser", cfgId);

		if (entry == NULL)
		{
			bool		found;

			/* Now make the cache entry */
			entry = (TSConfigCacheEntry *)
				hash_search(TSConfigCacheHash,
							(void *) &cfgId,
							HASH_ENTER, &found);
			Assert(!found);		/* it wasn't there a moment ago */
		}
		else
		{
			/* Cleanup old contents */
			if (entry->map)
			{
				for (i = 0; i < entry->lenmap; i++)
					if (entry->map[i].dictIds)
						pfree(entry->map[i].dictIds);
				pfree(entry->map);
			}
		}

		MemSet(entry, 0, sizeof(TSConfigCacheEntry));
		entry->cfgId = cfgId;
		entry->prsId = cfg->cfgparser;

		ReleaseSysCache(tp);

		/*
		 * Scan pg_ts_config_map to gather dictionary list for each token type
		 *
		 * Because the index is on (mapcfg, maptokentype, mapseqno), we will
		 * see the entries in maptokentype order, and in mapseqno order for
		 * each token type, even though we didn't explicitly ask for that.
		 */
		MemSet(maplists, 0, sizeof(maplists));
		maxtokentype = 0;
		ndicts = 0;

		ScanKeyInit(&mapskey,
					Anum_pg_ts_config_map_mapcfg,
					BTEqualStrategyNumber, F_OIDEQ,
					ObjectIdGetDatum(cfgId));

		maprel = heap_open(TSConfigMapRelationId, AccessShareLock);
		mapidx = index_open(TSConfigMapIndexId, AccessShareLock);
		mapscan = index_beginscan(maprel, mapidx, SnapshotNow, 1, &mapskey);

		while ((maptup = index_getnext(mapscan, ForwardScanDirection)) != NULL)
		{
			Form_pg_ts_config_map cfgmap = (Form_pg_ts_config_map) GETSTRUCT(maptup);
			int			toktype = cfgmap->maptokentype;

			if (toktype <= 0 || toktype > MAXTOKENTYPE)
				elog(ERROR, "maptokentype value %d is out of range", toktype);
			if (toktype < maxtokentype)
				elog(ERROR, "maptokentype entries are out of order");
			if (toktype > maxtokentype)
			{
				/* starting a new token type, but first save the prior data */
				if (ndicts > 0)
				{
					maplists[maxtokentype].len = ndicts;
					maplists[maxtokentype].dictIds = (Oid *)
						MemoryContextAlloc(CacheMemoryContext,
										   sizeof(Oid) * ndicts);
					memcpy(maplists[maxtokentype].dictIds, mapdicts,
						   sizeof(Oid) * ndicts);
				}
				maxtokentype = toktype;
				mapdicts[0] = cfgmap->mapdict;
				ndicts = 1;
			}
			else
			{
				/* continuing data for current token type */
				if (ndicts >= MAXDICTSPERTT)
					elog(ERROR, "too many pg_ts_config_map entries for one token type");
				mapdicts[ndicts++] = cfgmap->mapdict;
			}
		}

		index_endscan(mapscan);
		index_close(mapidx, AccessShareLock);
		heap_close(maprel, AccessShareLock);

		if (ndicts > 0)
		{
			/* save the last token type's dictionaries */
			maplists[maxtokentype].len = ndicts;
			maplists[maxtokentype].dictIds = (Oid *)
				MemoryContextAlloc(CacheMemoryContext,
								   sizeof(Oid) * ndicts);
			memcpy(maplists[maxtokentype].dictIds, mapdicts,
				   sizeof(Oid) * ndicts);
			/* and save the overall map */
			entry->lenmap = maxtokentype + 1;
			entry->map = (ListDictionary *)
				MemoryContextAlloc(CacheMemoryContext,
								   sizeof(ListDictionary) * entry->lenmap);
			memcpy(entry->map, maplists,
				   sizeof(ListDictionary) * entry->lenmap);
		}

		entry->isvalid = true;
	}

	lastUsedConfig = entry;

	return entry;
}


/*---------------------------------------------------
 * GUC variable "default_text_search_config"
 *---------------------------------------------------
 */

Oid
getTSCurrentConfig(bool emitError)
{
	/* if we have a cached value, return it */
	if (OidIsValid(TSCurrentConfigCache))
		return TSCurrentConfigCache;

	/* fail if GUC hasn't been set up yet */
	if (TSCurrentConfig == NULL || *TSCurrentConfig == '\0')
	{
		if (emitError)
			elog(ERROR, "text search configuration isn't set");
		else
			return InvalidOid;
	}

	if (TSConfigCacheHash == NULL)
	{
		/* First time through: initialize the tsconfig inval callback */
		init_ts_config_cache();
	}

	/* Look up the config */
	TSCurrentConfigCache =
		TSConfigGetCfgid(stringToQualifiedNameList(TSCurrentConfig),
						 !emitError);

	return TSCurrentConfigCache;
}

const char *
assignTSCurrentConfig(const char *newval, bool doit, GucSource source)
{
	/*
	 * If we aren't inside a transaction, we cannot do database access so
	 * cannot verify the config name.  Must accept it on faith.
	 */
	if (IsTransactionState())
	{
		Oid			cfgId;
		HeapTuple	tuple;
		Form_pg_ts_config cfg;
		char	   *buf;

		cfgId = TSConfigGetCfgid(stringToQualifiedNameList(newval), true);

		if (!OidIsValid(cfgId))
			return NULL;

		/*
		 * Modify the actually stored value to be fully qualified, to ensure
		 * later changes of search_path don't affect it.
		 */
		tuple = SearchSysCache(TSCONFIGOID,
							   ObjectIdGetDatum(cfgId),
							   0, 0, 0);
		if (!HeapTupleIsValid(tuple))
			elog(ERROR, "cache lookup failed for text search configuration %u",
				 cfgId);
		cfg = (Form_pg_ts_config) GETSTRUCT(tuple);

		buf = quote_qualified_identifier(get_namespace_name(cfg->cfgnamespace),
										 NameStr(cfg->cfgname));

		ReleaseSysCache(tuple);

		/* GUC wants it malloc'd not palloc'd */
		newval = strdup(buf);
		pfree(buf);

		if (doit && newval)
			TSCurrentConfigCache = cfgId;
	}
	else
	{
		if (doit)
			TSCurrentConfigCache = InvalidOid;
	}

	return newval;
}