Use saved long-lived memory context for constructing dictionary after dict's reset

Author: feodor

contrib/shared_ispell/expected/shared_ispell.out

@@ -211,3 +211,9 @@ SELECT ts_lexize('shared_hunspell', 'skies');
  {sky}
 (1 row)
 
+SELECT ts_lexize('shared_hunspell', 'skies');
+ ts_lexize 
+-----------
+ {sky}
+(1 row)
+

contrib/shared_ispell/sql/shared_ispell.sql

@@ -53,4 +53,5 @@ SELECT stop_name, words FROM shared_ispell_stoplists();
 SELECT shared_ispell_reset();
 
 SELECT ts_lexize('shared_ispell', 'skies');
-SELECT ts_lexize('shared_hunspell', 'skies');
+SELECT ts_lexize('shared_hunspell', 'skies');
+SELECT ts_lexize('shared_hunspell', 'skies');

contrib/shared_ispell/src/shared_ispell.c

@@ -294,13 +294,9 @@ static void
 init_shared_dict(DictInfo *info, char *dictFile, char *affFile, char *stopFile)
 {
 	int size;
-
 	SharedIspellDict *shdict = NULL;
 	SharedStopList	 *shstop = NULL;
 
-	IspellDict *dict;
-	StopList	stoplist;
-
 	/* DICTIONARY + AFFIXES */
 
 	/* TODO This should probably check that the filenames are not NULL, and maybe that
@@ -319,6 +315,8 @@ init_shared_dict(DictInfo *info, char *dictFile, char *affFile, char *stopFile)
 	/* load the dictionary (word list) if not yet defined */
 	if (shdict == NULL)
 	{
+		IspellDict *dict;
+
 		dict = (IspellDict *) palloc0(sizeof(IspellDict));
 
 		NIStartBuild(dict);
@@ -389,6 +387,8 @@ init_shared_dict(DictInfo *info, char *dictFile, char *affFile, char *stopFile)
 		/* load the stopwords if not yet defined */
 		if (shstop == NULL)
 		{
+			StopList	stoplist;
+
 			readstoplist(stopFile, &stoplist, lowerstr);
 
 			size = sizeStopList(&stoplist, stopFile);
@@ -418,6 +418,9 @@ init_shared_dict(DictInfo *info, char *dictFile, char *affFile, char *stopFile)
 		memcpy(info->stopFile, stopFile, strlen(stopFile) + 1);
 	else
 		memset(info->stopFile, 0, sizeof(info->stopFile));
+
+	/* save current context as long-lived */
+	info->saveCntx = CurrentMemoryContext;
 }
 
 Datum dispell_init(PG_FUNCTION_ARGS);
@@ -504,6 +507,9 @@ dispell_mem_used(PG_FUNCTION_ARGS)
  * The StopWords parameter is optional, the two other are required.
  *
  * If any of the filenames are incorrect, the call to init_shared_dict will fail.
+ *
+ * Do not call it directly - it saves current memory context as long-lived
+ * context.
  */
 Datum
 dispell_init(PG_FUNCTION_ARGS)
@@ -605,11 +611,27 @@ dispell_lexize(PG_FUNCTION_ARGS)
 	/* do we need to reinit the dictionary? was the dict reset since the lookup */
 	if (timestamp_cmp_internal(info->lookup, segment_info->lastReset) < 0)
 	{
+		DictInfo		saveInfo = *info;
+		MemoryContext	ctx;
+
 		/* relock in exclusive mode */
 		LWLockRelease(segment_info->lock);
 		LWLockAcquire(segment_info->lock, LW_EXCLUSIVE);
 
-		init_shared_dict(info, info->dictFile, info->affixFile, info->stopFile);
+		/*
+		 * info is allocated in info->saveCntx, so that's why we use a copy of
+		 * info here
+		 */
+
+		MemoryContextResetAndDeleteChildren(saveInfo.saveCntx);
+		ctx = MemoryContextSwitchTo(saveInfo.saveCntx);
+
+		info = palloc0(sizeof(*info));
+
+		init_shared_dict(info, saveInfo.dictFile,
+						 saveInfo.affixFile, saveInfo.stopFile);
+
+		MemoryContextSwitchTo(ctx);
 	}
 
 	res = NINormalizeWord(&(info->dict), txt);

contrib/shared_ispell/src/shared_ispell.h

@@ -2,6 +2,7 @@
 #define __SHARED_ISPELL_H__
 
 #include "storage/lwlock.h"
+#include "utils/memutils.h"
 #include "utils/timestamp.h"
 #include "tsearch/dicts/spell.h"
 #include "tsearch/ts_public.h"
@@ -66,6 +67,9 @@ typedef struct DictInfo
 	SharedIspellDict   *shdict;
 	IspellDict			dict;
 	SharedStopList	   *shstop;
+
+	/* MemoryContext of dict local content */
+	MemoryContext		saveCntx;
 } DictInfo;
 
-#endif
+#endif