Cosmetic fixes for hash index write-ahead logging.

robertmhaas · robertmhaas · commit f7b711c8bcef · 2017-03-15T07:22:49.000-04:00
Amit Kapila. One of these was reported by Tom Lane. Discussion: http://postgr.es/m/5515.1489514099@sss.pgh.pa.us
diff --git a/src/backend/access/hash/README b/src/backend/access/hash/README
@@ -365,9 +365,6 @@ try to split the bucket again until the prior split is finished.  In other
 words, a bucket can be in the middle of being split for some time, but it can't
 be in the middle of two splits at the same time.
 
-Although we can survive a failure to split a bucket, a crash is likely to
-corrupt the index, since hash indexes are not yet WAL-logged.
-
 The fourth operation is garbage collection (bulk deletion):
 
 	next bucket := 0
diff --git a/src/backend/access/hash/hashpage.c b/src/backend/access/hash/hashpage.c
@@ -975,7 +975,7 @@ _hash_expandtable(Relation rel, Buffer metabuf)
  * hash indexes sequentially anyway, that probably doesn't matter.
  *
  * XXX It's annoying that this code is executed with the metapage lock held.
- * We need to interlock against _hash_getovflpage() adding a new overflow page
+ * We need to interlock against _hash_addovflpage() adding a new overflow page
  * concurrently, but it'd likely be better to use LockRelationForExtension
  * for the purpose.  OTOH, adding a splitpoint is a very infrequent operation,
  * so it may not be worth worrying about.

Original file line number	Diff line number	Diff line change
`@@ -975,7 +975,7 @@ _hash_expandtable(Relation rel, Buffer metabuf)`
`975`	`975`	`* hash indexes sequentially anyway, that probably doesn't matter.`
`976`	`976`	`*`
`977`	`977`	`* XXX It's annoying that this code is executed with the metapage lock held.`
`978`		`- * We need to interlock against _hash_getovflpage() adding a new overflow page`
	`978`	`+ * We need to interlock against _hash_addovflpage() adding a new overflow page`
`979`	`979`	`* concurrently, but it'd likely be better to use LockRelationForExtension`
`980`	`980`	`* for the purpose. OTOH, adding a splitpoint is a very infrequent operation,`
`981`	`981`	`* so it may not be worth worrying about.`