Correct several behavior descriptions in comments.

Reuse cautionary language from src/test/ssl/README in
src/test/kerberos/README.  SLRUs have had access to six-character
segments names since commit 73c986adde5d73a5e2555da9b5c8facedb146dcd,
and recovery stopped calling HeapTupleHeaderAdvanceLatestRemovedXid() in
commit 558a9165e081d1936573e5a7d576f5febd7fb55a.  The other corrections
are more self-evident.

1 files changed, 4 insertions, 7 deletions

diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 4c1286eb988..774b26fd2c4 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -302,13 +302,10 @@ static SlruCtlData NotifyCtlData;
 #define QUEUE_FULL_WARN_INTERVAL	5000	/* warn at most once every 5s */
 
 /*
- * slru.c currently assumes that all filenames are four characters of hex
- * digits. That means that we can use segments 0000 through FFFF.
- * Each segment contains SLRU_PAGES_PER_SEGMENT pages which gives us
- * the pages from 0 to SLRU_PAGES_PER_SEGMENT * 0x10000 - 1.
- *
- * It's of course possible to enhance slru.c, but this gives us so much
- * space already that it doesn't seem worth the trouble.
+ * Use segments 0000 through FFFF.  Each contains SLRU_PAGES_PER_SEGMENT pages
+ * which gives us the pages from 0 to SLRU_PAGES_PER_SEGMENT * 0x10000 - 1.
+ * We could use as many segments as SlruScanDirectory() allows, but this gives
+ * us so much space already that it doesn't seem worth the trouble.
  *
  * The most data we can have in the queue at a time is QUEUE_MAX_PAGE/2
  * pages, because more than that would confuse slru.c into thinking there