Fixes for single-page hash index vacuum.

Clear LH_PAGE_HAS_DEAD_TUPLES during replay, similar to what gets done
for btree.  Update hashdesc.c for xl_hash_vacuum_one_page.

Oversights in commit 6977b8b7f4dfb40896ff5e2175cad7fdbda862eb spotted
by Amit Kapila.  Patch by Ashutosh Sharma.

Bump WAL version.  The original patch to make hash indexes write-ahead
logged probably should have done this, and the single page vacuuming
patch probably should have done it again, but better late than never.

Discussion: http://postgr.es/m/CAA4eK1Kd=mJ9xreovcsh0qMiAj-QqCphHVQ_Lfau1DR9oVjASQ@mail.gmail.com

diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index cfcec3475d420effd4eeb87051cb4e7618c4dca7..34cc08f12d2fcb39b3bb555bce359864e3e1c25f 100644 (file)
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -790,6 +790,7 @@ hashbucketcleanup(Relation rel, Bucket cur_bucket, Buffer bucket_buf,
                OffsetNumber deletable[MaxOffsetNumber];
                int                     ndeletable = 0;
                bool            retain_pin = false;
+               bool            clear_dead_marking = false;
 
                vacuum_delay_point();
 
@@ -877,11 +878,14 @@ hashbucketcleanup(Relation rel, Bucket cur_bucket, Buffer bucket_buf,
                        /*
                         * Let us mark the page as clean if vacuum removes the DEAD tuples
                         * from an index page. We do this by clearing LH_PAGE_HAS_DEAD_TUPLES
-                        * flag. Clearing this flag is just a hint; replay won't redo this.
+                        * flag.
                         */
                        if (tuples_removed && *tuples_removed > 0 &&
                                opaque->hasho_flag & LH_PAGE_HAS_DEAD_TUPLES)
+                       {
                                opaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
+                               clear_dead_marking = true;
+                       }
 
                        MarkBufferDirty(buf);
 
@@ -891,6 +895,7 @@ hashbucketcleanup(Relation rel, Bucket cur_bucket, Buffer bucket_buf,
                                xl_hash_delete xlrec;
                                XLogRecPtr      recptr;
 
+                               xlrec.clear_dead_marking = clear_dead_marking;
                                xlrec.is_primary_bucket_page = (buf == bucket_buf) ? true : false;
 
                                XLogBeginInsert();

diff --git a/src/backend/access/hash/hash_xlog.c b/src/backend/access/hash/hash_xlog.c
index 8647e8c6adca5cb9dfbda70d87f20c44cf5819b8..ac82092ab2492ca7081f2118077436cb16f975a9 100644 (file)
--- a/src/backend/access/hash/hash_xlog.c
+++ b/src/backend/access/hash/hash_xlog.c
@@ -859,6 +859,19 @@ hash_xlog_delete(XLogReaderState *record)
                                PageIndexMultiDelete(page, unused, unend - unused);
                }
 
+               /*
+                * Mark the page as not containing any LP_DEAD items only if
+                * clear_dead_marking flag is set to true. See comments in
+                * hashbucketcleanup() for details.
+                */
+               if (xldata->clear_dead_marking)
+               {
+                       HashPageOpaque pageopaque;
+
+                       pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+                       pageopaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
+               }
+
                PageSetLSN(page, lsn);
                MarkBufferDirty(deletebuf);
        }
@@ -1078,6 +1091,7 @@ hash_xlog_vacuum_one_page(XLogReaderState *record)
        Buffer metabuf;
        Page page;
        XLogRedoAction action;
+       HashPageOpaque pageopaque;
 
        xldata = (xl_hash_vacuum_one_page *) XLogRecGetData(record);
 
@@ -1126,6 +1140,13 @@ hash_xlog_vacuum_one_page(XLogReaderState *record)
                                PageIndexMultiDelete(page, unused, unend - unused);
                }
 
+               /*
+                * Mark the page as not containing any LP_DEAD items. See comments
+                * in _hash_vacuum_one_page() for details.
+                */
+               pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
+               pageopaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
+
                PageSetLSN(page, lsn);
                MarkBufferDirty(buffer);
        }

diff --git a/src/backend/access/hash/hashinsert.c b/src/backend/access/hash/hashinsert.c
index 8b6d0a0ff7821bbbe2717369e21f2108d06a9e65..8640e85a5c6b62960ebd4352c73e92a5bfbfbdfc 100644 (file)
--- a/src/backend/access/hash/hashinsert.c
+++ b/src/backend/access/hash/hashinsert.c
@@ -374,6 +374,14 @@ _hash_vacuum_one_page(Relation rel, Buffer metabuf, Buffer buf,
 
                PageIndexMultiDelete(page, deletable, ndeletable);
 
+               /*
+                * Mark the page as not containing any LP_DEAD items. This is not
+                * certainly true (there might be some that have recently been marked,
+                * but weren't included in our target-item list), but it will almost
+                * always be true and it doesn't seem worth an additional page scan
+                * to check it. Remember that LH_PAGE_HAS_DEAD_TUPLES is only a hint
+                * anyway.
+                */
                pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
                pageopaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
 

diff --git a/src/backend/access/rmgrdesc/hashdesc.c b/src/backend/access/rmgrdesc/hashdesc.c
index 5bd5c8dc0103cdf5902f32fd00bbd131d90529df..5f5f4a0255192d9cf11fc638acde9d7115af4ca7 100644 (file)
--- a/src/backend/access/rmgrdesc/hashdesc.c
+++ b/src/backend/access/rmgrdesc/hashdesc.c
@@ -96,7 +96,8 @@ hash_desc(StringInfo buf, XLogReaderState *record)
                        {
                                xl_hash_delete *xlrec = (xl_hash_delete *) rec;
 
-                               appendStringInfo(buf, "is_primary %c",
+                               appendStringInfo(buf, "clear_dead_marking %c, is_primary %c",
+                                                                xlrec->clear_dead_marking ? 'T' : 'F',
                                                                 xlrec->is_primary_bucket_page ? 'T' : 'F');
                                break;
                        }
@@ -104,6 +105,14 @@ hash_desc(StringInfo buf, XLogReaderState *record)
                        {
                                xl_hash_update_meta_page *xlrec = (xl_hash_update_meta_page *) rec;
 
+                               appendStringInfo(buf, "ntuples %g",
+                                                                xlrec->ntuples);
+                               break;
+                       }
+               case XLOG_HASH_VACUUM_ONE_PAGE:
+                       {
+                               xl_hash_vacuum_one_page *xlrec = (xl_hash_vacuum_one_page *) rec;
+
                                appendStringInfo(buf, "ntuples %g",
                                                                 xlrec->ntuples);
                                break;

diff --git a/src/include/access/hash_xlog.h b/src/include/access/hash_xlog.h
index dfd923781997e4586b90c492c2dff700d79fc40c..2e64cfa3eafc477bc64550b19c74a81e7731b98e 100644 (file)
--- a/src/include/access/hash_xlog.h
+++ b/src/include/access/hash_xlog.h
@@ -197,6 +197,8 @@ typedef struct xl_hash_squeeze_page
  */
 typedef struct xl_hash_delete
 {
+       bool            clear_dead_marking;             /* TRUE if this operation clears
+                                                                                * LH_PAGE_HAS_DEAD_TUPLES flag */
        bool            is_primary_bucket_page; /* TRUE if the operation is for
                                                                                 * primary bucket page */
 }      xl_hash_delete;

diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index b8b15f18752cf460c559bbcb63bf15825febb1a7..7957cab98c62731b64d0dbf6f800589594aa171d 100644 (file)
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -31,7 +31,7 @@
 /*
  * Each page of XLOG file has a header like this:
  */
-#define XLOG_PAGE_MAGIC 0xD095 /* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD096 /* can be used as WAL version indicator */
 
 typedef struct XLogPageHeaderData
 {