amcheck: Reword some messages and fix an alignment problem.

We don't need to mention the attribute number in these messages, because
there's a dedicated column for that, but we should mention the toast
value ID, because that's really useful for any follow-up troubleshooting
the user wants to do. This also rewords some of the messages to hopefully
read a little better.

Also, use VARATT_EXTERNAL_GET_POINTER in case we're accessing a TOAST
pointer that isn't aligned on a platform that's fussy about alignment,
so that we don't crash while corruption-checking the user's data.

Mark Dilger, reviewed by me.

Discussion: http://postgr.es/m/7D3B9BF6-50D0-4C30-8506-1C1851C7F96F@enterprisedb.com

diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index e8aa0d68d4eeda97a8ff2bb2691a6e8b7677369a..13f420d9adad6f359acd68896c16bc39ae009ed0 100644 (file)
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -1179,7 +1179,8 @@ check_toast_tuple(HeapTuple toasttup, HeapCheckContext *ctx,
        if (isnull)
        {
                report_toast_corruption(ctx, ta,
-                                                 pstrdup("toast chunk sequence number is null"));
+                                                               psprintf("toast value %u has toast chunk with null sequence number",
+                                                                                ta->toast_pointer.va_valueid));
                return;
        }
        chunk = DatumGetPointer(fastgetattr(toasttup, 3,
@@ -1187,7 +1188,8 @@ check_toast_tuple(HeapTuple toasttup, HeapCheckContext *ctx,
        if (isnull)
        {
                report_toast_corruption(ctx, ta,
-                                                 pstrdup("toast chunk data is null"));
+                                                               psprintf("toast value %u chunk %d has null data",
+                                                                                ta->toast_pointer.va_valueid, chunkno));
                return;
        }
        if (!VARATT_IS_EXTENDED(chunk))
@@ -1205,8 +1207,9 @@ check_toast_tuple(HeapTuple toasttup, HeapCheckContext *ctx,
                uint32          header = ((varattrib_4b *) chunk)->va_4byte.va_header;
 
                report_toast_corruption(ctx, ta,
-                                                 psprintf("corrupt extended toast chunk has invalid varlena header: %0x (sequence number %d)",
-                                                                  header, curchunk));
+                                                               psprintf("toast value %u chunk %d has invalid varlena header %0x",
+                                                                                ta->toast_pointer.va_valueid,
+                                                                                chunkno, header));
                return;
        }
 
@@ -1216,15 +1219,17 @@ check_toast_tuple(HeapTuple toasttup, HeapCheckContext *ctx,
        if (curchunk != chunkno)
        {
                report_toast_corruption(ctx, ta,
-                                                 psprintf("toast chunk sequence number %u does not match the expected sequence number %u",
-                                                                  curchunk, chunkno));
+                                                               psprintf("toast value %u chunk %d has sequence number %d, but expected sequence number %d",
+                                                                                ta->toast_pointer.va_valueid,
+                                                                                chunkno, curchunk, chunkno));
                return;
        }
-       if (curchunk > endchunk)
+       if (chunkno > endchunk)
        {
                report_toast_corruption(ctx, ta,
-                                                 psprintf("toast chunk sequence number %u exceeds the end chunk sequence number %u",
-                                                                  curchunk, endchunk));
+                                                               psprintf("toast value %u chunk %d follows last expected chunk %d",
+                                                                                ta->toast_pointer.va_valueid,
+                                                                                chunkno, endchunk));
                return;
        }
 
@@ -1233,8 +1238,9 @@ check_toast_tuple(HeapTuple toasttup, HeapCheckContext *ctx,
 
        if (chunksize != expected_size)
                report_toast_corruption(ctx, ta,
-                                                 psprintf("toast chunk size %u differs from the expected size %u",
-                                                                  chunksize, expected_size));
+                                                               psprintf("toast value %u chunk %d has size %u, but expected size %u",
+                                                                                ta->toast_pointer.va_valueid,
+                                                                                chunkno, chunksize, expected_size));
 }
 
 /*
@@ -1265,6 +1271,7 @@ check_tuple_attribute(HeapCheckContext *ctx)
        char       *tp;                         /* pointer to the tuple data */
        uint16          infomask;
        Form_pg_attribute thisatt;
+       struct varatt_external toast_pointer;
 
        infomask = ctx->tuphdr->t_infomask;
        thisatt = TupleDescAttr(RelationGetDescr(ctx->rel), ctx->attnum);
@@ -1274,8 +1281,7 @@ check_tuple_attribute(HeapCheckContext *ctx)
        if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
        {
                report_corruption(ctx,
-                                                 psprintf("attribute %u with length %u starts at offset %u beyond total tuple length %u",
-                                                                  ctx->attnum,
+                                                 psprintf("attribute with length %u starts at offset %u beyond total tuple length %u",
                                                                   thisatt->attlen,
                                                                   ctx->tuphdr->t_hoff + ctx->offset,
                                                                   ctx->lp_len));
@@ -1295,8 +1301,7 @@ check_tuple_attribute(HeapCheckContext *ctx)
                if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
                {
                        report_corruption(ctx,
-                                                         psprintf("attribute %u with length %u ends at offset %u beyond total tuple length %u",
-                                                                          ctx->attnum,
+                                                         psprintf("attribute with length %u ends at offset %u beyond total tuple length %u",
                                                                           thisatt->attlen,
                                                                           ctx->tuphdr->t_hoff + ctx->offset,
                                                                           ctx->lp_len));
@@ -1328,8 +1333,7 @@ check_tuple_attribute(HeapCheckContext *ctx)
                if (va_tag != VARTAG_ONDISK)
                {
                        report_corruption(ctx,
-                                                         psprintf("toasted attribute %u has unexpected TOAST tag %u",
-                                                                          ctx->attnum,
+                                                         psprintf("toasted attribute has unexpected TOAST tag %u",
                                                                           va_tag));
                        /* We can't know where the next attribute begins */
                        return false;
@@ -1343,8 +1347,7 @@ check_tuple_attribute(HeapCheckContext *ctx)
        if (ctx->tuphdr->t_hoff + ctx->offset > ctx->lp_len)
        {
                report_corruption(ctx,
-                                                 psprintf("attribute %u with length %u ends at offset %u beyond total tuple length %u",
-                                                                  ctx->attnum,
+                                                 psprintf("attribute with length %u ends at offset %u beyond total tuple length %u",
                                                                   thisatt->attlen,
                                                                   ctx->tuphdr->t_hoff + ctx->offset,
                                                                   ctx->lp_len));
@@ -1371,12 +1374,17 @@ check_tuple_attribute(HeapCheckContext *ctx)
 
        /* It is external, and we're looking at a page on disk */
 
+       /*
+        * Must copy attr into toast_pointer for alignment considerations
+        */
+       VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
+
        /* The tuple header better claim to contain toasted values */
        if (!(infomask & HEAP_HASEXTERNAL))
        {
                report_corruption(ctx,
-                                                 psprintf("attribute %u is external but tuple header flag HEAP_HASEXTERNAL not set",
-                                                                  ctx->attnum));
+                                                 psprintf("toast value %u is external but tuple header flag HEAP_HASEXTERNAL not set",
+                                                                  toast_pointer.va_valueid));
                return true;
        }
 
@@ -1384,8 +1392,8 @@ check_tuple_attribute(HeapCheckContext *ctx)
        if (!ctx->rel->rd_rel->reltoastrelid)
        {
                report_corruption(ctx,
-                                                 psprintf("attribute %u is external but relation has no toast relation",
-                                                                  ctx->attnum));
+                                                 psprintf("toast value %u is external but relation has no toast relation",
+                                                                  toast_pointer.va_valueid));
                return true;
        }
 
@@ -1464,12 +1472,13 @@ check_toasted_attribute(HeapCheckContext *ctx, ToastedAttribute *ta)
 
        if (!found_toasttup)
                report_toast_corruption(ctx, ta,
-                                                               psprintf("toasted value for attribute %u missing from toast table",
-                                                                                ta->attnum));
+                                                               psprintf("toast value %u not found in toast table",
+                                                                                ta->toast_pointer.va_valueid));
        else if (chunkno != (endchunk + 1))
                report_toast_corruption(ctx, ta,
-                                                               psprintf("final toast chunk number %u differs from expected value %u",
-                                                                                chunkno, (endchunk + 1)));
+                                                               psprintf("toast value %u was expected to end at chunk %u, but ended at chunk %u",
+                                                                                ta->toast_pointer.va_valueid,
+                                                                                (endchunk + 1), chunkno));
 }
 
 /*

diff --git a/src/bin/pg_amcheck/t/004_verify_heapam.pl b/src/bin/pg_amcheck/t/004_verify_heapam.pl
index 2171d236a7a0f36a467e69c2322d42a2be468ee1..3c1277adf3e1cb39b6e2f3f520db5c0bf0ce6be5 100644 (file)
--- a/src/bin/pg_amcheck/t/004_verify_heapam.pl
+++ b/src/bin/pg_amcheck/t/004_verify_heapam.pl
@@ -480,7 +480,7 @@ for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
 
                $header = header(0, $offnum, 1);
                push @expected,
-                       qr/${header}attribute \d+ with length \d+ ends at offset \d+ beyond total tuple length \d+/;
+                       qr/${header}attribute with length \d+ ends at offset \d+ beyond total tuple length \d+/;
        }
        elsif ($offnum == 13)
        {
@@ -489,7 +489,7 @@ for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
 
                $header = header(0, $offnum, 2);
                push @expected,
-                       qr/${header}toasted value for attribute 2 missing from toast table/;
+                       qr/${header}toast value \d+ not found in toast table/;
        }
        elsif ($offnum == 14)
        {