Hi,
A couple times when investigating data corruption issues, the last time just
yesterday in [1], I needed to see the offsets affected by PRUNE and VACUUM
records. As that's probably not just me, I think we should make that change
in-tree.
The attached patch adds details to XLOG_HEAP2_PRUNE, XLOG_HEAP2_VACUUM,
XLOG_HEAP2_FREEZE_PAGE.
The biggest issue I have with the patch is that it's very hard to figure out
what punctuation to use where ;). The existing code is very inconsistent.
I chose to include infomask[2] for the different freeze plans mainly because
it looks odd to see different plans without a visible reason. But I'm not sure
that's the right choice.
Greetings,
Andres Freund
[1]
https://postgr.es/m/CANtu0ojby3eBdMXfs4QmS%2BK1avBc7NcRq_Ot5bnzrbwM%2BuQ55w%40mail.gmail.com
>From 2668f69edc5345a45b850eb4f33321f8bc18cb6e Mon Sep 17 00:00:00 2001
From: Andres Freund <and...@anarazel.de>
Date: Mon, 9 Jan 2023 13:49:09 -0800
Subject: [PATCH v3] heapdesc: Include information about offset arrays
---
src/backend/access/rmgrdesc/heapdesc.c | 94 ++++++++++++++++++++++++++
1 file changed, 94 insertions(+)
diff --git a/src/backend/access/rmgrdesc/heapdesc.c b/src/backend/access/rmgrdesc/heapdesc.c
index 628f7e82156..f1c4a0e4c64 100644
--- a/src/backend/access/rmgrdesc/heapdesc.c
+++ b/src/backend/access/rmgrdesc/heapdesc.c
@@ -114,6 +114,37 @@ heap_desc(StringInfo buf, XLogReaderState *record)
appendStringInfo(buf, "off %u", xlrec->offnum);
}
}
+
+static void
+print_offset_array(StringInfo buf, const char *label, OffsetNumber *offsets, int count)
+{
+ if (count == 0)
+ return;
+ appendStringInfo(buf, "%s [", label);
+ for (int i = 0; i < count; i++)
+ {
+ if (i > 0)
+ appendStringInfoString(buf, ", ");
+ appendStringInfo(buf, "%u", offsets[i]);
+ }
+ appendStringInfoString(buf, "]");
+}
+
+static void
+print_redirect_array(StringInfo buf, const char *label, OffsetNumber *offsets, int count)
+{
+ if (count == 0)
+ return;
+ appendStringInfo(buf, "%s [", label);
+ for (int i = 0; i < count; i++)
+ {
+ if (i > 0)
+ appendStringInfoString(buf, ", ");
+ appendStringInfo(buf, "%u->%u", offsets[i * 2], offsets[i * 2 + 1]);
+ }
+ appendStringInfoString(buf, "]");
+}
+
void
heap2_desc(StringInfo buf, XLogReaderState *record)
{
@@ -129,12 +160,48 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
xlrec->snapshotConflictHorizon,
xlrec->nredirected,
xlrec->ndead);
+
+
+ if (!XLogRecHasBlockImage(record, 0))
+ {
+ OffsetNumber *end;
+ OffsetNumber *redirected;
+ OffsetNumber *nowdead;
+ OffsetNumber *nowunused;
+ int nredirected;
+ int nunused;
+ Size datalen;
+
+ redirected = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+ nredirected = xlrec->nredirected;
+ end = (OffsetNumber *) ((char *) redirected + datalen);
+ nowdead = redirected + (nredirected * 2);
+ nowunused = nowdead + xlrec->ndead;
+ nunused = (end - nowunused);
+ Assert(nunused >= 0);
+
+ appendStringInfo(buf, " nunused %u", nunused);
+ print_offset_array(buf, ", unused:", nowunused, nunused);
+ print_redirect_array(buf, ", redirected:", redirected, nredirected);
+ print_offset_array(buf, ", dead:", nowdead, xlrec->ndead);
+ }
}
else if (info == XLOG_HEAP2_VACUUM)
{
xl_heap_vacuum *xlrec = (xl_heap_vacuum *) rec;
appendStringInfo(buf, "nunused %u", xlrec->nunused);
+
+ if (!XLogRecHasBlockImage(record, 0))
+ {
+ OffsetNumber *nowunused;
+ Size datalen;
+
+ nowunused = (OffsetNumber *) XLogRecGetBlockData(record, 0, &datalen);
+
+ print_offset_array(buf, " unused:", nowunused, xlrec->nunused);
+ }
}
else if (info == XLOG_HEAP2_FREEZE_PAGE)
{
@@ -142,6 +209,30 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
appendStringInfo(buf, "snapshotConflictHorizon %u nplans %u",
xlrec->snapshotConflictHorizon, xlrec->nplans);
+
+ if (!XLogRecHasBlockImage(record, 0))
+ {
+ OffsetNumber *offsets;
+ xl_heap_freeze_plan *plans;
+ int curoff = 0;
+
+ plans = (xl_heap_freeze_plan *) XLogRecGetBlockData(record, 0, NULL);
+ offsets = (OffsetNumber *) ((char *) plans +
+ (xlrec->nplans *
+ sizeof(xl_heap_freeze_plan)));
+
+ for (int p = 0; p < xlrec->nplans; p++)
+ {
+ xl_heap_freeze_plan plan;
+
+ memcpy(&plan, &plans[p], sizeof(xl_heap_freeze_plan));
+
+ appendStringInfo(buf, "; plan #%d: xmax %u infomask %u infomask2 %u",
+ p, plan.xmax, plan.t_infomask, plan.t_infomask2);
+ print_offset_array(buf, ", offsets", offsets + curoff, plan.ntuples);
+ curoff += plan.ntuples;
+ }
+ }
}
else if (info == XLOG_HEAP2_VISIBLE)
{
@@ -153,9 +244,12 @@ heap2_desc(StringInfo buf, XLogReaderState *record)
else if (info == XLOG_HEAP2_MULTI_INSERT)
{
xl_heap_multi_insert *xlrec = (xl_heap_multi_insert *) rec;
+ bool isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
appendStringInfo(buf, "%d tuples flags 0x%02X", xlrec->ntuples,
xlrec->flags);
+ if (!XLogRecHasBlockImage(record, 0) && !isinit)
+ print_offset_array(buf, " offsets", xlrec->offsets, xlrec->ntuples);
}
else if (info == XLOG_HEAP2_LOCK_UPDATED)
{
--
2.38.0
