On 08.08.24 19:42, Robert Haas wrote:
I'm thinking pg_upgrade could have a mode where it adds the
checksum during the upgrade as it copies the files (essentially a subset
of pg_checksums). I think that would be useful for that middle tier of
users who just want a good default experience.
That would be very nice.
Here is a demo patch for that. It turned out to be quite simple.
I wrote above about a separate mode for that (like
--copy-and-make-adjustments), but it was just as easy to stick it into
the existing --copy mode.
It would be useful to check what the performance overhead of this is
versus a copy that does not have to make adjustments. I expect it's
very little.
A drawback is that as written this does not work on Windows, because
Windows uses a different code path in copyFile(). I don't know the
reasons for that. But it would need to be figured out.
From 306c827c876378ddc128b030b8838a8e811743f2 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Thu, 15 Aug 2024 08:27:54 +0200
Subject: [PATCH v0] pg_upgrade support for upgrading to checksums enabled
---
src/bin/pg_upgrade/controldata.c | 17 +++++------------
src/bin/pg_upgrade/file.c | 21 ++++++++++++++++++++-
src/bin/pg_upgrade/pg_upgrade.h | 3 ++-
src/bin/pg_upgrade/relfilenumber.c | 2 +-
4 files changed, 28 insertions(+), 15 deletions(-)
diff --git a/src/bin/pg_upgrade/controldata.c b/src/bin/pg_upgrade/controldata.c
index 854c6887a23..16d0b84b337 100644
--- a/src/bin/pg_upgrade/controldata.c
+++ b/src/bin/pg_upgrade/controldata.c
@@ -693,18 +693,11 @@ check_control_data(ControlData *oldctrl,
* check_for_isn_and_int8_passing_mismatch().
*/
- /*
- * We might eventually allow upgrades from checksum to no-checksum
- * clusters.
- */
- if (oldctrl->data_checksum_version == 0 &&
- newctrl->data_checksum_version != 0)
- pg_fatal("old cluster does not use data checksums but the new
one does");
- else if (oldctrl->data_checksum_version != 0 &&
- newctrl->data_checksum_version == 0)
- pg_fatal("old cluster uses data checksums but the new one does
not");
- else if (oldctrl->data_checksum_version !=
newctrl->data_checksum_version)
- pg_fatal("old and new cluster pg_controldata checksum versions
do not match");
+ if (user_opts.transfer_mode != TRANSFER_MODE_COPY)
+ {
+ if (oldctrl->data_checksum_version !=
newctrl->data_checksum_version)
+ pg_fatal("when upgrading between clusters with
different data checksum settings, transfer mode --copy must be used");
+ }
}
diff --git a/src/bin/pg_upgrade/file.c b/src/bin/pg_upgrade/file.c
index 73932504cae..cef33b8f6eb 100644
--- a/src/bin/pg_upgrade/file.c
+++ b/src/bin/pg_upgrade/file.c
@@ -80,12 +80,14 @@ cloneFile(const char *src, const char *dst,
*/
void
copyFile(const char *src, const char *dst,
- const char *schemaName, const char *relName)
+ const char *schemaName, const char *relName,
+ int segno)
{
#ifndef WIN32
int src_fd;
int dest_fd;
char *buffer;
+ BlockNumber blocknum;
if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
pg_fatal("error while copying relation \"%s.%s\": could not
open file \"%s\": %m",
@@ -101,6 +103,8 @@ copyFile(const char *src, const char *dst,
buffer = (char *) pg_malloc(COPY_BUF_SIZE);
+ blocknum = segno * old_cluster.controldata.largesz;
+
/* perform data copying i.e read src source, write to destination */
while (true)
{
@@ -113,6 +117,19 @@ copyFile(const char *src, const char *dst,
if (nbytes == 0)
break;
+ if (new_cluster.controldata.data_checksum_version == 1)
+ {
+ for (int i = 0; i < 50 && i * BLCKSZ < nbytes; i++)
+ {
+ uint16 csum;
+ char *block = buffer + i * BLCKSZ;
+ PageHeader header = (PageHeader) block;
+
+ csum = pg_checksum_page(block, blocknum + i);
+ header->pd_checksum = csum;
+ }
+ }
+
errno = 0;
if (write(dest_fd, buffer, nbytes) != nbytes)
{
@@ -122,6 +139,8 @@ copyFile(const char *src, const char *dst,
pg_fatal("error while copying relation \"%s.%s\": could
not write file \"%s\": %m",
schemaName, relName, dst);
}
+
+ blocknum += 50;
}
pg_free(buffer);
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index cdb6e2b7597..c6a4ade53a7 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -404,7 +404,8 @@ bool pid_lock_file_exists(const char
*datadir);
void cloneFile(const char *src, const char *dst,
const char *schemaName, const char
*relName);
void copyFile(const char *src, const char *dst,
- const char *schemaName, const char
*relName);
+ const char *schemaName, const char
*relName,
+ int segno);
void copyFileByRange(const char *src, const char *dst,
const char *schemaName,
const char *relName);
void linkFile(const char *src, const char *dst,
diff --git a/src/bin/pg_upgrade/relfilenumber.c
b/src/bin/pg_upgrade/relfilenumber.c
index 1d3054d78bd..2ae69d71159 100644
--- a/src/bin/pg_upgrade/relfilenumber.c
+++ b/src/bin/pg_upgrade/relfilenumber.c
@@ -250,7 +250,7 @@ transfer_relfile(FileNameMap *map, const char *type_suffix,
bool vm_must_add_fro
case TRANSFER_MODE_COPY:
pg_log(PG_VERBOSE, "copying \"%s\" to
\"%s\"",
old_file, new_file);
- copyFile(old_file, new_file,
map->nspname, map->relname);
+ copyFile(old_file, new_file,
map->nspname, map->relname, segno);
break;
case TRANSFER_MODE_COPY_FILE_RANGE:
pg_log(PG_VERBOSE, "copying \"%s\" to
\"%s\" with copy_file_range",
--
2.46.0
