Subject: [PATCH v2 2/4] pg_upgrade: bump minimum supported version to v10

From: Nathan Bossart <[email-masked]>
Date: Fri, 17 Apr 2026 11:20:18 -0700

---
 doc/src/sgml/ref/pgupgrade.sgml        |   2 +-
 src/bin/pg_upgrade/check.c             | 157 +----------------------
 src/bin/pg_upgrade/controldata.c       |  12 +-
 src/bin/pg_upgrade/exec.c              |  23 ----
 src/bin/pg_upgrade/file.c              | 164 -------------------------
 src/bin/pg_upgrade/multixact_rewrite.c |  11 +-
 src/bin/pg_upgrade/pg_upgrade.c        |  31 +----
 src/bin/pg_upgrade/pg_upgrade.h        |  29 -----
 src/bin/pg_upgrade/relfilenumber.c     |  37 +-----
 src/bin/pg_upgrade/version.c           | 127 -------------------
 10 files changed, 16 insertions(+), 577 deletions(-)

diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index 38ca09b423c..c4ed75211db 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -67,7 +67,7 @@ PostgreSQL documentation
  </para>
 
   <para>
-   <application>pg_upgrade</application> supports upgrades from 9.2.X and later to the current
+   <application>pg_upgrade</application> supports upgrades from 10.X and later to the current
    major release of <productname>PostgreSQL</productname>, including snapshot and beta releases.
   </para>
 
diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index 5a7afe62eab..0813cef2729 100644
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -28,7 +28,6 @@ static void check_for_incompatible_polymorphics(ClusterInfo *cluster);
 static void check_for_tables_with_oids(ClusterInfo *cluster);
 static void check_for_not_null_inheritance(ClusterInfo *cluster);
 static void check_for_gist_inet_ops(ClusterInfo *cluster);
-static void check_for_pg_role_prefix(ClusterInfo *cluster);
 static void check_for_new_tablespace_dir(void);
 static void check_for_user_defined_encoding_conversions(ClusterInfo *cluster);
 static void check_for_unicode_update(ClusterInfo *cluster);
@@ -128,26 +127,6 @@ static DataTypesUsageChecks data_types_usage_checks[] =
 		.threshold_version = ALL_VERSIONS
 	},
 
-	/*
-	 * 9.3 -> 9.4 Fully implement the 'line' data type in 9.4, which
-	 * previously returned "not enabled" by default and was only functionally
-	 * enabled with a compile-time switch; as of 9.4 "line" has a different
-	 * on-disk representation format.
-	 */
-	{
-		.status = gettext_noop("Checking for incompatible \"line\" data type"),
-		.report_filename = "tables_using_line.txt",
-		.base_query =
-		"SELECT 'pg_catalog.line'::pg_catalog.regtype AS oid",
-		.report_text =
-		gettext_noop("Your installation contains the \"line\" data type in user tables.\n"
-					 "This data type changed its internal and input/output format\n"
-					 "between your old and new versions so this\n"
-					 "cluster cannot currently be upgraded.  You can\n"
-					 "drop the problem columns and restart the upgrade.\n"),
-		.threshold_version = 903
-	},
-
 	/*
 	 * pg_upgrade only preserves these system values: pg_class.oid pg_type.oid
 	 * pg_enum.oid
@@ -209,30 +188,6 @@ static DataTypesUsageChecks data_types_usage_checks[] =
 		.threshold_version = 1500
 	},
 
-	/*
-	 * It's no longer allowed to create tables or views with "unknown"-type
-	 * columns.  We do not complain about views with such columns, because
-	 * they should get silently converted to "text" columns during the DDL
-	 * dump and reload; it seems unlikely to be worth making users do that by
-	 * hand.  However, if there's a table with such a column, the DDL reload
-	 * will fail, so we should pre-detect that rather than failing
-	 * mid-upgrade.  Worse, if there's a matview with such a column, the DDL
-	 * reload will silently change it to "text" which won't match the on-disk
-	 * storage (which is like "cstring").  So we *must* reject that.
-	 */
-	{
-		.status = gettext_noop("Checking for invalid \"unknown\" user columns"),
-		.report_filename = "tables_using_unknown.txt",
-		.base_query =
-		"SELECT 'pg_catalog.unknown'::pg_catalog.regtype AS oid",
-		.report_text =
-		gettext_noop("Your installation contains the \"unknown\" data type in user tables.\n"
-					 "This data type is no longer allowed in tables, so this cluster\n"
-					 "cannot currently be upgraded.  You can drop the problem columns\n"
-					 "and restart the upgrade.\n"),
-		.threshold_version = 906
-	},
-
 	/*
 	 * PG 12 changed the 'sql_identifier' type storage to be based on name,
 	 * not varchar, which breaks on-disk format for existing data. So we need
@@ -255,23 +210,6 @@ static DataTypesUsageChecks data_types_usage_checks[] =
 		.threshold_version = 1100
 	},
 
-	/*
-	 * JSONB changed its storage format during 9.4 beta, so check for it.
-	 */
-	{
-		.status = gettext_noop("Checking for incompatible \"jsonb\" data type in user tables"),
-		.report_filename = "tables_using_jsonb.txt",
-		.base_query =
-		"SELECT 'pg_catalog.jsonb'::pg_catalog.regtype AS oid",
-		.report_text =
-		gettext_noop("Your installation contains the \"jsonb\" data type in user tables.\n"
-					 "The internal format of \"jsonb\" changed during 9.4 beta so this\n"
-					 "cluster cannot currently be upgraded.  You can drop the problem \n"
-					 "columns and restart the upgrade.\n"),
-		.threshold_version = MANUAL_CHECK,
-		.version_hook = jsonb_9_4_check_applicable
-	},
-
 	/*
 	 * PG 12 removed types abstime, reltime, tinterval.
 	 */
@@ -712,20 +650,6 @@ check_and_dump_old_cluster(void)
 	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 1800)
 		check_for_gist_inet_ops(&old_cluster);
 
-	/*
-	 * Pre-PG 10 allowed tables with 'unknown' type columns and non WAL logged
-	 * hash indexes
-	 */
-	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 906)
-	{
-		if (user_opts.check)
-			old_9_6_invalidate_hash_indexes(&old_cluster, true);
-	}
-
-	/* 9.5 and below should not have roles starting with pg_ */
-	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 905)
-		check_for_pg_role_prefix(&old_cluster);
-
 	/*
 	 * While not a check option, we do this now because this is the only time
 	 * the old server is running.
@@ -772,20 +696,6 @@ check_new_cluster(void)
 			 * system boundaries.
 			 */
 			check_hard_link(TRANSFER_MODE_SWAP);
-
-			/*
-			 * There are a few known issues with using --swap to upgrade from
-			 * versions older than 10.  For example, the sequence tuple format
-			 * changed in v10, and the visibility map format changed in 9.6.
-			 * While such problems are not insurmountable (and we may have to
-			 * deal with similar problems in the future, anyway), it doesn't
-			 * seem worth the effort to support swap mode for upgrades from
-			 * long-unsupported versions.
-			 */
-			if (GET_MAJOR_VERSION(old_cluster.major_version) < 1000)
-				pg_fatal("Swap mode can only upgrade clusters from PostgreSQL version %s and later.",
-						 "10");
-
 			break;
 	}
 
@@ -831,10 +741,6 @@ issue_warnings_and_set_wal_level(void)
 	 */
 	start_postmaster(&new_cluster, true);
 
-	/* Reindex hash indexes for old < 10.0 */
-	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 906)
-		old_9_6_invalidate_hash_indexes(&new_cluster, false);
-
 	report_extension_updates(&new_cluster);
 
 	stop_postmaster(false);
@@ -892,9 +798,9 @@ check_cluster_versions(void)
 	 * upgrades
 	 */
 
-	if (GET_MAJOR_VERSION(old_cluster.major_version) < 902)
+	if (GET_MAJOR_VERSION(old_cluster.major_version) < 10)
 		pg_fatal("This utility can only upgrade from PostgreSQL version %s and later.",
-				 "9.2");
+				 "10");
 
 	/* Only current PG version is supported as a target */
 	if (GET_MAJOR_VERSION(new_cluster.major_version) != GET_MAJOR_VERSION(PG_VERSION_NUM))
@@ -1569,12 +1475,10 @@ check_for_incompatible_polymorphics(ClusterInfo *cluster)
 						 ", 'array_cat(anyarray,anyarray)'"
 						 ", 'array_prepend(anyelement,anyarray)'");
 
-	if (GET_MAJOR_VERSION(cluster->major_version) >= 903)
 		appendPQExpBufferStr(&old_polymorphics,
 							 ", 'array_remove(anyarray,anyelement)'"
 							 ", 'array_replace(anyarray,anyelement,anyelement)'");
 
-	if (GET_MAJOR_VERSION(cluster->major_version) >= 905)
 		appendPQExpBufferStr(&old_polymorphics,
 							 ", 'array_position(anyarray,anyelement)'"
 							 ", 'array_position(anyarray,anyelement,integer)'"
@@ -1870,63 +1774,6 @@ check_for_gist_inet_ops(ClusterInfo *cluster)
 		check_ok();
 }
 
-/*
- * check_for_pg_role_prefix()
- *
- *	Versions older than 9.6 should not have any pg_* roles
- */
-static void
-check_for_pg_role_prefix(ClusterInfo *cluster)
-{
-	PGresult   *res;
-	PGconn	   *conn = connectToServer(cluster, "template1");
-	int			ntups;
-	int			i_roloid;
-	int			i_rolname;
-	FILE	   *script = NULL;
-	char		output_path[MAXPGPATH];
-
-	prep_status("Checking for roles starting with \"pg_\"");
-
-	snprintf(output_path, sizeof(output_path), "%s/%s",
-			 log_opts.basedir,
-			 "pg_role_prefix.txt");
-
-	res = executeQueryOrDie(conn,
-							"SELECT oid AS roloid, rolname "
-							"FROM pg_catalog.pg_roles "
-							"WHERE rolname ~ '^pg_'");
-
-	ntups = PQntuples(res);
-	i_roloid = PQfnumber(res, "roloid");
-	i_rolname = PQfnumber(res, "rolname");
-	for (int rowno = 0; rowno < ntups; rowno++)
-	{
-		if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-			pg_fatal("could not open file \"%s\": %m", output_path);
-		fprintf(script, "%s (oid=%s)\n",
-				PQgetvalue(res, rowno, i_rolname),
-				PQgetvalue(res, rowno, i_roloid));
-	}
-
-	PQclear(res);
-
-	PQfinish(conn);
-
-	if (script)
-	{
-		fclose(script);
-		pg_log(PG_REPORT, "fatal");
-		pg_fatal("Your installation contains roles starting with \"pg_\".\n"
-				 "\"pg_\" is a reserved prefix for system roles.  The cluster\n"
-				 "cannot be upgraded until these roles are renamed.\n"
-				 "A list of roles starting with \"pg_\" is in the file:\n"
-				 "    %s", output_path);
-	}
-	else
-		check_ok();
-}
-
 /*
  * Callback function for processing results of query for
  * check_for_user_defined_encoding_conversions()'s UpgradeTask.  If the query
diff --git a/src/bin/pg_upgrade/controldata.c b/src/bin/pg_upgrade/controldata.c
index cffcd4b0eba..8188355240f 100644
--- a/src/bin/pg_upgrade/controldata.c
+++ b/src/bin/pg_upgrade/controldata.c
@@ -602,14 +602,12 @@ get_control_data(ClusterInfo *cluster)
 	/* verify that we got all the mandatory pg_control data */
 	if (!got_xid || !got_oid ||
 		!got_multi || !got_oldestxid ||
-		(!got_oldestmulti &&
-		 cluster->controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER) ||
+		!got_oldestmulti ||
 		!got_mxoff || (!live_check && !got_nextxlogfile) ||
 		!got_float8_pass_by_value || !got_align || !got_blocksz ||
 		!got_largesz || !got_walsz || !got_walseg || !got_ident ||
 		!got_index || !got_toast ||
-		(!got_large_object &&
-		 cluster->controldata.ctrl_ver >= LARGE_OBJECT_SIZE_PG_CONTROL_VER) ||
+		!got_large_object ||
 		!got_date_is_int || !got_data_checksum_version ||
 		(!got_default_char_signedness &&
 		 cluster->controldata.cat_ver >= DEFAULT_CHAR_SIGNEDNESS_CAT_VER))
@@ -630,8 +628,7 @@ get_control_data(ClusterInfo *cluster)
 		if (!got_multi)
 			pg_log(PG_REPORT, "  latest checkpoint next MultiXactId");
 
-		if (!got_oldestmulti &&
-			cluster->controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER)
+		if (!got_oldestmulti)
 			pg_log(PG_REPORT, "  latest checkpoint oldest MultiXactId");
 
 		if (!got_oldestxid)
@@ -670,8 +667,7 @@ get_control_data(ClusterInfo *cluster)
 		if (!got_toast)
 			pg_log(PG_REPORT, "  maximum TOAST chunk size");
 
-		if (!got_large_object &&
-			cluster->controldata.ctrl_ver >= LARGE_OBJECT_SIZE_PG_CONTROL_VER)
+		if (!got_large_object)
 			pg_log(PG_REPORT, "  large-object chunk size");
 
 		if (!got_date_is_int)
diff --git a/src/bin/pg_upgrade/exec.c b/src/bin/pg_upgrade/exec.c
index e1de61f36ee..479557abdcc 100644
--- a/src/bin/pg_upgrade/exec.c
+++ b/src/bin/pg_upgrade/exec.c
@@ -55,16 +55,7 @@ get_bin_version(ClusterInfo *cluster)
 	if (sscanf(cmd_output, "%*s %*s %d.%d", &v1, &v2) < 1)
 		pg_fatal("could not get pg_ctl version output from %s", cmd);
 
-	if (v1 < 10)
-	{
-		/* old style, e.g. 9.6.1 */
-		cluster->bin_version = v1 * 10000 + v2 * 100;
-	}
-	else
-	{
-		/* new style, e.g. 10.1 */
 		cluster->bin_version = v1 * 10000;
-	}
 }

@@ -353,17 +344,7 @@ check_data_dir(ClusterInfo *cluster)
 	check_single_dir(pg_data, "pg_subtrans");
 	check_single_dir(pg_data, PG_TBLSPC_DIR);
 	check_single_dir(pg_data, "pg_twophase");
-
-	/* pg_xlog has been renamed to pg_wal in v10 */
-	if (GET_MAJOR_VERSION(cluster->major_version) <= 906)
-		check_single_dir(pg_data, "pg_xlog");
-	else
 		check_single_dir(pg_data, "pg_wal");
-
-	/* pg_clog has been renamed to pg_xact in v10 */
-	if (GET_MAJOR_VERSION(cluster->major_version) <= 906)
-		check_single_dir(pg_data, "pg_clog");
-	else
 		check_single_dir(pg_data, "pg_xact");
 }
 
@@ -404,10 +385,6 @@ check_bin_dir(ClusterInfo *cluster, bool check_versions)
 	 */
 	get_bin_version(cluster);
 
-	/* pg_resetxlog has been renamed to pg_resetwal in version 10 */
-	if (GET_MAJOR_VERSION(cluster->bin_version) <= 906)
-		check_exec(cluster->bindir, "pg_resetxlog", check_versions);
-	else
 		check_exec(cluster->bindir, "pg_resetwal", check_versions);
 
 	if (cluster == &new_cluster)
diff --git a/src/bin/pg_upgrade/file.c b/src/bin/pg_upgrade/file.c
index 5b276008614..af82c0de490 100644
--- a/src/bin/pg_upgrade/file.c
+++ b/src/bin/pg_upgrade/file.c
@@ -20,12 +20,8 @@
 #include <linux/fs.h>
 #endif
 
-#include "access/visibilitymapdefs.h"
 #include "common/file_perm.h"
 #include "pg_upgrade.h"
-#include "storage/bufpage.h"
-#include "storage/checksum.h"
-#include "storage/checksum_impl.h"

 /*
@@ -196,166 +192,6 @@ linkFile(const char *src, const char *dst,
 }

-/*
- * rewriteVisibilityMap()
- *
- * Transform a visibility map file, copying from src to dst.
- * schemaName/relName are relation's SQL name (used for error messages only).
- *
- * In versions of PostgreSQL prior to catversion 201603011, PostgreSQL's
- * visibility map included one bit per heap page; it now includes two.
- * When upgrading a cluster from before that time to a current PostgreSQL
- * version, we could refuse to copy visibility maps from the old cluster
- * to the new cluster; the next VACUUM would recreate them, but at the
- * price of scanning the entire table.  So, instead, we rewrite the old
- * visibility maps in the new format.  That way, the all-visible bits
- * remain set for the pages for which they were set previously.  The
- * all-frozen bits are never set by this conversion; we leave that to VACUUM.
- */
-void
-rewriteVisibilityMap(const char *fromfile, const char *tofile,
-					 const char *schemaName, const char *relName)
-{
-	int			src_fd;
-	int			dst_fd;
-	PGIOAlignedBlock buffer;
-	PGIOAlignedBlock new_vmbuf;
-	ssize_t		totalBytesRead = 0;
-	ssize_t		src_filesize;
-	int			rewriteVmBytesPerPage;
-	BlockNumber new_blkno = 0;
-	struct stat statbuf;
-
-	/* Compute number of old-format bytes per new page */
-	rewriteVmBytesPerPage = (BLCKSZ - SizeOfPageHeaderData) / 2;
-
-	if ((src_fd = open(fromfile, O_RDONLY | PG_BINARY, 0)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not open file \"%s\": %m",
-				 schemaName, relName, fromfile);
-
-	if (fstat(src_fd, &statbuf) != 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not stat file \"%s\": %m",
-				 schemaName, relName, fromfile);
-
-	if ((dst_fd = open(tofile, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
-					   pg_file_create_mode)) < 0)
-		pg_fatal("error while copying relation \"%s.%s\": could not create file \"%s\": %m",
-				 schemaName, relName, tofile);
-
-	/* Save old file size */
-	src_filesize = statbuf.st_size;
-
-	/*
-	 * Turn each visibility map page into 2 pages one by one. Each new page
-	 * has the same page header as the old one.  If the last section of the
-	 * last page is empty, we skip it, mostly to avoid turning one-page
-	 * visibility maps for small relations into two pages needlessly.
-	 */
-	while (totalBytesRead < src_filesize)
-	{
-		ssize_t		bytesRead;
-		char	   *old_cur;
-		char	   *old_break;
-		char	   *old_blkend;
-		PageHeaderData pageheader;
-		bool		old_lastblk;
-
-		if ((bytesRead = read(src_fd, buffer.data, BLCKSZ)) != BLCKSZ)
-		{
-			if (bytesRead < 0)
-				pg_fatal("error while copying relation \"%s.%s\": could not read file \"%s\": %m",
-						 schemaName, relName, fromfile);
-			else
-				pg_fatal("error while copying relation \"%s.%s\": partial page found in file \"%s\"",
-						 schemaName, relName, fromfile);
-		}
-
-		totalBytesRead += BLCKSZ;
-		old_lastblk = (totalBytesRead == src_filesize);
-
-		/* Save the page header data */
-		memcpy(&pageheader, buffer.data, SizeOfPageHeaderData);
-
-		/*
-		 * These old_* variables point to old visibility map page. old_cur
-		 * points to current position on old page. old_blkend points to end of
-		 * old block.  old_break is the end+1 position on the old page for the
-		 * data that will be transferred to the current new page.
-		 */
-		old_cur = buffer.data + SizeOfPageHeaderData;
-		old_blkend = buffer.data + bytesRead;
-		old_break = old_cur + rewriteVmBytesPerPage;
-
-		while (old_break <= old_blkend)
-		{
-			char	   *new_cur;
-			bool		empty = true;
-			bool		old_lastpart;
-
-			/* First, copy old page header to new page */
-			memcpy(new_vmbuf.data, &pageheader, SizeOfPageHeaderData);
-
-			/* Rewriting the last part of the last old page? */
-			old_lastpart = old_lastblk && (old_break == old_blkend);
-
-			new_cur = new_vmbuf.data + SizeOfPageHeaderData;
-
-			/* Process old page bytes one by one, and turn it into new page. */
-			while (old_cur < old_break)
-			{
-				uint8		byte = *(uint8 *) old_cur;
-				uint16		new_vmbits = 0;
-				int			i;
-
-				/* Generate new format bits while keeping old information */
-				for (i = 0; i < BITS_PER_BYTE; i++)
-				{
-					if (byte & (1 << i))
-					{
-						empty = false;
-						new_vmbits |=
-							VISIBILITYMAP_ALL_VISIBLE << (BITS_PER_HEAPBLOCK * i);
-					}
-				}
-
-				/* Copy new visibility map bytes to new-format page */
-				new_cur[0] = (char) (new_vmbits & 0xFF);
-				new_cur[1] = (char) (new_vmbits >> 8);
-
-				old_cur++;
-				new_cur += BITS_PER_HEAPBLOCK;
-			}
-
-			/* If the last part of the last page is empty, skip writing it */
-			if (old_lastpart && empty)
-				break;
-
-			/* Set new checksum for visibility map page, if enabled */
-			if (new_cluster.controldata.data_checksum_version != PG_DATA_CHECKSUM_OFF)
-				((PageHeader) new_vmbuf.data)->pd_checksum =
-					pg_checksum_page(new_vmbuf.data, new_blkno);
-
-			errno = 0;
-			if (write(dst_fd, new_vmbuf.data, BLCKSZ) != BLCKSZ)
-			{
-				/* if write didn't set errno, assume problem is no disk space */
-				if (errno == 0)
-					errno = ENOSPC;
-				pg_fatal("error while copying relation \"%s.%s\": could not write file \"%s\": %m",
-						 schemaName, relName, tofile);
-			}
-
-			/* Advance for next new page */
-			old_break += rewriteVmBytesPerPage;
-			new_blkno++;
-		}
-	}
-
-	/* Clean up */
-	close(dst_fd);
-	close(src_fd);
-}
-
 void
 check_file_clone(void)
 {
diff --git a/src/bin/pg_upgrade/multixact_rewrite.c b/src/bin/pg_upgrade/multixact_rewrite.c
index 823984ec8f3..c45b3183684 100644
--- a/src/bin/pg_upgrade/multixact_rewrite.c
+++ b/src/bin/pg_upgrade/multixact_rewrite.c
@@ -25,10 +25,7 @@ static void RecordMultiXactMembers(SlruSegState *members_writer,
  * 32-bit offsets to the current format.
  *
  * Multixids in the range [from_multi, to_multi) are read from the old
- * cluster, and written in the new format.  An important edge case is that if
- * from_multi == to_multi, this initializes the new pg_multixact files in the
- * new format without trying to open any old files.  (We rely on that when
- * upgrading from PostgreSQL version 9.2 or below.)
+ * cluster, and written in the new format.
  *
  * Returns the new nextOffset value; the caller should set it in the new
  * control file.  The new members always start from offset 1, regardless of
@@ -42,6 +39,7 @@ rewrite_multixacts(MultiXactId from_multi, MultiXactId to_multi)
 	SlruSegState *members_writer;
 	char		dir[MAXPGPATH] = {0};
 	bool		prev_multixid_valid = false;
+	OldMultiXactReader *old_reader;
 
 	/*
 	 * The range of valid multi XIDs is unchanged by the conversion (they are
@@ -63,10 +61,6 @@ rewrite_multixacts(MultiXactId from_multi, MultiXactId to_multi)
 	 * Convert old multixids, if needed, by reading them one-by-one from the
 	 * old cluster.
 	 */
-	if (to_multi != from_multi)
-	{
-		OldMultiXactReader *old_reader;
-
 		old_reader = AllocOldMultiXactRead(old_cluster.pgdata,
 										   old_cluster.controldata.chkpnt_nxtmulti,
 										   old_cluster.controldata.chkpnt_nxtmxoff);
@@ -113,7 +107,6 @@ rewrite_multixacts(MultiXactId from_multi, MultiXactId to_multi)
 		}
 
 		FreeOldMultiXactReader(old_reader);
-	}
 
 	/* Write the final 'next' offset to the last SLRU page */
 	RecordMultiXactOffset(offsets_writer, to_multi,
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 2127d297bfe..e5d7920c1b1 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -714,13 +714,6 @@ create_new_objects(void)
 	end_progress_output();
 	check_ok();
 
-	/*
-	 * We don't have minmxids for databases or relations in pre-9.3 clusters,
-	 * so set those after we have restored the schema.
-	 */
-	if (GET_MAJOR_VERSION(old_cluster.major_version) <= 902)
-		set_frozenxids(true);
-
 	/* update new_cluster info now that we have objects in the databases */
 	get_db_rel_and_slot_infos(&new_cluster);
 }
@@ -777,10 +770,7 @@ copy_xact_xlog_xid(void)
 	 * Copy old commit logs to new data dir. pg_clog has been renamed to
 	 * pg_xact in post-10 clusters.
 	 */
-	copy_subdir_files(GET_MAJOR_VERSION(old_cluster.major_version) <= 906 ?
-					  "pg_clog" : "pg_xact",
-					  GET_MAJOR_VERSION(new_cluster.major_version) <= 906 ?
-					  "pg_clog" : "pg_xact");
+	copy_subdir_files("pg_xact", "pg_xact");
 
 	prep_status("Setting oldest XID for new cluster");
 	exec_prog(UTILITY_LOG_FILE, NULL, true, true,
@@ -809,7 +799,6 @@ copy_xact_xlog_xid(void)
 	check_ok();
 
 	/* Copy or convert pg_multixact files */
-	Assert(new_cluster.controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER);
 	Assert(new_cluster.controldata.cat_ver >= MULTIXACTOFFSET_FORMATCHANGE_CAT_VER);
 	if (old_cluster.controldata.cat_ver >= MULTIXACTOFFSET_FORMATCHANGE_CAT_VER)
 	{
@@ -844,25 +833,7 @@ copy_xact_xlog_xid(void)
 		 * Determine the range of multixacts to convert.
 		 */
 		nxtmulti = old_cluster.controldata.chkpnt_nxtmulti;
-		if (old_cluster.controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER)
-		{
-			/* Versions 9.3 - 18: convert all multixids  */
 			oldstMulti = old_cluster.controldata.chkpnt_oldstMulti;
-		}
-		else
-		{
-			/*
-			 * In PostgreSQL 9.2 and below, multitransactions were only used
-			 * for row locking, and as such don't need to be preserved during
-			 * upgrade.  In that case, we utilize rewrite_multixacts() just to
-			 * initialize new, empty files in the new format.
-			 *
-			 * It's important that the oldest multi is set to the latest value
-			 * used by the old system, so that multixact.c returns the empty
-			 * set for multis that might be present on disk.
-			 */
-			oldstMulti = nxtmulti;
-		}
 		/* handle wraparound */
 		if (nxtmulti < FirstMultiXactId)
 			nxtmulti = FirstMultiXactId;
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 1d767bbda2d..5a0d2045be5 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -101,19 +101,6 @@ extern char *output_files[];
 #endif

-/*
- * The format of visibility map was changed with this 9.6 commit.
- */
-#define VISIBILITY_MAP_FROZEN_BIT_CAT_VER 201603011
-
-/*
- * pg_multixact format changed in 9.3 commit 0ac5ad5134f2769ccbaefec73844f85,
- * ("Improve concurrency of foreign key locking") which also updated catalog
- * version to this value.  pg_upgrade behavior depends on whether old and new
- * server versions are both newer than this, or only the new one is.
- */
-#define MULTIXACT_FORMATCHANGE_CAT_VER 201301231
-
 /*
  * MultiXactOffset was changed from 32-bit to 64-bit in version 19, at this
  * catalog version.  pg_multixact files need to be converted when upgrading
@@ -121,17 +108,6 @@ extern char *output_files[];
  */
 #define MULTIXACTOFFSET_FORMATCHANGE_CAT_VER 202512091
 
-/*
- * large object chunk size added to pg_controldata,
- * commit 5f93c37805e7485488480916b4585e098d3cc883
- */
-#define LARGE_OBJECT_SIZE_PG_CONTROL_VER 942
-
-/*
- * change in JSONB format during 9.4 beta
- */
-#define JSONB_FORMAT_CHANGE_CAT_VER 201409291
-
 /*
  * The control file was changed to have the default char signedness,
  * commit 44fe30fdab6746a287163e7cc093fd36cda8eb92
@@ -429,8 +405,6 @@ void		copyFileByRange(const char *src, const char *dst,
 							const char *schemaName, const char *relName);
 void		linkFile(const char *src, const char *dst,
 					 const char *schemaName, const char *relName);
-void		rewriteVisibilityMap(const char *fromfile, const char *tofile,
-								 const char *schemaName, const char *relName);
 void		check_file_clone(void);
 void		check_copy_file_range(void);
 void		check_hard_link(transferMode transfer_mode);
@@ -500,10 +474,7 @@ unsigned int str2uint(const char *str);
 
 /* version.c */
 
-bool		jsonb_9_4_check_applicable(ClusterInfo *cluster);
 bool		protocol_negotiation_supported(const ClusterInfo *cluster);
-void		old_9_6_invalidate_hash_indexes(ClusterInfo *cluster,
-											bool check_mode);
 
 void		report_extension_updates(ClusterInfo *cluster);
 
diff --git a/src/bin/pg_upgrade/relfilenumber.c b/src/bin/pg_upgrade/relfilenumber.c
index d5088447e0d..ec2ff7acb21 100644
--- a/src/bin/pg_upgrade/relfilenumber.c
+++ b/src/bin/pg_upgrade/relfilenumber.c
@@ -18,7 +18,7 @@
 #include "pg_upgrade.h"
 
 static void transfer_single_new_db(FileNameMap *maps, int size, char *old_tablespace, char *new_tablespace);
-static void transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_frozenbit);
+static void transfer_relfile(FileNameMap *map, const char *type_suffix);
 
 /*
  * The following set of sync_queue_* functions are used for --swap to reduce
@@ -496,25 +496,10 @@ transfer_single_new_db(FileNameMap *maps, int size,
 					   char *old_tablespace, char *new_tablespace)
 {
 	int			mapnum;
-	bool		vm_must_add_frozenbit = false;
-
-	/*
-	 * Do we need to rewrite visibilitymap?
-	 */
-	if (old_cluster.controldata.cat_ver < VISIBILITY_MAP_FROZEN_BIT_CAT_VER &&
-		new_cluster.controldata.cat_ver >= VISIBILITY_MAP_FROZEN_BIT_CAT_VER)
-		vm_must_add_frozenbit = true;
 
 	/* --swap has its own subroutine */
 	if (user_opts.transfer_mode == TRANSFER_MODE_SWAP)
 	{
-		/*
-		 * We don't support --swap to upgrade from versions that require
-		 * rewriting the visibility map.  We should've failed already if
-		 * someone tries to do that.
-		 */
-		Assert(!vm_must_add_frozenbit);
-
 		do_swap(maps, size, old_tablespace, new_tablespace);
 		return;
 	}
@@ -525,13 +510,13 @@ transfer_single_new_db(FileNameMap *maps, int size,
 			strcmp(maps[mapnum].old_tablespace, old_tablespace) == 0)
 		{
 			/* transfer primary file */
-			transfer_relfile(&maps[mapnum], "", vm_must_add_frozenbit);
+			transfer_relfile(&maps[mapnum], "");
 
 			/*
 			 * Copy/link any fsm and vm files, if they exist
 			 */
-			transfer_relfile(&maps[mapnum], "_fsm", vm_must_add_frozenbit);
-			transfer_relfile(&maps[mapnum], "_vm", vm_must_add_frozenbit);
+			transfer_relfile(&maps[mapnum], "_fsm");
+			transfer_relfile(&maps[mapnum], "_vm");
 		}
 	}
 }
@@ -540,12 +525,10 @@ transfer_single_new_db(FileNameMap *maps, int size,
 /*
  * transfer_relfile()
  *
- * Copy or link file from old cluster to new one.  If vm_must_add_frozenbit
- * is true, visibility map forks are converted and rewritten, even in link
- * mode.
+ * Copy or link file from old cluster to new one.
  */
 static void
-transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_frozenbit)
+transfer_relfile(FileNameMap *map, const char *type_suffix)
 {
 	char		old_file[MAXPGPATH];
 	char		new_file[MAXPGPATH];
@@ -604,14 +587,6 @@ transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_fro
 		/* Copying files might take some time, so give feedback. */
 		pg_log(PG_STATUS, "%s", old_file);
 
-		if (vm_must_add_frozenbit && strcmp(type_suffix, "_vm") == 0)
-		{
-			/* Need to rewrite visibility map format */
-			pg_log(PG_VERBOSE, "rewriting \"%s\" to \"%s\"",
-				   old_file, new_file);
-			rewriteVisibilityMap(old_file, new_file, map->nspname, map->relname);
-		}
-		else
 			switch (user_opts.transfer_mode)
 			{
 				case TRANSFER_MODE_CLONE:
diff --git a/src/bin/pg_upgrade/version.c b/src/bin/pg_upgrade/version.c
index 047670d4acb..9e83d4659be 100644
--- a/src/bin/pg_upgrade/version.c
+++ b/src/bin/pg_upgrade/version.c
@@ -12,22 +12,6 @@
 #include "fe_utils/string_utils.h"
 #include "pg_upgrade.h"
 
-/*
- * version_hook functions for check_for_data_types_usage in order to determine
- * whether a data type check should be executed for the cluster in question or
- * not.
- */
-bool
-jsonb_9_4_check_applicable(ClusterInfo *cluster)
-{
-	/* JSONB changed its storage format during 9.4 beta */
-	if (GET_MAJOR_VERSION(cluster->major_version) == 904 &&
-		cluster->controldata.cat_ver < JSONB_FORMAT_CHANGE_CAT_VER)
-		return true;
-
-	return false;
-}
-
 /*
  * Older servers can't support newer protocol versions, so their connection
  * strings will need to lock max_protocol_version to 3.0.
@@ -46,117 +30,6 @@ protocol_negotiation_supported(const ClusterInfo *cluster)
 	return (GET_MAJOR_VERSION(cluster->major_version) >= 1100);
 }
 
-/*
- * old_9_6_invalidate_hash_indexes()
- *	9.6 -> 10
- *	Hash index binary format has changed from 9.6->10.0
- */
-void
-old_9_6_invalidate_hash_indexes(ClusterInfo *cluster, bool check_mode)
-{
-	int			dbnum;
-	FILE	   *script = NULL;
-	bool		found = false;
-	char	   *output_path = "reindex_hash.sql";
-
-	prep_status("Checking for hash indexes");
-
-	for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
-	{
-		PGresult   *res;
-		bool		db_used = false;
-		int			ntups;
-		int			rowno;
-		int			i_nspname,
-					i_relname;
-		DbInfo	   *active_db = &cluster->dbarr.dbs[dbnum];
-		PGconn	   *conn = connectToServer(cluster, active_db->db_name);
-
-		/* find hash indexes */
-		res = executeQueryOrDie(conn,
-								"SELECT n.nspname, c.relname "
-								"FROM	pg_catalog.pg_class c, "
-								"		pg_catalog.pg_index i, "
-								"		pg_catalog.pg_am a, "
-								"		pg_catalog.pg_namespace n "
-								"WHERE	i.indexrelid = c.oid AND "
-								"		c.relam = a.oid AND "
-								"		c.relnamespace = n.oid AND "
-								"		a.amname = 'hash'"
-			);
-
-		ntups = PQntuples(res);
-		i_nspname = PQfnumber(res, "nspname");
-		i_relname = PQfnumber(res, "relname");
-		for (rowno = 0; rowno < ntups; rowno++)
-		{
-			found = true;
-			if (!check_mode)
-			{
-				if (script == NULL && (script = fopen_priv(output_path, "w")) == NULL)
-					pg_fatal("could not open file \"%s\": %m", output_path);
-				if (!db_used)
-				{
-					PQExpBufferData connectbuf;
-
-					initPQExpBuffer(&connectbuf);
-					appendPsqlMetaConnect(&connectbuf, active_db->db_name);
-					fputs(connectbuf.data, script);
-					termPQExpBuffer(&connectbuf);
-					db_used = true;
-				}
-				fprintf(script, "REINDEX INDEX %s.%s;\n",
-						quote_identifier(PQgetvalue(res, rowno, i_nspname)),
-						quote_identifier(PQgetvalue(res, rowno, i_relname)));
-			}
-		}
-
-		PQclear(res);
-
-		if (!check_mode && db_used)
-		{
-			/* mark hash indexes as invalid */
-			PQclear(executeQueryOrDie(conn,
-									  "UPDATE pg_catalog.pg_index i "
-									  "SET	indisvalid = false "
-									  "FROM	pg_catalog.pg_class c, "
-									  "		pg_catalog.pg_am a, "
-									  "		pg_catalog.pg_namespace n "
-									  "WHERE	i.indexrelid = c.oid AND "
-									  "		c.relam = a.oid AND "
-									  "		c.relnamespace = n.oid AND "
-									  "		a.amname = 'hash'"));
-		}
-
-		PQfinish(conn);
-	}
-
-	if (script)
-		fclose(script);
-
-	if (found)
-	{
-		report_status(PG_WARNING, "warning");
-		if (check_mode)
-			pg_log(PG_WARNING, "\n"
-				   "Your installation contains hash indexes.  These indexes have different\n"
-				   "internal formats between your old and new clusters, so they must be\n"
-				   "reindexed with the REINDEX command.  After upgrading, you will be given\n"
-				   "REINDEX instructions.");
-		else
-			pg_log(PG_WARNING, "\n"
-				   "Your installation contains hash indexes.  These indexes have different\n"
-				   "internal formats between your old and new clusters, so they must be\n"
-				   "reindexed with the REINDEX command.  The file\n"
-				   "    %s\n"
-				   "when executed by psql by the database superuser will recreate all invalid\n"
-				   "indexes; until then, none of these indexes will be used.",
-				   output_path);
-	}
-	else
-		check_ok();
-}
-
 /*
  * Callback function for processing results of query for
  * report_extension_updates()'s UpgradeTask.  If the query returned any rows,
-- 
2.50.1 (Apple Git-155)

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