0001-Fixup-dump-toast-compression-method.patch

From 40b53e24932b1f9203092a7f6972804af5a7a45b Mon Sep 17 00:00:00 2001
From: Dilip Kumar <dilipkumar@localhost.localdomain>
Date: Sat, 20 Mar 2021 13:14:39 +0530
Subject: [PATCH] Fixup, dump toast compression method

---
 src/bin/pg_dump/pg_backup.h          |  1 +
 src/bin/pg_dump/pg_backup_archiver.c |  4 +++
 src/bin/pg_dump/pg_dump.c            | 66 ++++++++++++++++++++++--------------
 src/bin/pg_dump/t/002_pg_dump.pl     | 12 +++----
 4 files changed, 52 insertions(+), 31 deletions(-)

diff --git a/src/bin/pg_dump/pg_backup.h b/src/bin/pg_dump/pg_backup.h
index 0296b9b..02019fc 100644
--- a/src/bin/pg_dump/pg_backup.h
+++ b/src/bin/pg_dump/pg_backup.h
@@ -210,6 +210,7 @@ typedef struct Archive
 	/* other important stuff */
 	char	   *searchpath;		/* search_path to set during restore */
 	char	   *use_role;		/* Issue SET ROLE to this */
+	char	   *default_toast_compression;
 
 	/* error handling */
 	bool		exit_on_error;	/* whether to exit on SQL errors... */
diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 1f82c64..a25f4d1 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -3152,6 +3152,10 @@ _doSetFixedOutputState(ArchiveHandle *AH)
 	else
 		ahprintf(AH, "SET row_security = off;\n");
 
+	/* Select the dump-time default toast compression */
+	if (AH->public.default_toast_compression)
+		ahprintf(AH, "SET default_toast_compression = '%s';\n",
+				 AH->public.default_toast_compression);
 	ahprintf(AH, "\n");
 }
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index f8bec3f..7bbcaac 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1248,6 +1248,21 @@ setup_connection(Archive *AH, const char *dumpencoding,
 
 		AH->sync_snapshot_id = get_synchronized_snapshot(AH);
 	}
+
+	/*
+	 * Get default TOAST compression method, but not if the server's too
+	 * old to support the feature or if the user doesn't want to dump that
+	 * information anyway.
+	 */
+	if (AH->remoteVersion >= 140000 && !dopt->no_toast_compression)
+	{
+		PGresult   *res;
+
+		res = ExecuteSqlQueryForSingleRow(AH,
+										  "SHOW default_toast_compression");
+		AH->default_toast_compression = pg_strdup(PQgetvalue(res, 0, 0));
+		PQclear(res);
+	}
 }
 
 /* Set up connection for a parallel worker process */
@@ -15905,31 +15920,6 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 										  tbinfo->atttypnames[j]);
 					}
 
-					/*
-					 * Attribute compression
-					 */
-					if (!dopt->no_toast_compression &&
-						tbinfo->attcompression != NULL)
-					{
-						char	   *cmname;
-
-						switch (tbinfo->attcompression[j])
-						{
-							case 'p':
-								cmname = "pglz";
-								break;
-							case 'l':
-								cmname = "lz4";
-								break;
-							default:
-								cmname = NULL;
-								break;
-						}
-
-						if (cmname != NULL)
-							appendPQExpBuffer(q, " COMPRESSION %s", cmname);
-					}
-
 					if (print_default)
 					{
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
@@ -16348,6 +16338,32 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 								  qualrelname,
 								  fmtId(tbinfo->attnames[j]),
 								  tbinfo->attfdwoptions[j]);
+
+			/*
+			 * Dump per-column compression options
+			 */
+			if (!dopt->no_toast_compression && tbinfo->attcompression != NULL)
+			{
+				char	   *cmname;
+
+				switch (tbinfo->attcompression[j])
+				{
+					case 'p':
+						cmname = "pglz";
+						break;
+					case 'l':
+						cmname = "lz4";
+						break;
+					default:
+						cmname = NULL;
+						break;
+				}
+
+				if (cmname != NULL &&
+					strcmp(cmname, fout->default_toast_compression) != 0)
+					appendPQExpBuffer(q, "ALTER TABLE %s ALTER COLUMN %s\nSET COMPRESSION %s;\n",
+										qualrelname, fmtId(tbinfo->attnames[j]), cmname);
+			}
 		}
 
 		if (ftoptions)
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index bc91bb1..737e464 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -2284,9 +2284,9 @@ my %tests = (
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 text COMPRESSION\E\D*,\n
-			\s+\Qcol3 text COMPRESSION\E\D*,\n
-			\s+\Qcol4 text COMPRESSION\E\D*,\n
+			\s+\Qcol2 text,\E\n
+			\s+\Qcol3 text,\E\n
+			\s+\Qcol4 text,\E\n
 			\s+\QCONSTRAINT test_table_col1_check CHECK ((col1 <= 1000))\E\n
 			\Q)\E\n
 			\QWITH (autovacuum_enabled='false', fillfactor='80');\E\n/xm,
@@ -2326,7 +2326,7 @@ my %tests = (
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_second_table (\E
 			\n\s+\Qcol1 integer,\E
-			\n\s+\Qcol2 text COMPRESSION\E\D*
+			\n\s+\Qcol2 text\E
 			\n\);
 			/xm,
 		like =>
@@ -2441,7 +2441,7 @@ my %tests = (
 			\n\s+\Qcol1 integer,\E
 			\n\s+\Qcol2 boolean,\E
 			\n\s+\Qcol3 boolean,\E
-			\n\s+\Qcol4 bit(5) COMPRESSION\E\D*,
+			\n\s+\Qcol4 bit(5),\E
 			\n\s+\Qcol5 double precision\E
 			\n\);
 			/xm,
@@ -2459,7 +2459,7 @@ my %tests = (
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_identity (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 text COMPRESSION\E\D*\n
+			\s+\Qcol2 text\E\n
 			\);
 			.*
 			\QALTER TABLE dump_test.test_table_identity ALTER COLUMN col1 ADD GENERATED ALWAYS AS IDENTITY (\E\n
-- 
1.8.3.1