Fix pg_dump's --if-exists for large objects

This was born broken in 9067310cc5dd590e36c2c3219dbf3961d7c9f8cb.

Per trouble report from Joachim Wieland.

Pavel Stěhule and Álvaro Herrera

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index fedd74c5e69d77be043d8e2468d8b7eba2664302..046611c39d2611861b5a51368a6f86c4935c1e06 100644 (file)
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -428,60 +428,75 @@ RestoreArchive(Archive *AHX)
                                        }
                                        else
                                        {
-                                               char            buffer[40];
-                                               char       *mark;
-                                               char       *dropStmt = pg_strdup(te->dropStmt);
-                                               char       *dropStmtPtr = dropStmt;
-                                               PQExpBuffer ftStmt = createPQExpBuffer();
-
                                                /*
-                                                * Need to inject IF EXISTS clause after ALTER TABLE
-                                                * part in ALTER TABLE .. DROP statement
+                                                * Inject an appropriate spelling of "if exists".  For
+                                                * large objects, we have a separate routine that
+                                                * knows how to do it, without depending on
+                                                * te->dropStmt; use that.  For other objects we need
+                                                * to parse the command.
+                                                *
                                                 */
-                                               if (strncmp(dropStmt, "ALTER TABLE", 11) == 0)
+                                               if (strncmp(te->desc, "BLOB", 4) == 0)
                                                {
-                                                       appendPQExpBuffer(ftStmt,
-                                                                                         "ALTER TABLE IF EXISTS");
-                                                       dropStmt = dropStmt + 11;
+                                                       DropBlobIfExists(AH, te->catalogId.oid);
                                                }
-
-                                               /*
-                                                * ALTER TABLE..ALTER COLUMN..DROP DEFAULT does not
-                                                * support the IF EXISTS clause, and therefore we
-                                                * simply emit the original command for such objects.
-                                                * For other objects, we need to extract the first
-                                                * part of the DROP which includes the object type.
-                                                * Most of the time this matches te->desc, so search
-                                                * for that; however for the different kinds of
-                                                * CONSTRAINTs, we know to search for hardcoded "DROP
-                                                * CONSTRAINT" instead.
-                                                */
-                                               if (strcmp(te->desc, "DEFAULT") == 0)
-                                                       appendPQExpBuffer(ftStmt, "%s", dropStmt);
                                                else
                                                {
-                                                       if (strcmp(te->desc, "CONSTRAINT") == 0 ||
-                                                               strcmp(te->desc, "CHECK CONSTRAINT") == 0 ||
-                                                               strcmp(te->desc, "FK CONSTRAINT") == 0)
-                                                               strcpy(buffer, "DROP CONSTRAINT");
+                                                       char            buffer[40];
+                                                       char       *mark;
+                                                       char       *dropStmt = pg_strdup(te->dropStmt);
+                                                       char       *dropStmtPtr = dropStmt;
+                                                       PQExpBuffer ftStmt = createPQExpBuffer();
+
+                                                       /*
+                                                        * Need to inject IF EXISTS clause after ALTER
+                                                        * TABLE part in ALTER TABLE .. DROP statement
+                                                        */
+                                                       if (strncmp(dropStmt, "ALTER TABLE", 11) == 0)
+                                                       {
+                                                               appendPQExpBuffer(ftStmt,
+                                                                                                 "ALTER TABLE IF EXISTS");
+                                                               dropStmt = dropStmt + 11;
+                                                       }
+
+                                                       /*
+                                                        * ALTER TABLE..ALTER COLUMN..DROP DEFAULT does
+                                                        * not support the IF EXISTS clause, and therefore
+                                                        * we simply emit the original command for such
+                                                        * objects. For other objects, we need to extract
+                                                        * the first part of the DROP which includes the
+                                                        * object type. Most of the time this matches
+                                                        * te->desc, so search for that; however for the
+                                                        * different kinds of CONSTRAINTs, we know to
+                                                        * search for hardcoded "DROP CONSTRAINT" instead.
+                                                        */
+                                                       if (strcmp(te->desc, "DEFAULT") == 0)
+                                                               appendPQExpBuffer(ftStmt, "%s", dropStmt);
                                                        else
-                                                               snprintf(buffer, sizeof(buffer), "DROP %s",
-                                                                                te->desc);
+                                                       {
+                                                               if (strcmp(te->desc, "CONSTRAINT") == 0 ||
+                                                                strcmp(te->desc, "CHECK CONSTRAINT") == 0 ||
+                                                                       strcmp(te->desc, "FK CONSTRAINT") == 0)
+                                                                       strcpy(buffer, "DROP CONSTRAINT");
+                                                               else
+                                                                       snprintf(buffer, sizeof(buffer), "DROP %s",
+                                                                                        te->desc);
 
-                                                       mark = strstr(dropStmt, buffer);
-                                                       Assert(mark != NULL);
+                                                               mark = strstr(dropStmt, buffer);
+                                                               Assert(mark != NULL);
 
-                                                       *mark = '\0';
-                                                       appendPQExpBuffer(ftStmt, "%s%s IF EXISTS%s",
-                                                                                         dropStmt, buffer,
-                                                                                         mark + strlen(buffer));
-                                               }
+                                                               *mark = '\0';
+                                                               appendPQExpBuffer(ftStmt, "%s%s IF EXISTS%s",
+                                                                                                 dropStmt, buffer,
+                                                                                                 mark + strlen(buffer));
+                                                       }
 
-                                               ahprintf(AH, "%s", ftStmt->data);
+                                                       ahprintf(AH, "%s", ftStmt->data);
 
-                                               destroyPQExpBuffer(ftStmt);
+                                                       destroyPQExpBuffer(ftStmt);
 
-                                               pg_free(dropStmtPtr);
+                                                       pg_free(dropStmtPtr);
+                                               }
                                        }
                                }
                        }