Teach vacuumlo to limit number of removals, via new -l option.

Also, handle failure better: don't just blindly keep trying to delete
stuff after the transaction has already failed.

Tim Lewis, reviewed by Josh Kupershmidt, with further hacking by me.

diff --git a/contrib/vacuumlo/vacuumlo.c b/contrib/vacuumlo/vacuumlo.c
index f6e2a28cf38cc5645c83a6eb0b73aebe87bdb2cc..6818d4ac43628d7b225f4a0651364566dc9ba9e2 100644 (file)
--- a/contrib/vacuumlo/vacuumlo.c
+++ b/contrib/vacuumlo/vacuumlo.c
@@ -48,6 +48,7 @@ struct _param
    char       *pg_host;
    int         verbose;
    int         dry_run;
+   long        transaction_limit;
 };
 
 int            vacuumlo(char *, struct _param *);
@@ -65,11 +66,12 @@ vacuumlo(char *database, struct _param * param)
    PGresult   *res,
               *res2;
    char        buf[BUFSIZE];
-   int         matched;
-   int         deleted;
+   long        matched;
+   long        deleted;
    int         i;
    static char *password = NULL;
    bool        new_pass;
+   bool        success = true;
 
    if (param->pg_prompt == TRI_YES && password == NULL)
        password = simple_prompt("Password: ", 100, false);
@@ -280,12 +282,19 @@ vacuumlo(char *database, struct _param * param)
            {
                fprintf(stderr, "\nFailed to remove lo %u: ", lo);
                fprintf(stderr, "%s", PQerrorMessage(conn));
+               if (PQtransactionStatus(conn) == PQTRANS_INERROR)
+               {
+                   success = false;
+                   break;
+               }
            }
            else
                deleted++;
        }
        else
            deleted++;
+       if (param->transaction_limit != 0 && deleted >= param->transaction_limit)
+           break;
    }
    PQclear(res);
 
@@ -298,10 +307,20 @@ vacuumlo(char *database, struct _param * param)
    PQfinish(conn);
 
    if (param->verbose)
-       fprintf(stdout, "\r%s %d large objects from %s.\n",
-          (param->dry_run ? "Would remove" : "Removed"), deleted, database);
+   {
+       if (param->dry_run)
+           fprintf(stdout, "\rWould remove %ld large objects from %s.\n",
+                   deleted, database);
+       else if (success)
+           fprintf(stdout,
+                   "\rSuccessfully removed %ld large objects from %s.\n",
+                   deleted, database);
+       else
+           fprintf(stdout, "\rRemoval from %s failed at object %ld of %ld.\n",
+                   database, deleted, matched);
+   }
 
-   return 0;
+   return ((param->dry_run || success) ? 0 : -1);
 }
 
 void
@@ -311,6 +330,7 @@ usage(const char *progname)
    printf("Usage:\n  %s [OPTION]... DBNAME...\n\n", progname);
    printf("Options:\n");
    printf("  -h HOSTNAME  database server host or socket directory\n");
+   printf("  -l LIMIT     stop after removing LIMIT large objects\n");
    printf("  -n           don't remove large objects, just show what would be done\n");
    printf("  -p PORT      database server port\n");
    printf("  -U USERNAME  user name to connect as\n");
@@ -342,6 +362,7 @@ main(int argc, char **argv)
    param.pg_port = NULL;
    param.verbose = 0;
    param.dry_run = 0;
+   param.transaction_limit = 0;
 
    if (argc > 1)
    {
@@ -359,7 +380,7 @@ main(int argc, char **argv)
 
    while (1)
    {
-       c = getopt(argc, argv, "h:U:p:vnwW");
+       c = getopt(argc, argv, "h:l:U:p:vnwW");
        if (c == -1)
            break;
 
@@ -395,6 +416,16 @@ main(int argc, char **argv)
                }
                param.pg_port = strdup(optarg);
                break;
+           case 'l':
+               param.transaction_limit = strtol(optarg, NULL, 10);
+               if (param.transaction_limit < 0)
+               {
+                   fprintf(stderr,
+               "%s: transaction limit must not be negative (0 disables)\n",
+                       progname);
+                   exit(1);
+               }
+               break;
            case 'h':
                param.pg_host = strdup(optarg);
                break;

diff --git a/doc/src/sgml/vacuumlo.sgml b/doc/src/sgml/vacuumlo.sgml
index 471a6ca32be9e75e7a38b3fe51891373ce02e357..0ae39c71d2c00c5c9f27e195bbf5ad1423a945cb 100644 (file)
--- a/doc/src/sgml/vacuumlo.sgml
+++ b/doc/src/sgml/vacuumlo.sgml
@@ -56,6 +56,16 @@ vacuumlo [options] database [database2 ... databaseN]
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><option>-l</option> <replaceable>limit</></term>
+    <listitem>
+     <para>
+      Stop after removing LIMIT large objects.  Useful to avoid 
+      exceeding <xref linkend="guc-max-locks-per-transaction">.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><option>-w</></term>
     <term><option>--no-password</></term>