Tom Lane wrote:
> Magnus Hagander <mag...@hagander.net> writes:
>>>> As for -c, the solution would be to issue DROP IF EXISTS
>>>> statements. Is there any particular reason why we don't?
>>> I think we did that to avoid damaging portability and backwards
>>> compatibility of the dump files. The backwards compatibility argument
>>> is pretty weak by now, but the "it's not standard SQL" argument still
>>> has force.
>
>> IIRC the drop statements are generated by pg_restore and not stored in
>> the archive. So we could do the if exists by default and have a switch
>> to turn it off for a compatible dump, perhaps?
>
> No, the text of the statements is in the archive; though it might not be
> too painful to have pg_restore edit them to insert "IF EXISTS". You
> don't need an extra switch, just do this if -1 is in use (and document
> that that switch reduces the standard-ness of the output...)
Something along the line of this?
(This is for the actual injection, I still haven't implemented
switch/decided when to actually include it, so this is not for
application yet - just for a comment on the general method..)
//Magnus
*** a/src/bin/pg_dump/pg_backup_archiver.c
--- b/src/bin/pg_dump/pg_backup_archiver.c
***************
*** 123,128 **** CloseArchive(Archive *AHX)
--- 123,144 ----
strerror(errno));
}
+ /*
+ * List all objects that can be DROPped that are made up of more
+ * than a single word.
+ */
+ static const char *multiword_drops[] = {
+ "FOREIGN DATA WRAPPER",
+ "OPERATOR CLASS",
+ "OPERATOR FAMILY",
+ "TEXT SEARCH CONFIGURATION",
+ "TEXT SEARCH DICTIONARY",
+ "TEXT SEARCH PARSER",
+ "TEXT SEARCH TEMPLATE",
+ "USER MAPPING",
+ NULL
+ };
+
/* Public */
void
RestoreArchive(Archive *AHX, RestoreOptions *ropt)
***************
*** 249,256 **** RestoreArchive(Archive *AHX, RestoreOptions *ropt)
/* Select owner and schema as necessary */
_becomeOwner(AH, te);
_selectOutputSchema(AH, te->namespace);
! /* Drop it */
! ahprintf(AH, "%s", te->dropStmt);
}
}
--- 265,308 ----
/* Select owner and schema as necessary */
_becomeOwner(AH, te);
_selectOutputSchema(AH, te->namespace);
! /*
! * Figure out if it's something we can do DROP IF EXISTS on.
! * Check for "DROP " just to be sure.
! */
! if (strncmp(te->dropStmt, "DROP ", 5) == 0)
! {
! char *cp = te->dropStmt + 5;
! char *insertpoint = NULL;
! char *newstr = NULL;
! int i;
!
! /*
! * Assume that all objects can be DROP IF EXISTS:ed. However,
! * some have more than one word in them, so we need to figure
! * out exactly where to insert the IF EXISTS.
! */
! for (i = 0; multiword_drops[i] != NULL; i++)
! {
! if (strncmp(cp, multiword_drops[i], strlen(multiword_drops[i])) == 0)
! {
! insertpoint = cp + strlen(multiword_drops[i]);
! break;
! }
! }
! if (insertpoint == NULL)
! insertpoint = strchr(cp, ' ');
! if (insertpoint == NULL)
! die_horribly(AH,modulename,"malformatted DROP statement: %s", te->dropStmt);
!
! newstr = calloc(strlen(te->dropStmt) + 11, 1); /* "IF EXISTS " + terminator */
! strncpy(newstr, te->dropStmt, insertpoint - te->dropStmt);
! strcat(newstr, " IF EXISTS");
! strcat(newstr, insertpoint);
! ahprintf(AH, "%s", newstr);
! free(newstr);
! }
! else
! ahprintf(AH, "%s", te->dropStmt);
}
}
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