From 9067310cc5dd590e36c2c3219dbf3961d7c9f8cb Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Mon, 3 Mar 2014 15:02:18 -0300 Subject: [PATCH] pg_dump et al: Add --if-exists option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This option makes pg_dump, pg_dumpall and pg_restore inject an IF EXISTS clause to each DROP command they emit. (In pg_dumpall, the clause is not added to individual objects drops, but rather to the CREATE DATABASE commands, as well as CREATE ROLE and CREATE TABLESPACE.) This allows for a better user dump experience when using --clean in case some objects do not already exist. Per bug #7873 by Dave Rolsky. Author: Pavel Stěhule Reviewed-by: Jeevan Chalke, Álvaro Herrera, Josh Kupershmidt --- doc/src/sgml/ref/pg_dump.sgml | 14 +++++- doc/src/sgml/ref/pg_dumpall.sgml | 11 +++++ doc/src/sgml/ref/pg_restore.sgml | 14 +++++- src/bin/pg_dump/pg_backup.h | 1 + src/bin/pg_dump/pg_backup_archiver.c | 73 +++++++++++++++++++++++++++- src/bin/pg_dump/pg_dump.c | 7 +++ src/bin/pg_dump/pg_dumpall.c | 22 +++++++-- src/bin/pg_dump/pg_restore.c | 11 +++++ 8 files changed, 146 insertions(+), 7 deletions(-) diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 40c69f0542..1f0d4ded32 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -145,7 +145,8 @@ PostgreSQL documentation Output commands to clean (drop) database objects prior to outputting the commands for creating them. - (Restore might generate some harmless error messages, if any objects + (Unless @@ -649,6 +650,17 @@ PostgreSQL documentation + + + + + Use conditional commands (i.e. add an IF EXISTS + clause) when cleaning database objects. This option is not valid + unless + + + diff --git a/doc/src/sgml/ref/pg_dumpall.sgml b/doc/src/sgml/ref/pg_dumpall.sgml index f33793985f..fcf5f77a6d 100644 --- a/doc/src/sgml/ref/pg_dumpall.sgml +++ b/doc/src/sgml/ref/pg_dumpall.sgml @@ -300,6 +300,17 @@ PostgreSQL documentation + + + + + Use conditional commands (i.e. add an IF EXISTS + clause) to clean databases and other objects. This option is not valid + unless + + + diff --git a/doc/src/sgml/ref/pg_restore.sgml b/doc/src/sgml/ref/pg_restore.sgml index cd60b2558a..4bc30ce679 100644 --- a/doc/src/sgml/ref/pg_restore.sgml +++ b/doc/src/sgml/ref/pg_restore.sgml @@ -109,7 +109,8 @@ Clean (drop) database objects before recreating them. - (This might generate some harmless error messages, if any objects + (Unless @@ -489,6 +490,17 @@ + + + + + Use conditional commands (i.e. add an IF EXISTS + clause) when cleaning database objects. This option is not valid + unless + + + diff --git a/src/bin/pg_dump/pg_backup.h b/src/bin/pg_dump/pg_backup.h index 6927968de0..83f7216d50 100644 --- a/src/bin/pg_dump/pg_backup.h +++ b/src/bin/pg_dump/pg_backup.h @@ -113,6 +113,7 @@ typedef struct _restoreOptions char *superuser; /* Username to use as superuser */ char *use_role; /* Issue SET ROLE to this */ int dropSchema; + int if_exists; const char *filename; int dataOnly; int schemaOnly; diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c index 46699a2d14..946454019b 100644 --- a/src/bin/pg_dump/pg_backup_archiver.c +++ b/src/bin/pg_dump/pg_backup_archiver.c @@ -413,8 +413,77 @@ RestoreArchive(Archive *AHX) /* Select owner and schema as necessary */ _becomeOwner(AH, te); _selectOutputSchema(AH, te->namespace); - /* Drop it */ - ahprintf(AH, "%s", te->dropStmt); + + /* + * Now emit the DROP command, if the object has one. Note we + * don't necessarily emit it verbatim; at this point we add an + * appropriate IF EXISTS clause, if the user requested it. + */ + if (*te->dropStmt != '\0') + { + if (!ropt->if_exists) + { + /* No --if-exists? Then just use the original */ + ahprintf(AH, "%s", te->dropStmt); + } + 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 + */ + 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 + { + 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 = '\0'; + appendPQExpBuffer(ftStmt, "%s%s IF EXISTS%s", + dropStmt, buffer, + mark + strlen(buffer)); + } + + ahprintf(AH, "%s", ftStmt->data); + + destroyPQExpBuffer(ftStmt); + + pg_free(dropStmtPtr); + } + } } } diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c index 770e97dce9..f5a6bbb723 100644 --- a/src/bin/pg_dump/pg_dump.c +++ b/src/bin/pg_dump/pg_dump.c @@ -132,6 +132,7 @@ static int binary_upgrade = 0; static int disable_dollar_quoting = 0; static int dump_inserts = 0; static int column_inserts = 0; +static int if_exists = 0; static int no_security_labels = 0; static int no_synchronized_snapshots = 0; static int no_unlogged_table_data = 0; @@ -345,6 +346,7 @@ main(int argc, char **argv) {"disable-dollar-quoting", no_argument, &disable_dollar_quoting, 1}, {"disable-triggers", no_argument, &disable_triggers, 1}, {"exclude-table-data", required_argument, NULL, 4}, + {"if-exists", no_argument, &if_exists, 1}, {"inserts", no_argument, &dump_inserts, 1}, {"lock-wait-timeout", required_argument, NULL, 2}, {"no-tablespaces", no_argument, &outputNoTablespaces, 1}, @@ -573,6 +575,9 @@ main(int argc, char **argv) exit_nicely(1); } + if (if_exists && !outputClean) + exit_horribly(NULL, "option --if-exists requires -c/--clean option\n"); + /* Identify archive format to emit */ archiveFormat = parseArchiveFormat(format, &archiveMode); @@ -805,6 +810,7 @@ main(int argc, char **argv) ropt->dropSchema = outputClean; ropt->dataOnly = dataOnly; ropt->schemaOnly = schemaOnly; + ropt->if_exists = if_exists; ropt->dumpSections = dumpSections; ropt->aclsSkip = aclsSkip; ropt->superuser = outputSuperuser; @@ -886,6 +892,7 @@ help(const char *progname) printf(_(" --disable-dollar-quoting disable dollar quoting, use SQL standard quoting\n")); printf(_(" --disable-triggers disable triggers during data-only restore\n")); printf(_(" --exclude-table-data=TABLE do NOT dump data for the named table(s)\n")); + printf(_(" --if-exists use IF EXISTS when dropping objects\n")); printf(_(" --inserts dump data as INSERT commands, rather than COPY\n")); printf(_(" --no-security-labels do not dump security label assignments\n")); printf(_(" --no-synchronized-snapshots do not use synchronized snapshots in parallel jobs\n")); diff --git a/src/bin/pg_dump/pg_dumpall.c b/src/bin/pg_dump/pg_dumpall.c index 193c1a0c38..f7c610deeb 100644 --- a/src/bin/pg_dump/pg_dumpall.c +++ b/src/bin/pg_dump/pg_dumpall.c @@ -73,6 +73,7 @@ static int binary_upgrade = 0; static int column_inserts = 0; static int disable_dollar_quoting = 0; static int disable_triggers = 0; +static int if_exists = 0; static int inserts = 0; static int no_tablespaces = 0; static int use_setsessauth = 0; @@ -119,6 +120,7 @@ main(int argc, char *argv[]) {"column-inserts", no_argument, &column_inserts, 1}, {"disable-dollar-quoting", no_argument, &disable_dollar_quoting, 1}, {"disable-triggers", no_argument, &disable_triggers, 1}, + {"if-exists", no_argument, &if_exists, 1}, {"inserts", no_argument, &inserts, 1}, {"lock-wait-timeout", required_argument, NULL, 2}, {"no-tablespaces", no_argument, &no_tablespaces, 1}, @@ -334,6 +336,13 @@ main(int argc, char *argv[]) exit_nicely(1); } + if (if_exists && !output_clean) + { + fprintf(stderr, _("%s: option --if-exists requires -c/--clean option\n"), + progname); + exit_nicely(1); + } + if (roles_only && tablespaces_only) { fprintf(stderr, _("%s: options -r/--roles-only and -t/--tablespaces-only cannot be used together\n"), @@ -564,6 +573,7 @@ help(void) printf(_(" --column-inserts dump data as INSERT commands with column names\n")); printf(_(" --disable-dollar-quoting disable dollar quoting, use SQL standard quoting\n")); printf(_(" --disable-triggers disable triggers during data-only restore\n")); + printf(_(" --if-exists use IF EXISTS when dropping objects\n")); printf(_(" --inserts dump data as INSERT commands, rather than COPY\n")); printf(_(" --no-security-labels do not dump security label assignments\n")); printf(_(" --no-tablespaces do not dump tablespace assignments\n")); @@ -624,7 +634,9 @@ dropRoles(PGconn *conn) rolename = PQgetvalue(res, i, i_rolname); - fprintf(OPF, "DROP ROLE %s;\n", fmtId(rolename)); + fprintf(OPF, "DROP ROLE %s%s;\n", + if_exists ? "IF EXISTS " : "", + fmtId(rolename)); } PQclear(res); @@ -994,7 +1006,9 @@ dropTablespaces(PGconn *conn) { char *spcname = PQgetvalue(res, i, 0); - fprintf(OPF, "DROP TABLESPACE %s;\n", fmtId(spcname)); + fprintf(OPF, "DROP TABLESPACE %s%s;\n", + if_exists ? "IF EXISTS " : "", + fmtId(spcname)); } PQclear(res); @@ -1148,7 +1162,9 @@ dropDBs(PGconn *conn) if (strcmp(dbname, "template1") != 0 && strcmp(dbname, "postgres") != 0) { - fprintf(OPF, "DROP DATABASE %s;\n", fmtId(dbname)); + fprintf(OPF, "DROP DATABASE %s%s;\n", + if_exists ? "IF EXISTS " : "", + fmtId(dbname)); } } diff --git a/src/bin/pg_dump/pg_restore.c b/src/bin/pg_dump/pg_restore.c index df9477b69f..f7f3f51ed3 100644 --- a/src/bin/pg_dump/pg_restore.c +++ b/src/bin/pg_dump/pg_restore.c @@ -70,6 +70,7 @@ main(int argc, char **argv) Archive *AH; char *inputFileSpec; static int disable_triggers = 0; + static int if_exists = 0; static int no_data_for_failed_tables = 0; static int outputNoTablespaces = 0; static int use_setsessauth = 0; @@ -110,6 +111,7 @@ main(int argc, char **argv) * the following options don't have an equivalent short option letter */ {"disable-triggers", no_argument, &disable_triggers, 1}, + {"if-exists", no_argument, &if_exists, 1}, {"no-data-for-failed-tables", no_argument, &no_data_for_failed_tables, 1}, {"no-tablespaces", no_argument, &outputNoTablespaces, 1}, {"role", required_argument, NULL, 2}, @@ -336,6 +338,14 @@ main(int argc, char **argv) opts->use_setsessauth = use_setsessauth; opts->no_security_labels = no_security_labels; + if (if_exists && !opts->dropSchema) + { + fprintf(stderr, _("%s: option --if-exists requires -c/--clean option\n"), + progname); + exit_nicely(1); + } + opts->if_exists = if_exists; + if (opts->formatName) { switch (opts->formatName[0]) @@ -450,6 +460,7 @@ usage(const char *progname) printf(_(" -x, --no-privileges skip restoration of access privileges (grant/revoke)\n")); printf(_(" -1, --single-transaction restore as a single transaction\n")); printf(_(" --disable-triggers disable triggers during data-only restore\n")); + printf(_(" --if-exists use IF EXISTS when dropping objects\n")); printf(_(" --no-data-for-failed-tables do not restore data of tables that could not be\n" " created\n")); printf(_(" --no-security-labels do not restore security labels\n"));