Postpone calls of unsafe server-side functions in pg_dump.

Avoid calling pg_get_partkeydef(), pg_get_expr(relpartbound),
and regtypeout until we have lock on the relevant tables.
The existing coding is at serious risk of failure if there
are any concurrent DROP TABLE commands going on --- including
drops of other sessions' temp tables.

Arguably this is a bug fix that should be back-patched, but it's
moderately invasive and we've not had all that many complaints
about such failures.  Let's just put it in HEAD for now.

Discussion: https://postgr.es/m/2273648.1634764485@sss.pgh.pa.us
Discussion: https://postgr.es/m/7d7eb6128f40401d81b3b7a898b6b4de@W2012-02.nidsa.loc

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 75ea57266e2ad2639a0791f20c914773884e4377..294f8fcbbb7d6008040b3a9f4153fc794fd464e0 100644 (file)
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -6272,20 +6272,23 @@ getTables(Archive *fout, int *numTables)
        int                     i_is_identity_sequence;
        int                     i_relacl;
        int                     i_acldefault;
-       int                     i_partkeydef;
        int                     i_ispartition;
-       int                     i_partbound;
 
        /*
         * Find all the tables and table-like objects.
         *
+        * We must fetch all tables in this phase because otherwise we cannot
+        * correctly identify inherited columns, owned sequences, etc.
+        *
         * We include system catalogs, so that we can work if a user table is
         * defined to inherit from a system catalog (pretty weird, but...)
         *
         * Note: in this phase we should collect only a minimal amount of
         * information about each table, basically just enough to decide if it is
-        * interesting. We must fetch all tables in this phase because otherwise
-        * we cannot correctly identify inherited columns, owned sequences, etc.
+        * interesting.  In particular, since we do not yet have lock on any user
+        * table, we MUST NOT invoke any server-side data collection functions
+        * (for instance, pg_get_partkeydef()).  Those are likely to fail or give
+        * wrong answers if any concurrent DDL is happening.
         */
 
        appendPQExpBuffer(query,
@@ -6379,10 +6382,10 @@ getTables(Archive *fout, int *numTables)
 
        if (fout->remoteVersion >= 90000)
                appendPQExpBufferStr(query,
-                                                        "CASE WHEN c.reloftype <> 0 THEN c.reloftype::pg_catalog.regtype ELSE NULL END AS reloftype, ");
+                                                        "c.reloftype, ");
        else
                appendPQExpBufferStr(query,
-                                                        "NULL AS reloftype, ");
+                                                        "0 AS reloftype, ");
 
        if (fout->remoteVersion >= 90100)
                appendPQExpBufferStr(query,
@@ -6423,14 +6426,10 @@ getTables(Archive *fout, int *numTables)
 
        if (fout->remoteVersion >= 100000)
                appendPQExpBufferStr(query,
-                                                        "pg_get_partkeydef(c.oid) AS partkeydef, "
-                                                        "c.relispartition AS ispartition, "
-                                                        "pg_get_expr(c.relpartbound, c.oid) AS partbound ");
+                                                        "c.relispartition AS ispartition ");
        else
                appendPQExpBufferStr(query,
-                                                        "NULL AS partkeydef, "
-                                                        "false AS ispartition, "
-                                                        "NULL AS partbound ");
+                                                        "false AS ispartition ");
 
        /*
         * Left join to pg_depend to pick up dependency info linking sequences to
@@ -6539,9 +6538,7 @@ getTables(Archive *fout, int *numTables)
        i_is_identity_sequence = PQfnumber(res, "is_identity_sequence");
        i_relacl = PQfnumber(res, "relacl");
        i_acldefault = PQfnumber(res, "acldefault");
-       i_partkeydef = PQfnumber(res, "partkeydef");
        i_ispartition = PQfnumber(res, "ispartition");
-       i_partbound = PQfnumber(res, "partbound");
 
        if (dopt->lockWaitTimeout)
        {
@@ -6607,19 +6604,14 @@ getTables(Archive *fout, int *numTables)
                else
                        tblinfo[i].checkoption = pg_strdup(PQgetvalue(res, i, i_checkoption));
                tblinfo[i].toast_reloptions = pg_strdup(PQgetvalue(res, i, i_toastreloptions));
-               if (PQgetisnull(res, i, i_reloftype))
-                       tblinfo[i].reloftype = NULL;
-               else
-                       tblinfo[i].reloftype = pg_strdup(PQgetvalue(res, i, i_reloftype));
+               tblinfo[i].reloftype = atooid(PQgetvalue(res, i, i_reloftype));
                tblinfo[i].foreign_server = atooid(PQgetvalue(res, i, i_foreignserver));
                if (PQgetisnull(res, i, i_amname))
                        tblinfo[i].amname = NULL;
                else
                        tblinfo[i].amname = pg_strdup(PQgetvalue(res, i, i_amname));
                tblinfo[i].is_identity_sequence = (strcmp(PQgetvalue(res, i, i_is_identity_sequence), "t") == 0);
-               tblinfo[i].partkeydef = pg_strdup(PQgetvalue(res, i, i_partkeydef));
                tblinfo[i].ispartition = (strcmp(PQgetvalue(res, i, i_ispartition), "t") == 0);
-               tblinfo[i].partbound = pg_strdup(PQgetvalue(res, i, i_partbound));
 
                /* other fields were zeroed above */
 
@@ -15651,12 +15643,34 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
        }
        else
        {
+               char       *partkeydef = NULL;
                char       *ftoptions = NULL;
                char       *srvname = NULL;
                char       *foreign = "";
 
+               /*
+                * Set reltypename, and collect any relkind-specific data that we
+                * didn't fetch during getTables().
+                */
                switch (tbinfo->relkind)
                {
+                       case RELKIND_PARTITIONED_TABLE:
+                               {
+                                       PQExpBuffer query = createPQExpBuffer();
+                                       PGresult   *res;
+
+                                       reltypename = "TABLE";
+
+                                       /* retrieve partition key definition */
+                                       appendPQExpBuffer(query,
+                                                                         "SELECT pg_get_partkeydef('%u')",
+                                                                         tbinfo->dobj.catId.oid);
+                                       res = ExecuteSqlQueryForSingleRow(fout, query->data);
+                                       partkeydef = pg_strdup(PQgetvalue(res, 0, 0));
+                                       PQclear(res);
+                                       destroyPQExpBuffer(query);
+                                       break;
+                               }
                        case RELKIND_FOREIGN_TABLE:
                                {
                                        PQExpBuffer query = createPQExpBuffer();
@@ -15696,6 +15710,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                                break;
                        default:
                                reltypename = "TABLE";
+                               break;
                }
 
                numParents = tbinfo->numParents;
@@ -15717,8 +15732,10 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                 * Attach to type, if reloftype; except in case of a binary upgrade,
                 * we dump the table normally and attach it to the type afterward.
                 */
-               if (tbinfo->reloftype && !dopt->binary_upgrade)
-                       appendPQExpBuffer(q, " OF %s", tbinfo->reloftype);
+               if (OidIsValid(tbinfo->reloftype) && !dopt->binary_upgrade)
+                       appendPQExpBuffer(q, " OF %s",
+                                                         getFormattedTypeName(fout, tbinfo->reloftype,
+                                                                                                  zeroIsError));
 
                if (tbinfo->relkind != RELKIND_MATVIEW)
                {
@@ -15756,7 +15773,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                                         * Skip column if fully defined by reloftype, except in
                                         * binary upgrade
                                         */
-                                       if (tbinfo->reloftype && !print_default && !print_notnull &&
+                                       if (OidIsValid(tbinfo->reloftype) &&
+                                               !print_default && !print_notnull &&
                                                !dopt->binary_upgrade)
                                                continue;
 
@@ -15789,7 +15807,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                                         * table ('OF type_name'), but in binary-upgrade mode,
                                         * print it in that case too.
                                         */
-                                       if (dopt->binary_upgrade || !tbinfo->reloftype)
+                                       if (dopt->binary_upgrade || !OidIsValid(tbinfo->reloftype))
                                        {
                                                appendPQExpBuffer(q, " %s",
                                                                                  tbinfo->atttypnames[j]);
@@ -15852,7 +15870,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 
                        if (actual_atts)
                                appendPQExpBufferStr(q, "\n)");
-                       else if (!(tbinfo->reloftype && !dopt->binary_upgrade))
+                       else if (!(OidIsValid(tbinfo->reloftype) && !dopt->binary_upgrade))
                        {
                                /*
                                 * No attributes? we must have a parenthesized attribute list,
@@ -15881,7 +15899,7 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                        }
 
                        if (tbinfo->relkind == RELKIND_PARTITIONED_TABLE)
-                               appendPQExpBuffer(q, "\nPARTITION BY %s", tbinfo->partkeydef);
+                               appendPQExpBuffer(q, "\nPARTITION BY %s", partkeydef);
 
                        if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
                                appendPQExpBuffer(q, "\nSERVER %s", fmtId(srvname));
@@ -16064,12 +16082,13 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                                }
                        }
 
-                       if (tbinfo->reloftype)
+                       if (OidIsValid(tbinfo->reloftype))
                        {
                                appendPQExpBufferStr(q, "\n-- For binary upgrade, set up typed tables this way.\n");
                                appendPQExpBuffer(q, "ALTER TABLE ONLY %s OF %s;\n",
                                                                  qualrelname,
-                                                                 tbinfo->reloftype);
+                                                                 getFormattedTypeName(fout, tbinfo->reloftype,
+                                                                                                          zeroIsError));
                        }
                }
 
@@ -16242,6 +16261,8 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
                                                                  tbinfo->attfdwoptions[j]);
                }                                               /* end loop over columns */
 
+               if (partkeydef)
+                       free(partkeydef);
                if (ftoptions)
                        free(ftoptions);
                if (srvname)
@@ -16358,6 +16379,8 @@ dumpTableAttach(Archive *fout, const TableAttachInfo *attachinfo)
 {
        DumpOptions *dopt = fout->dopt;
        PQExpBuffer q;
+       PGresult   *res;
+       char       *partbound;
 
        /* Do nothing in data-only dump */
        if (dopt->dataOnly)
@@ -16368,14 +16391,23 @@ dumpTableAttach(Archive *fout, const TableAttachInfo *attachinfo)
 
        q = createPQExpBuffer();
 
-       /* Perform ALTER TABLE on the parent */
+       /* Fetch the partition's partbound */
        appendPQExpBuffer(q,
+                                         "SELECT pg_get_expr(c.relpartbound, c.oid) "
+                                         "FROM pg_class c "
+                                         "WHERE c.oid = '%u'",
+                                         attachinfo->partitionTbl->dobj.catId.oid);
+       res = ExecuteSqlQueryForSingleRow(fout, q->data);
+       partbound = PQgetvalue(res, 0, 0);
+
+       /* Perform ALTER TABLE on the parent */
+       printfPQExpBuffer(q,
                                          "ALTER TABLE ONLY %s ",
                                          fmtQualifiedDumpable(attachinfo->parentTbl));
        appendPQExpBuffer(q,
                                          "ATTACH PARTITION %s %s;\n",
                                          fmtQualifiedDumpable(attachinfo->partitionTbl),
-                                         attachinfo->partitionTbl->partbound);
+                                         partbound);
 
        /*
         * There is no point in creating a drop query as the drop is done by table
@@ -16392,6 +16424,7 @@ dumpTableAttach(Archive *fout, const TableAttachInfo *attachinfo)
                                                          .section = SECTION_PRE_DATA,
                                                          .createStmt = q->data));
 
+       PQclear(res);
        destroyPQExpBuffer(q);
 }
 

diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index b21b91f8bc9cba766059d95a95d7bee818d9f37c..291b880a9783c7d63268cd5cf4aa2333b5fcdfa8 100644 (file)
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -308,7 +308,7 @@ typedef struct _tableInfo
        uint32          toast_minmxid;  /* toast table's relminmxid */
        int                     ncheck;                 /* # of CHECK expressions */
        Oid                     reltype;                /* OID of table's composite type, if any */
-       char       *reloftype;          /* underlying type for typed table */
+       Oid                     reloftype;              /* underlying type for typed table */
        Oid                     foreign_server; /* foreign server oid, if applicable */
        /* these two are set only if table is a sequence owned by a column: */
        Oid                     owning_tab;             /* OID of table owning sequence */
@@ -347,8 +347,6 @@ typedef struct _tableInfo
        bool       *inhNotNull;         /* true if NOT NULL is inherited */
        struct _attrDefInfo **attrdefs; /* DEFAULT expressions */
        struct _constraintInfo *checkexprs; /* CHECK constraints */
-       char       *partkeydef;         /* partition key definition */
-       char       *partbound;          /* partition bound definition */
        bool            needs_override; /* has GENERATED ALWAYS AS IDENTITY */
        char       *amname;                     /* relation access method */