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 */