mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Postpone calls of unsafe server-side functions in pg_dump.

Browse Source 
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
This commit is contained in:
Tom Lane 2021-12-06 12:49:49 -05:00
parent 0c9d84427f
commit e3fcbbd623
2 changed files with 64 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
src/bin/pg_dump/pg_dump.c
View File

@ -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);
}

4
src/bin/pg_dump/pg_dump.h
View File

@ -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 */