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Commitc027d84

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Fix memory leaks in record_out() and record_send().
record_out() leaks memory: it fails to free the strings returned by theper-column output functions, and also is careless about detoasted values.This results in a query-lifespan memory leakage when returning compositevalues to the client, because printtup() runs the output functions in thequery-lifespan memory context. Fix it to handle these issues the same wayprinttup() does. Also fix a similar leakage in record_send().(At some point we might want to try to run output functions inshorter-lived memory contexts, so that we don't need a zero-leakage policyfor them. But that would be a significantly more invasive patch, whichdoesn't seem like material for back-patching.)In passing, use appendStringInfoCharMacro instead of appendStringInfoCharin the innermost data-copying loop of record_out, to try to shave a fewcycles from this function's runtime.Per trouble report from Carlos Henrique Reimer. Back-patch to allsupported versions.
1 parent2faab1a commitc027d84

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+40
-12
lines changed

1 file changed

+40
-12
lines changed

‎src/backend/utils/adt/rowtypes.c‎

Lines changed: 40 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,7 @@ typedef struct ColumnIOData
3232
Oidcolumn_type;
3333
Oidtypiofunc;
3434
Oidtypioparam;
35+
booltypisvarlena;
3536
FmgrInfoproc;
3637
}ColumnIOData;
3738

@@ -340,6 +341,7 @@ record_out(PG_FUNCTION_ARGS)
340341
{
341342
ColumnIOData*column_info=&my_extra->columns[i];
342343
Oidcolumn_type=tupdesc->attrs[i]->atttypid;
344+
Datumattr;
343345
char*value;
344346
char*tmp;
345347
boolnq;
@@ -363,17 +365,24 @@ record_out(PG_FUNCTION_ARGS)
363365
*/
364366
if (column_info->column_type!=column_type)
365367
{
366-
booltypIsVarlena;
367-
368368
getTypeOutputInfo(column_type,
369369
&column_info->typiofunc,
370-
&typIsVarlena);
370+
&column_info->typisvarlena);
371371
fmgr_info_cxt(column_info->typiofunc,&column_info->proc,
372372
fcinfo->flinfo->fn_mcxt);
373373
column_info->column_type=column_type;
374374
}
375375

376-
value=OutputFunctionCall(&column_info->proc,values[i]);
376+
/*
377+
* If we have a toasted datum, forcibly detoast it here to avoid
378+
* memory leakage inside the type's output routine.
379+
*/
380+
if (column_info->typisvarlena)
381+
attr=PointerGetDatum(PG_DETOAST_DATUM(values[i]));
382+
else
383+
attr=values[i];
384+
385+
value=OutputFunctionCall(&column_info->proc,attr);
377386

378387
/* Detect whether we need double quotes for this value */
379388
nq= (value[0]=='\0');/* force quotes for empty string */
@@ -392,17 +401,23 @@ record_out(PG_FUNCTION_ARGS)
392401

393402
/* And emit the string */
394403
if (nq)
395-
appendStringInfoChar(&buf,'"');
404+
appendStringInfoCharMacro(&buf,'"');
396405
for (tmp=value;*tmp;tmp++)
397406
{
398407
charch=*tmp;
399408

400409
if (ch=='"'||ch=='\\')
401-
appendStringInfoChar(&buf,ch);
402-
appendStringInfoChar(&buf,ch);
410+
appendStringInfoCharMacro(&buf,ch);
411+
appendStringInfoCharMacro(&buf,ch);
403412
}
404413
if (nq)
405-
appendStringInfoChar(&buf,'"');
414+
appendStringInfoCharMacro(&buf,'"');
415+
416+
pfree(value);
417+
418+
/* Clean up detoasted copy, if any */
419+
if (DatumGetPointer(attr)!=DatumGetPointer(values[i]))
420+
pfree(DatumGetPointer(attr));
406421
}
407422

408423
appendStringInfoChar(&buf,')');
@@ -690,6 +705,7 @@ record_send(PG_FUNCTION_ARGS)
690705
{
691706
ColumnIOData*column_info=&my_extra->columns[i];
692707
Oidcolumn_type=tupdesc->attrs[i]->atttypid;
708+
Datumattr;
693709
bytea*outputbytes;
694710

695711
/* Ignore dropped columns in datatype */
@@ -710,23 +726,35 @@ record_send(PG_FUNCTION_ARGS)
710726
*/
711727
if (column_info->column_type!=column_type)
712728
{
713-
booltypIsVarlena;
714-
715729
getTypeBinaryOutputInfo(column_type,
716730
&column_info->typiofunc,
717-
&typIsVarlena);
731+
&column_info->typisvarlena);
718732
fmgr_info_cxt(column_info->typiofunc,&column_info->proc,
719733
fcinfo->flinfo->fn_mcxt);
720734
column_info->column_type=column_type;
721735
}
722736

723-
outputbytes=SendFunctionCall(&column_info->proc,values[i]);
737+
/*
738+
* If we have a toasted datum, forcibly detoast it here to avoid
739+
* memory leakage inside the type's output routine.
740+
*/
741+
if (column_info->typisvarlena)
742+
attr=PointerGetDatum(PG_DETOAST_DATUM(values[i]));
743+
else
744+
attr=values[i];
745+
746+
outputbytes=SendFunctionCall(&column_info->proc,attr);
724747

725748
/* We assume the result will not have been toasted */
726749
pq_sendint(&buf,VARSIZE(outputbytes)-VARHDRSZ,4);
727750
pq_sendbytes(&buf,VARDATA(outputbytes),
728751
VARSIZE(outputbytes)-VARHDRSZ);
752+
729753
pfree(outputbytes);
754+
755+
/* Clean up detoasted copy, if any */
756+
if (DatumGetPointer(attr)!=DatumGetPointer(values[i]))
757+
pfree(DatumGetPointer(attr));
730758
}
731759

732760
pfree(values);

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