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Commite0f05cd

Browse files
committed
Improve some ancient, crufty code in bootstrap + initdb.
At some point back in the last century, somebody felt that readingall of pg_type twice was cheaper, or at least easier, than usingrepalloc() to resize the Typ[] array dynamically. That seems like anentirely wacko proposition, so rewrite the code to do it the otherway. (To add insult to injury, there were two not-quite-identicalcopies of said code.)initdb.c's readfile() function had the same disease of preferringto do double the I/O to avoid resizing its output array. Here,we can make things easier by using the just-invented pg_get_line()function to handle reading individual lines without a predeterminednotion of how long they are.On my machine, it's difficult to detect any net change in theoverall runtime of initdb from these changes; but they shouldhelp on slower buildfarm machines (especially since a buildfarmcycle involves a lot of initdb's these days).My attention was drawn to these places by scan-build complaints,but on inspection they needed a lot more work than just suppressingdead stores :-(
1 parenta5cc4da commite0f05cd

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2 files changed

+74
-91
lines changed

2 files changed

+74
-91
lines changed

‎src/backend/bootstrap/bootstrap.c

Lines changed: 60 additions & 59 deletions
Original file line numberDiff line numberDiff line change
@@ -53,14 +53,12 @@
5353
uint32bootstrap_data_checksum_version=0;/* No checksum */
5454

5555

56-
#defineALLOC(t,c) \
57-
((t *) MemoryContextAllocZero(TopMemoryContext, (unsigned)(c) * sizeof(t)))
58-
5956
staticvoidCheckerModeMain(void);
6057
staticvoidBootstrapModeMain(void);
6158
staticvoidbootstrap_signals(void);
6259
staticvoidShutdownAuxiliaryProcess(intcode,Datumarg);
6360
staticForm_pg_attributeAllocateAttribute(void);
61+
staticvoidpopulate_typ_array(void);
6462
staticOidgettype(char*type);
6563
staticvoidcleanup(void);
6664

@@ -583,46 +581,24 @@ ShutdownAuxiliaryProcess(int code, Datum arg)
583581

584582
/* ----------------
585583
*boot_openrel
584+
*
585+
* Execute BKI OPEN command.
586586
* ----------------
587587
*/
588588
void
589589
boot_openrel(char*relname)
590590
{
591591
inti;
592-
structtypmap**app;
593-
Relationrel;
594-
TableScanDescscan;
595-
HeapTupletup;
596592

597593
if (strlen(relname) >=NAMEDATALEN)
598594
relname[NAMEDATALEN-1]='\0';
599595

596+
/*
597+
* pg_type must be filled before any OPEN command is executed, hence we
598+
* can now populate the Typ array if we haven't yet.
599+
*/
600600
if (Typ==NULL)
601-
{
602-
/* We can now load the pg_type data */
603-
rel=table_open(TypeRelationId,NoLock);
604-
scan=table_beginscan_catalog(rel,0,NULL);
605-
i=0;
606-
while ((tup=heap_getnext(scan,ForwardScanDirection))!=NULL)
607-
++i;
608-
table_endscan(scan);
609-
app=Typ=ALLOC(structtypmap*,i+1);
610-
while (i-->0)
611-
*app++=ALLOC(structtypmap,1);
612-
*app=NULL;
613-
scan=table_beginscan_catalog(rel,0,NULL);
614-
app=Typ;
615-
while ((tup=heap_getnext(scan,ForwardScanDirection))!=NULL)
616-
{
617-
(*app)->am_oid= ((Form_pg_type)GETSTRUCT(tup))->oid;
618-
memcpy((char*)&(*app)->am_typ,
619-
(char*)GETSTRUCT(tup),
620-
sizeof((*app)->am_typ));
621-
app++;
622-
}
623-
table_endscan(scan);
624-
table_close(rel,NoLock);
625-
}
601+
populate_typ_array();
626602

627603
if (boot_reldesc!=NULL)
628604
closerel(NULL);
@@ -889,6 +865,52 @@ cleanup(void)
889865
closerel(NULL);
890866
}
891867

868+
/* ----------------
869+
*populate_typ_array
870+
*
871+
* Load the Typ array by reading pg_type.
872+
* ----------------
873+
*/
874+
staticvoid
875+
populate_typ_array(void)
876+
{
877+
Relationrel;
878+
TableScanDescscan;
879+
HeapTupletup;
880+
intnalloc;
881+
inti;
882+
883+
Assert(Typ==NULL);
884+
885+
nalloc=512;
886+
Typ= (structtypmap**)
887+
MemoryContextAlloc(TopMemoryContext,nalloc*sizeof(structtypmap*));
888+
889+
rel=table_open(TypeRelationId,NoLock);
890+
scan=table_beginscan_catalog(rel,0,NULL);
891+
i=0;
892+
while ((tup=heap_getnext(scan,ForwardScanDirection))!=NULL)
893+
{
894+
Form_pg_typetypForm= (Form_pg_type)GETSTRUCT(tup);
895+
896+
/* make sure there will be room for a trailing NULL pointer */
897+
if (i >=nalloc-1)
898+
{
899+
nalloc *=2;
900+
Typ= (structtypmap**)
901+
repalloc(Typ,nalloc*sizeof(structtypmap*));
902+
}
903+
Typ[i]= (structtypmap*)
904+
MemoryContextAlloc(TopMemoryContext,sizeof(structtypmap));
905+
Typ[i]->am_oid=typForm->oid;
906+
memcpy(&(Typ[i]->am_typ),typForm,sizeof(Typ[i]->am_typ));
907+
i++;
908+
}
909+
Typ[i]=NULL;/* Fill trailing NULL pointer */
910+
table_endscan(scan);
911+
table_close(rel,NoLock);
912+
}
913+
892914
/* ----------------
893915
*gettype
894916
*
@@ -903,14 +925,10 @@ cleanup(void)
903925
staticOid
904926
gettype(char*type)
905927
{
906-
inti;
907-
Relationrel;
908-
TableScanDescscan;
909-
HeapTupletup;
910-
structtypmap**app;
911-
912928
if (Typ!=NULL)
913929
{
930+
structtypmap**app;
931+
914932
for (app=Typ;*app!=NULL;app++)
915933
{
916934
if (strncmp(NameStr((*app)->am_typ.typname),type,NAMEDATALEN)==0)
@@ -922,33 +940,16 @@ gettype(char *type)
922940
}
923941
else
924942
{
943+
inti;
944+
925945
for (i=0;i<n_types;i++)
926946
{
927947
if (strncmp(type,TypInfo[i].name,NAMEDATALEN)==0)
928948
returni;
929949
}
950+
/* Not in TypInfo, so we'd better be able to read pg_type now */
930951
elog(DEBUG4,"external type: %s",type);
931-
rel=table_open(TypeRelationId,NoLock);
932-
scan=table_beginscan_catalog(rel,0,NULL);
933-
i=0;
934-
while ((tup=heap_getnext(scan,ForwardScanDirection))!=NULL)
935-
++i;
936-
table_endscan(scan);
937-
app=Typ=ALLOC(structtypmap*,i+1);
938-
while (i-->0)
939-
*app++=ALLOC(structtypmap,1);
940-
*app=NULL;
941-
scan=table_beginscan_catalog(rel,0,NULL);
942-
app=Typ;
943-
while ((tup=heap_getnext(scan,ForwardScanDirection))!=NULL)
944-
{
945-
(*app)->am_oid= ((Form_pg_type)GETSTRUCT(tup))->oid;
946-
memmove((char*)&(*app++)->am_typ,
947-
(char*)GETSTRUCT(tup),
948-
sizeof((*app)->am_typ));
949-
}
950-
table_endscan(scan);
951-
table_close(rel,NoLock);
952+
populate_typ_array();
952953
returngettype(type);
953954
}
954955
elog(ERROR,"unrecognized type \"%s\"",type);

‎src/bin/initdb/initdb.c

Lines changed: 14 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -468,54 +468,36 @@ filter_lines_with_token(char **lines, const char *token)
468468
staticchar**
469469
readfile(constchar*path)
470470
{
471+
char**result;
471472
FILE*infile;
472-
intmaxlength=1,
473-
linelen=0;
474-
intnlines=0;
473+
intmaxlines;
475474
intn;
476-
char**result;
477-
char*buffer;
478-
intc;
475+
char*ln;
479476

480477
if ((infile=fopen(path,"r"))==NULL)
481478
{
482479
pg_log_error("could not open file \"%s\" for reading: %m",path);
483480
exit(1);
484481
}
485482

486-
/* pass over the file twice - the first time to size the result */
483+
maxlines=1024;
484+
result= (char**)pg_malloc(maxlines*sizeof(char*));
487485

488-
while ((c=fgetc(infile))!=EOF)
486+
n=0;
487+
while ((ln=pg_get_line(infile))!=NULL)
489488
{
490-
linelen++;
491-
if (c=='\n')
489+
/* make sure there will be room for a trailing NULL pointer */
490+
if (n >=maxlines-1)
492491
{
493-
nlines++;
494-
if (linelen>maxlength)
495-
maxlength=linelen;
496-
linelen=0;
492+
maxlines *=2;
493+
result= (char**)pg_realloc(result,maxlines*sizeof(char*));
497494
}
498-
}
499-
500-
/* handle last line without a terminating newline (yuck) */
501-
if (linelen)
502-
nlines++;
503-
if (linelen>maxlength)
504-
maxlength=linelen;
505495

506-
/* set up the result and the line buffer */
507-
result= (char**)pg_malloc((nlines+1)*sizeof(char*));
508-
buffer= (char*)pg_malloc(maxlength+1);
509-
510-
/* now reprocess the file and store the lines */
511-
rewind(infile);
512-
n=0;
513-
while (fgets(buffer,maxlength+1,infile)!=NULL&&n<nlines)
514-
result[n++]=pg_strdup(buffer);
496+
result[n++]=ln;
497+
}
498+
result[n]=NULL;
515499

516500
fclose(infile);
517-
free(buffer);
518-
result[n]=NULL;
519501

520502
returnresult;
521503
}

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