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Commit43d3fbe

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Clean up some minor inefficiencies in parallel dump/restore.
Parallel dump did a totally pointless query to find out the name of eachtable to be dumped, which it already knows. Parallel restore runs issuedlots of redundant SET commands because _doSetFixedOutputState() was invokedonce per TOC item rather than just once at connection start. While theextra queries are insignificant if you're dumping or restoring largetables, it still seems worth getting rid of them.Also, give the responsibility for selecting the right client_encoding fora parallel dump worker to setup_connection() where it naturally belongs,instead of having ad-hoc code for that in CloneArchive(). And fix someminor bugs like use of strdup() where pg_strdup() would be safer.Back-patch to 9.3, mostly to keep the branches in sync in an area thatwe're still finding bugs in.Discussion: <5086.1464793073@sss.pgh.pa.us>
1 parent47215c1 commit43d3fbe

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3 files changed

+34
-50
lines changed

3 files changed

+34
-50
lines changed

‎src/bin/pg_dump/parallel.c

Lines changed: 1 addition & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -801,7 +801,6 @@ IsEveryWorkerIdle(ParallelState *pstate)
801801
staticvoid
802802
lockTableForWorker(ArchiveHandle*AH,TocEntry*te)
803803
{
804-
Archive*AHX= (Archive*)AH;
805804
constchar*qualId;
806805
PQExpBufferquery;
807806
PGresult*res;
@@ -812,33 +811,10 @@ lockTableForWorker(ArchiveHandle *AH, TocEntry *te)
812811

813812
query=createPQExpBuffer();
814813

815-
/*
816-
* XXX this is an unbelievably expensive substitute for knowing how to dig
817-
* a table name out of a TocEntry.
818-
*/
819-
appendPQExpBuffer(query,
820-
"SELECT pg_namespace.nspname,"
821-
" pg_class.relname "
822-
" FROM pg_class "
823-
" JOIN pg_namespace on pg_namespace.oid = relnamespace "
824-
" WHERE pg_class.oid = %u",te->catalogId.oid);
825-
826-
res=PQexec(AH->connection,query->data);
827-
828-
if (!res||PQresultStatus(res)!=PGRES_TUPLES_OK)
829-
exit_horribly(modulename,
830-
"could not get relation name for OID %u: %s\n",
831-
te->catalogId.oid,PQerrorMessage(AH->connection));
832-
833-
resetPQExpBuffer(query);
834-
835-
qualId=fmtQualifiedId(AHX->remoteVersion,
836-
PQgetvalue(res,0,0),
837-
PQgetvalue(res,0,1));
814+
qualId=fmtQualifiedId(AH->public.remoteVersion,te->namespace,te->tag);
838815

839816
appendPQExpBuffer(query,"LOCK TABLE %s IN ACCESS SHARE MODE NOWAIT",
840817
qualId);
841-
PQclear(res);
842818

843819
res=PQexec(AH->connection,query->data);
844820

‎src/bin/pg_dump/pg_backup_archiver.c

Lines changed: 7 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -3831,6 +3831,7 @@ restore_toc_entries_postfork(ArchiveHandle *AH, TocEntry *pending_list)
38313831
ropt->pghost,ropt->pgport,ropt->username,
38323832
ropt->promptPassword);
38333833

3834+
/* re-establish fixed state */
38343835
_doSetFixedOutputState(AH);
38353836

38363837
/*
@@ -4009,10 +4010,9 @@ parallel_restore(ParallelArgs *args)
40094010
TocEntry*te=args->te;
40104011
intstatus;
40114012

4012-
_doSetFixedOutputState(AH);
4013-
40144013
Assert(AH->connection!=NULL);
40154014

4015+
/* Count only errors associated with this TOC entry */
40164016
AH->public.n_errors=0;
40174017

40184018
/* Restore the TOC item */
@@ -4381,18 +4381,21 @@ CloneArchive(ArchiveHandle *AH)
43814381
RestoreOptions*ropt=AH->public.ropt;
43824382

43834383
Assert(AH->connection==NULL);
4384+
43844385
/* this also sets clone->connection */
43854386
ConnectDatabase((Archive*)clone,ropt->dbname,
43864387
ropt->pghost,ropt->pgport,ropt->username,
43874388
ropt->promptPassword);
4389+
4390+
/* re-establish fixed state */
4391+
_doSetFixedOutputState(clone);
43884392
}
43894393
else
43904394
{
43914395
char*dbname;
43924396
char*pghost;
43934397
char*pgport;
43944398
char*username;
4395-
constchar*encname;
43964399

43974400
Assert(AH->connection!=NULL);
43984401

@@ -4406,18 +4409,11 @@ CloneArchive(ArchiveHandle *AH)
44064409
pghost=PQhost(AH->connection);
44074410
pgport=PQport(AH->connection);
44084411
username=PQuser(AH->connection);
4409-
encname=pg_encoding_to_char(AH->public.encoding);
44104412

44114413
/* this also sets clone->connection */
44124414
ConnectDatabase((Archive*)clone,dbname,pghost,pgport,username,TRI_NO);
44134415

4414-
/*
4415-
* Set the same encoding, whatever we set here is what we got from
4416-
* pg_encoding_to_char(), so we really shouldn't run into an error
4417-
* setting that very same value. Also see the comment in
4418-
* SetupConnection().
4419-
*/
4420-
PQsetClientEncoding(clone->connection,encname);
4416+
/* setupDumpWorker will fix up connection state */
44214417
}
44224418

44234419
/* Let the format-specific code have a chance too */

‎src/bin/pg_dump/pg_dump.c

Lines changed: 26 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -935,10 +935,7 @@ setup_connection(Archive *AH, const char *dumpencoding,
935935
constchar*std_strings;
936936

937937
/*
938-
* Set the client encoding if requested. If dumpencoding == NULL then
939-
* either it hasn't been requested or we're a cloned connection and then
940-
* this has already been set in CloneArchive according to the original
941-
* connection encoding.
938+
* Set the client encoding if requested.
942939
*/
943940
if (dumpencoding)
944941
{
@@ -956,7 +953,11 @@ setup_connection(Archive *AH, const char *dumpencoding,
956953
std_strings=PQparameterStatus(conn,"standard_conforming_strings");
957954
AH->std_strings= (std_strings&&strcmp(std_strings,"on")==0);
958955

959-
/* Set the role if requested */
956+
/*
957+
* Set the role if requested. In a parallel dump worker, we'll be passed
958+
* use_role == NULL, but AH->use_role is already set (if user specified it
959+
* originally) and we should use that.
960+
*/
960961
if (!use_role&&AH->use_role)
961962
use_role=AH->use_role;
962963

@@ -969,9 +970,9 @@ setup_connection(Archive *AH, const char *dumpencoding,
969970
ExecuteSqlStatement(AH,query->data);
970971
destroyPQExpBuffer(query);
971972

972-
/* savethis for later useon parallelconnections */
973+
/* saveit forpossiblelater useby parallelworkers */
973974
if (!AH->use_role)
974-
AH->use_role=strdup(use_role);
975+
AH->use_role=pg_strdup(use_role);
975976
}
976977

977978
/* Set the datestyle to ISO to ensure the dump's portability */
@@ -1057,11 +1058,12 @@ setup_connection(Archive *AH, const char *dumpencoding,
10571058
"SET TRANSACTION ISOLATION LEVEL SERIALIZABLE");
10581059

10591060
/*
1060-
* define an export snapshot, either chosen by user or needed for parallel
1061-
* dump.
1061+
* If user specified a snapshot to use, select that. In a parallel dump
1062+
* worker, we'll be passed dumpsnapshot == NULL, but AH->sync_snapshot_id
1063+
* is already set (if the server can handle it) and we should use that.
10621064
*/
10631065
if (dumpsnapshot)
1064-
AH->sync_snapshot_id=strdup(dumpsnapshot);
1066+
AH->sync_snapshot_id=pg_strdup(dumpsnapshot);
10651067

10661068
if (AH->sync_snapshot_id)
10671069
{
@@ -1087,21 +1089,31 @@ setup_connection(Archive *AH, const char *dumpencoding,
10871089
}
10881090
}
10891091

1092+
/* Set up connection for a parallel worker process */
10901093
staticvoid
1091-
setupDumpWorker(Archive*AHX)
1094+
setupDumpWorker(Archive*AH)
10921095
{
1093-
setup_connection(AHX,NULL,NULL,NULL);
1096+
/*
1097+
* We want to re-select all the same values the master connection is
1098+
* using. We'll have inherited directly-usable values in
1099+
* AH->sync_snapshot_id and AH->use_role, but we need to translate the
1100+
* inherited encoding value back to a string to pass to setup_connection.
1101+
*/
1102+
setup_connection(AH,
1103+
pg_encoding_to_char(AH->encoding),
1104+
NULL,
1105+
NULL);
10941106
}
10951107

10961108
staticchar*
10971109
get_synchronized_snapshot(Archive*fout)
10981110
{
1099-
char*query="SELECT pg_export_snapshot()";
1111+
char*query="SELECTpg_catalog.pg_export_snapshot()";
11001112
char*result;
11011113
PGresult*res;
11021114

11031115
res=ExecuteSqlQueryForSingleRow(fout,query);
1104-
result=strdup(PQgetvalue(res,0,0));
1116+
result=pg_strdup(PQgetvalue(res,0,0));
11051117
PQclear(res);
11061118

11071119
returnresult;

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