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Use a cursor for fetching data in -d or -D mode, so that pg_dump doesn't

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run out of memory with large tables in these modes.  Patch from
Martijn van Oosterhout.
This commit is contained in:
Tom Lane 2001-08-27 20:33:07 +00:00
parent 545c6696a6
commit 814f40cf43
1 changed files with 80 additions and 52 deletions
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36
src/bin/pg_dump/pg_dump.c
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@ -22,7 +22,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.226 2001/08/27 01:09:59 tgl Exp $ * $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.227 2001/08/27 20:33:07 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -400,20 +400,34 @@ dumpClasses_dumpData(Archive *fout, char *oid, void *dctxv)
if (fout->remoteVersion >= 70100) if (fout->remoteVersion >= 70100)
{ {
appendPQExpBuffer(q, "SELECT * FROM ONLY %s", fmtId(classname, force_quotes)); appendPQExpBuffer(q, "DECLARE _pg_dump_cursor CURSOR FOR SELECT * FROM ONLY %s", fmtId(classname, force_quotes));
} else { } else {
appendPQExpBuffer(q, "SELECT * FROM %s", fmtId(classname, force_quotes)); appendPQExpBuffer(q, "DECLARE _pg_dump_cursor CURSOR FOR SELECT * FROM %s", fmtId(classname, force_quotes));
} }
res = PQexec(g_conn, q->data); res = PQexec(g_conn, q->data);
if (!res || if (!res ||
PQresultStatus(res) != PGRES_TUPLES_OK) PQresultStatus(res) != PGRES_COMMAND_OK)
{ {
write_msg(NULL, "dumpClasses(): SQL command failed\n"); write_msg(NULL, "dumpClasses(): SQL command failed\n");
write_msg(NULL, "Error message from server: %s", PQerrorMessage(g_conn)); write_msg(NULL, "Error message from server: %s", PQerrorMessage(g_conn));
write_msg(NULL, "The command was: %s\n", q->data); write_msg(NULL, "The command was: %s\n", q->data);
exit_nicely(); exit_nicely();
} }
do {
PQclear(res);
res = PQexec(g_conn, "FETCH 100 FROM _pg_dump_cursor");
if (!res ||
PQresultStatus(res) != PGRES_TUPLES_OK)
{
write_msg(NULL, "dumpClasses(): SQL command failed\n");
write_msg(NULL, "Error message from server: %s", PQerrorMessage(g_conn));
write_msg(NULL, "The command was: FETCH 100 FROM _pg_dump_cursor\n");
exit_nicely();
}
for (tuple = 0; tuple < PQntuples(res); tuple++) for (tuple = 0; tuple < PQntuples(res); tuple++)
{ {
archprintf(fout, "INSERT INTO %s ", fmtId(classname, force_quotes)); archprintf(fout, "INSERT INTO %s ", fmtId(classname, force_quotes));
@ -470,7 +484,21 @@ dumpClasses_dumpData(Archive *fout, char *oid, void *dctxv)
} }
archprintf(fout, ");\n"); archprintf(fout, ");\n");
} }
} while( PQntuples(res) > 0 );
PQclear(res); PQclear(res);
res = PQexec(g_conn, "CLOSE _pg_dump_cursor");
if (!res ||
PQresultStatus(res) != PGRES_COMMAND_OK)
{
write_msg(NULL, "dumpClasses(): SQL command failed\n");
write_msg(NULL, "Error message from server: %s", PQerrorMessage(g_conn));
write_msg(NULL, "The command was: CLOSE _pg_dump_cursor\n");
exit_nicely();
}
PQclear(res);
destroyPQExpBuffer(q); destroyPQExpBuffer(q);
return 1; return 1;
} }