From 814f40cf43fc899e854b2c09219c5285da3eda04 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 27 Aug 2001 20:33:07 +0000
Subject: [PATCH] Use a cursor for fetching data in -d or -D mode, so that
pg_dump doesn't run out of memory with large tables in these modes. Patch
from Martijn van Oosterhout.
---
src/bin/pg_dump/pg_dump.c | 130 +++++++++++++++++++++++---------------
1 file changed, 79 insertions(+), 51 deletions(-)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 6085c241f40..abed81cf825 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -22,7 +22,7 @@
*
*
* 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 $
*
*-------------------------------------------------------------------------
*/
@@ -400,77 +400,105 @@ dumpClasses_dumpData(Archive *fout, char *oid, void *dctxv)
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 {
- 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);
if (!res ||
- PQresultStatus(res) != PGRES_TUPLES_OK)
+ 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: %s\n", q->data);
exit_nicely();
}
- for (tuple = 0; tuple < PQntuples(res); tuple++)
- {
- archprintf(fout, "INSERT INTO %s ", fmtId(classname, force_quotes));
- if (attrNames == true)
+
+ do {
+ PQclear(res);
+
+ res = PQexec(g_conn, "FETCH 100 FROM _pg_dump_cursor");
+ if (!res ||
+ PQresultStatus(res) != PGRES_TUPLES_OK)
{
- resetPQExpBuffer(q);
- appendPQExpBuffer(q, "(");
- for (field = 0; field < PQnfields(res); field++)
- {
- if (field > 0)
- appendPQExpBuffer(q, ",");
- appendPQExpBuffer(q, fmtId(PQfname(res, field), force_quotes));
- }
- appendPQExpBuffer(q, ") ");
- archprintf(fout, "%s", q->data);
+ 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();
}
- archprintf(fout, "VALUES (");
- for (field = 0; field < PQnfields(res); field++)
+
+ for (tuple = 0; tuple < PQntuples(res); tuple++)
{
- if (field > 0)
- archprintf(fout, ",");
- if (PQgetisnull(res, tuple, field))
+ archprintf(fout, "INSERT INTO %s ", fmtId(classname, force_quotes));
+ if (attrNames == true)
{
- archprintf(fout, "NULL");
- continue;
+ resetPQExpBuffer(q);
+ appendPQExpBuffer(q, "(");
+ for (field = 0; field < PQnfields(res); field++)
+ {
+ if (field > 0)
+ appendPQExpBuffer(q, ",");
+ appendPQExpBuffer(q, fmtId(PQfname(res, field), force_quotes));
+ }
+ appendPQExpBuffer(q, ") ");
+ archprintf(fout, "%s", q->data);
}
- switch (PQftype(res, field))
+ archprintf(fout, "VALUES (");
+ for (field = 0; field < PQnfields(res); field++)
{
- case INT2OID:
- case INT4OID:
- case OIDOID: /* int types */
- case FLOAT4OID:
- case FLOAT8OID:/* float types */
- /* These types are printed without quotes */
- archprintf(fout, "%s",
- PQgetvalue(res, tuple, field));
- break;
- case BITOID:
- case VARBITOID:
- archprintf(fout, "B'%s'",
- PQgetvalue(res, tuple, field));
- break;
- default:
-
- /*
- * All other types are printed as string literals,
- * with appropriate escaping of special characters.
- */
- resetPQExpBuffer(q);
- formatStringLiteral(q, PQgetvalue(res, tuple, field), CONV_ALL);
- archprintf(fout, "%s", q->data);
- break;
+ if (field > 0)
+ archprintf(fout, ",");
+ if (PQgetisnull(res, tuple, field))
+ {
+ archprintf(fout, "NULL");
+ continue;
+ }
+ switch (PQftype(res, field))
+ {
+ case INT2OID:
+ case INT4OID:
+ case OIDOID: /* int types */
+ case FLOAT4OID:
+ case FLOAT8OID:/* float types */
+ /* These types are printed without quotes */
+ archprintf(fout, "%s",
+ PQgetvalue(res, tuple, field));
+ break;
+ case BITOID:
+ case VARBITOID:
+ archprintf(fout, "B'%s'",
+ PQgetvalue(res, tuple, field));
+ break;
+ default:
+
+ /*
+ * All other types are printed as string literals,
+ * with appropriate escaping of special characters.
+ */
+ resetPQExpBuffer(q);
+ formatStringLiteral(q, PQgetvalue(res, tuple, field), CONV_ALL);
+ archprintf(fout, "%s", q->data);
+ break;
+ }
}
+ archprintf(fout, ");\n");
}
- archprintf(fout, ");\n");
+
+ } while( PQntuples(res) > 0 );
+ 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);
return 1;
}
--
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