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vacuumlo: Use a cursor to limit client-side memory usage.

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This prevents the client from gobbling up too much memory when the
number of large objects to be removed is very large.

Andrew Dunstan, reviewed by Josh Kupershmidt
pull/6/head
Robert Haas 13 years ago
parent 03010366b6
commit 67ccbb080d
1 changed files with 69 additions and 42 deletions
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  1. 111
      contrib/vacuumlo/vacuumlo.c

111
contrib/vacuumlo/vacuumlo.c
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@ -290,74 +290,101 @@ vacuumlo(const char *database, const struct _param * param)
PQclear(res);
buf[0] = '\0';
strcat(buf, "SELECT lo FROM vacuum_l");
strcat(buf,
"DECLARE myportal CURSOR WITH HOLD FOR SELECT lo FROM vacuum_l");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to read temp table:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
fprintf(stderr, "DECLARE CURSOR failed: %s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
snprintf(buf, BUFSIZE, "FETCH FORWARD %ld IN myportal",
param->transaction_limit > 0 ? param->transaction_limit : 1000L);
matched = PQntuples(res);
deleted = 0;
for (i = 0; i < matched; i++)
while (1)
{
Oid lo = atooid(PQgetvalue(res, i, 0));
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
fprintf(stderr, "FETCH FORWARD failed: %s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
if (param->verbose)
matched = PQntuples(res);
if (matched <= 0)
{
fprintf(stdout, "\rRemoving lo %6u ", lo);
fflush(stdout);
/* at end of resultset */
PQclear(res);
break;
}
if (param->dry_run == 0)
for (i = 0; i < matched; i++)
{
if (lo_unlink(conn, lo) < 0)
Oid lo = atooid(PQgetvalue(res, i, 0));
if (param->verbose)
{
fprintf(stdout, "\rRemoving lo %6u ", lo);
fflush(stdout);
}
if (param->dry_run == 0)
{
fprintf(stderr, "\nFailed to remove lo %u: ", lo);
fprintf(stderr, "%s", PQerrorMessage(conn));
if (PQtransactionStatus(conn) == PQTRANS_INERROR)
if (lo_unlink(conn, lo) < 0)
{
success = false;
break;
fprintf(stderr, "\nFailed to remove lo %u: ", lo);
fprintf(stderr, "%s", PQerrorMessage(conn));
if (PQtransactionStatus(conn) == PQTRANS_INERROR)
{
success = false;
PQclear(res);
break;
}
}
else
deleted++;
}
else
deleted++;
}
else
deleted++;
if (param->transaction_limit > 0 &&
(deleted % param->transaction_limit) == 0)
{
res2 = PQexec(conn, "commit");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
if (param->transaction_limit > 0 &&
(deleted % param->transaction_limit) == 0)
{
fprintf(stderr, "Failed to commit transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
res2 = PQexec(conn, "commit");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to commit transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
res2 = PQexec(conn, "begin");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to start transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
res2 = PQexec(conn, "begin");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to start transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
}
PQclear(res);
}
PQclear(res);
/*
* That's all folks!

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