Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Skip to content

Commit 280a77d

Browse files
tglsfdctglsfdc
committed
Code review and cleanup.
1 parent 22c528f commit 280a77d

File tree

2 files changed

+102
-61
lines changed

2 files changed

+102
-61
lines changed

‎contrib/vacuumlo/README.vacuumlo

+18-10
Original file line numberDiff line numberDiff line change
@@ -1,35 +1,43 @@
1-
$Header: /cvsroot/pgsql/contrib/vacuumlo/Attic/README.vacuumlo,v 1.1 2000/06/19 14:02:16 momjian Exp $
1+
$Header: /cvsroot/pgsql/contrib/vacuumlo/Attic/README.vacuumlo,v 1.2 2000/11/21 17:54:21 tgl Exp $
22

33
This is a simple utility that will remove any orphaned large objects out of a
4-
PostgreSQL database.
4+
PostgreSQL database. An orphaned LO is considered to be any LO whose OID
5+
does not appear in any OID data column of the database.
6+
57

68
Compiling
79
--------
810

911
Simply run make. A single executable "vacuumlo" is created.
1012

11-
Useage
12-
------
13+
14+
Usage
15+
-----
1316

1417
vacuumlo [-v] database [db2 ... dbn]
1518

1619
The -v flag outputs some progress messages to stdout.
1720

21+
1822
Method
1923
------
2024

2125
First, it builds a temporary table which contains all of the oid's of the
2226
large objects in that database.
2327

24-
It then scans through any columns in the database that are of type 'oid', and
25-
removes any entries from the temporary table.
28+
It then scans through all columns in the database that are of type 'oid',
29+
and removes any matching entries from the temporary table.
30+
31+
The remaining entries in the temp table identify orphaned LOs. These are
32+
removed.
33+
2634

27-
Finally, it runs through the first table, and removes from the second table, any
28-
oid's it finds. What is left are the orphans, and these are removed.
35+
Notes
36+
-----
2937

3038
I decided to place this in contrib as it needs further testing, but hopefully,
31-
this (or a variant of it) would make it into the backed as a "vacuum lo" command
32-
in a later release.
39+
this (or a variant of it) would make it into the backend as a "vacuum lo"
40+
command in a later release.
3341

3442
Peter Mount <peter@retep.org.uk>
3543
http://www.retep.org.uk

‎contrib/vacuumlo/vacuumlo.c

+84-51
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/contrib/vacuumlo/vacuumlo.c,v 1.6 2000/10/24 01:38:20 tgl Exp $
11+
* $Header: /cvsroot/pgsql/contrib/vacuumlo/vacuumlo.c,v 1.7 2000/11/21 17:54:21 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -24,13 +24,15 @@
2424
#include "libpq-fe.h"
2525
#include "libpq/libpq-fs.h"
2626

27+
#define atooid(x) ((Oid) strtoul((x), NULL, 10))
28+
2729
#define BUFSIZE 1024
2830

2931
int vacuumlo(char *, int);
3032

3133

3234
/*
33-
* This vacuums a database. It returns 1 on success, -1 on failure.
35+
* This vacuums LOs of one database. It returns 0 on success, -1 on failure.
3436
*/
3537
int
3638
vacuumlo(char *database, int verbose)
@@ -39,40 +41,68 @@ vacuumlo(char *database, int verbose)
3941
PGresult *res,
4042
*res2;
4143
char buf[BUFSIZE];
42-
int matched = 0; /* Number matched per scan */
44+
int matched;
45+
int deleted;
4346
int i;
4447

4548
conn = PQsetdb(NULL, NULL, NULL, NULL, database);
4649

4750
/* check to see that the backend connection was successfully made */
4851
if (PQstatus(conn) == CONNECTION_BAD)
4952
{
50-
fprintf(stderr, "Connection to database '%s' failed.\n", database);
53+
fprintf(stderr, "Connection to database '%s' failed:\n", database);
5154
fprintf(stderr, "%s", PQerrorMessage(conn));
55+
PQfinish(conn);
5256
return -1;
5357
}
5458

5559
if (verbose)
5660
fprintf(stdout, "Connected to %s\n", database);
5761

5862
/*
59-
* First we create and populate the lo temp table
63+
* First we create and populate the LO temp table
6064
*/
6165
buf[0] = '\0';
6266
strcat(buf, "SELECT DISTINCT loid AS lo ");
6367
strcat(buf, "INTO TEMP TABLE vacuum_l ");
6468
strcat(buf, "FROM pg_largeobject ");
65-
if (!(res = PQexec(conn, buf)))
69+
res = PQexec(conn, buf);
70+
if (PQresultStatus(res) != PGRES_COMMAND_OK)
71+
{
72+
fprintf(stderr, "Failed to create temp table:\n");
73+
fprintf(stderr, "%s", PQerrorMessage(conn));
74+
PQclear(res);
75+
PQfinish(conn);
76+
return -1;
77+
}
78+
PQclear(res);
79+
/*
80+
* Vacuum the temp table so that planner will generate decent plans
81+
* for the DELETEs below.
82+
*/
83+
buf[0] = '\0';
84+
strcat(buf, "VACUUM ANALYZE vacuum_l ");
85+
res = PQexec(conn, buf);
86+
if (PQresultStatus(res) != PGRES_COMMAND_OK)
6687
{
67-
fprintf(stderr, "Failed to create temp table.\n");
88+
fprintf(stderr, "Failed to vacuum temp table:\n");
89+
fprintf(stderr, "%s", PQerrorMessage(conn));
90+
PQclear(res);
6891
PQfinish(conn);
6992
return -1;
7093
}
7194
PQclear(res);
7295

7396
/*
74-
* Now find any candidate tables who have columns of type oid (the
75-
* column oid is ignored, as it has attnum < 1)
97+
* Now find any candidate tables who have columns of type oid.
98+
*
99+
* NOTE: the temp table formed above is ignored, because its real
100+
* table name will be pg_something. Also, pg_largeobject will be
101+
* ignored. If either of these were scanned, obviously we'd end up
102+
* with nothing to delete...
103+
*
104+
* NOTE: the system oid column is ignored, as it has attnum < 1.
105+
* This shouldn't matter for correctness, but it saves time.
76106
*/
77107
buf[0] = '\0';
78108
strcat(buf, "SELECT c.relname, a.attname ");
@@ -81,13 +111,18 @@ vacuumlo(char *database, int verbose)
81111
strcat(buf, " AND a.attrelid = c.oid ");
82112
strcat(buf, " AND a.atttypid = t.oid ");
83113
strcat(buf, " AND t.typname = 'oid' ");
114+
strcat(buf, " AND c.relkind = 'r'");
84115
strcat(buf, " AND c.relname NOT LIKE 'pg_%'");
85-
if (!(res = PQexec(conn, buf)))
116+
res = PQexec(conn, buf);
117+
if (PQresultStatus(res) != PGRES_TUPLES_OK)
86118
{
87-
fprintf(stderr, "Failed to create temp table.\n");
119+
fprintf(stderr, "Failed to find OID columns:\n");
120+
fprintf(stderr, "%s", PQerrorMessage(conn));
121+
PQclear(res);
88122
PQfinish(conn);
89123
return -1;
90124
}
125+
91126
for (i = 0; i < PQntuples(res); i++)
92127
{
93128
char *table,
@@ -97,50 +132,36 @@ vacuumlo(char *database, int verbose)
97132
field = PQgetvalue(res, i, 1);
98133

99134
if (verbose)
100-
{
101-
fprintf(stdout, "Checking %s in %s: ", field, table);
102-
fflush(stdout);
103-
}
104-
105-
res2 = PQexec(conn, "begin");
106-
PQclear(res2);
107-
108-
buf[0] = '\0';
109-
strcat(buf, "DELETE FROM vacuum_l ");
110-
strcat(buf, "WHERE lo IN (");
111-
strcat(buf, "SELECT ");
112-
strcat(buf, field);
113-
strcat(buf, " FROM ");
114-
strcat(buf, table);
115-
strcat(buf, ");");
116-
if (!(res2 = PQexec(conn, buf)))
117-
{
118-
fprintf(stderr, "Failed to check %s in table %s\n", field, table);
119-
PQclear(res);
120-
PQfinish(conn);
121-
return -1;
122-
}
135+
fprintf(stdout, "Checking %s in %s\n", field, table);
136+
137+
/*
138+
* We use a DELETE with implicit join for efficiency. This
139+
* is a Postgres-ism and not portable to other DBMSs, but
140+
* then this whole program is a Postgres-ism.
141+
*/
142+
sprintf(buf, "DELETE FROM vacuum_l WHERE lo = \"%s\".\"%s\" ",
143+
table, field);
144+
res2 = PQexec(conn, buf);
123145
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
124146
{
125-
fprintf(stderr,
126-
"Failed to check %s in table %s\n%s\n",
127-
field, table,
128-
PQerrorMessage(conn)
129-
);
147+
fprintf(stderr, "Failed to check %s in table %s:\n",
148+
field, table);
149+
fprintf(stderr, "%s", PQerrorMessage(conn));
130150
PQclear(res2);
131151
PQclear(res);
132152
PQfinish(conn);
133153
return -1;
134154
}
135155
PQclear(res2);
136-
137-
res2 = PQexec(conn, "end");
138-
PQclear(res2);
139-
140156
}
141157
PQclear(res);
142158

143-
/* Start the transaction */
159+
/*
160+
* Run the actual deletes in a single transaction. Note that this
161+
* would be a bad idea in pre-7.1 Postgres releases (since rolling
162+
* back a table delete used to cause problems), but it should
163+
* be safe now.
164+
*/
144165
res = PQexec(conn, "begin");
145166
PQclear(res);
146167

@@ -150,25 +171,35 @@ vacuumlo(char *database, int verbose)
150171
buf[0] = '\0';
151172
strcat(buf, "SELECT lo ");
152173
strcat(buf, "FROM vacuum_l");
153-
if (!(res = PQexec(conn, buf)))
174+
res = PQexec(conn, buf);
175+
if (PQresultStatus(res) != PGRES_TUPLES_OK)
154176
{
155-
fprintf(stderr, "Failed to read temp table.\n");
177+
fprintf(stderr, "Failed to read temp table:\n");
178+
fprintf(stderr, "%s", PQerrorMessage(conn));
179+
PQclear(res);
156180
PQfinish(conn);
157181
return -1;
158182
}
183+
159184
matched = PQntuples(res);
185+
deleted = 0;
160186
for (i = 0; i < matched; i++)
161187
{
162-
Oid lo = (Oid) atoi(PQgetvalue(res, i, 0));
188+
Oid lo = atooid(PQgetvalue(res, i, 0));
163189

164190
if (verbose)
165191
{
166-
fprintf(stdout, "\rRemoving lo %6d \n", lo);
192+
fprintf(stdout, "\rRemoving lo %6u ", lo);
167193
fflush(stdout);
168194
}
169195

170196
if (lo_unlink(conn, lo) < 0)
171-
fprintf(stderr, "Failed to remove lo %d\n", lo);
197+
{
198+
fprintf(stderr, "\nFailed to remove lo %u: ", lo);
199+
fprintf(stderr, "%s", PQerrorMessage(conn));
200+
}
201+
else
202+
deleted++;
172203
}
173204
PQclear(res);
174205

@@ -177,10 +208,12 @@ vacuumlo(char *database, int verbose)
177208
*/
178209
res = PQexec(conn, "end");
179210
PQclear(res);
211+
180212
PQfinish(conn);
181213

182214
if (verbose)
183-
fprintf(stdout, "\rRemoved %d large objects from %s.\n", matched, database);
215+
fprintf(stdout, "\rRemoved %d large objects from %s.\n",
216+
deleted, database);
184217

185218
return 0;
186219
}
@@ -204,7 +237,7 @@ main(int argc, char **argv)
204237
if (strcmp("-v", argv[arg]) == 0)
205238
verbose = !verbose;
206239
else
207-
rc += vacuumlo(argv[arg], verbose);
240+
rc += (vacuumlo(argv[arg], verbose) != 0);
208241
}
209242

210243
return rc;

0 commit comments

Comments
 (0)