summaryrefslogtreecommitdiffstats
path: root/syncshadowdb
blob: 4733dbb58f63ace617caacade1361203cf421214 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
#!/usr/bonsaitools/bin/perl -w
# -*- Mode: perl; indent-tabs-mode: nil -*-
#
# The contents of this file are subject to the Mozilla Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/MPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is the Bugzilla Bug Tracking System.
#
# The Initial Developer of the Original Code is Netscape Communications
# Corporation. Portions created by Netscape are
# Copyright (C) 1998 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s): Terry Weissman <terry@mozilla.org>
#                 David Gardiner <david.gardiner@unisa.edu.au>

use diagnostics;
use strict;

require "globals.pl";
require "defparams.pl";

# Shut up misguided -w warnings about "used only once".  "use vars" just
# doesn't work for me.

sub sillyness {
    my $zz;
    open SAVEOUT,">/dev/null";
    $zz = $::db;
    $zz = $::dbwritesallowed;
}

my $verbose = 0;
my $syncall = 0;

sub Usage {
    print "Usage: syncshadowdb [-v] [-syncall]\n";
    exit;
}

foreach my $opt (@ARGV) {
    if ($opt eq '-v') {
        $verbose = 1;
    } elsif ($opt eq '-syncall') {
        $syncall = 1;
        $verbose = 1;
    } elsif ($opt eq '--') {
        # do nothing - null parameter so we can use
        # multi-param system() call in globals.pl
    } else {
        Usage();
    }
}
$| = 1;

my $logtostderr = 0;

sub Verbose ($) {
    my ($str) = (@_);
    if ($verbose) {
        if ($logtostderr) {
            print STDERR $str, "\n";
        } else {
            print $str, "\n";
        }
    }
}

if (!Param("shadowdb")) {
    Verbose("We don't have shadow databases turned on; no syncing performed.");
    exit;
}

my $wasusing = Param("queryagainstshadowdb");

$::param{'queryagainstshadowdb'} = 1; # Force us to be able to use the
                                      # shadowdb, even if other processes
                                      # are not supposed to.


ConnectToDatabase(1);

Verbose("Acquiring lock");
if ( $syncall == 1) {
    SendSQL("SELECT GET_LOCK('synclock', 2700)");
} else {
    SendSQL("SELECT GET_LOCK('synclock', 1)");
}
if (!FetchOneColumn()) {
    Verbose("Couldn't get the lock to do the shadow database syncing.");
    exit;
}

my $shadowtable = "$::db_name.shadowlog";

if (!$syncall) {
    Verbose("Looking for requests to sync the whole database.");
    SendSQL("SELECT id FROM $shadowtable " .
            "WHERE reflected = 0 AND command = 'SYNCUP'");
    if (FetchOneColumn()) {
        $syncall = 1;
    }
}

if ($syncall) {
    Verbose("Syncing up the shadow database by copying entire database in.");
    if ($wasusing) {
        $::param{'queryagainstshadowdb'} = 0;
        WriteParams();
        Verbose("Disabled reading from the shadowdb. Sleeping 10 seconds to let other procs catch up.");
        sleep(10);
        $::param{'queryagainstshadowdb'} = 1;
    }
    my @tables;
    SendSQL("SHOW TABLES");
    my $query = "";
    while (MoreSQLData()) {
        my $table = FetchOneColumn();
        push(@tables, $table);
        if ($query) {
            $query .= ", $table WRITE";
        } else {
            $query = "LOCK TABLES $table WRITE";
        }
    }
    if (@tables) {
        Verbose("Locking entire shadow database");
        SendSQL($query);
        foreach my $table (@tables) {
            Verbose("Dropping old shadow table $table");
            SendSQL("DROP TABLE $table");
        }
        SendSQL("UNLOCK TABLES");
    }    
    # Carefully lock the whole real database for reading, except for the
    # shadowlog table, which we lock for writing.  Then dump everything
    # into the shadowdb database.  Then mark everything in the shadowlog
    # as reflected.  Only then unlock everything.  This sequence causes
    # us to be sure not to miss anything or get something twice.
    SendSQL("USE $::db_name");
    SendSQL("SHOW TABLES");
    @tables = ();
    $query = "LOCK TABLES shadowlog WRITE";
    while (MoreSQLData()) {
        my $table = FetchOneColumn();
        if ($table ne "shadowlog") {
            $query .= ", $table READ";
            push(@tables, $table);
        }
    }
    Verbose("Locking entire database");
    SendSQL($query);
    my $tempfile = "data/tmpsyncshadow.$$";
    Verbose("Dumping database to a temp file ($tempfile).");
    my @ARGS = ("-u", $::db_user);
    if ($::db_pass) { push @ARGS, "-p$::db_pass" }
    push @ARGS, "-l", "-e", $::db_name, @tables;
    open SAVEOUT, ">&STDOUT";     # stash the original output stream
    open STDOUT, ">$tempfile";    # redirect to file
    select STDOUT; $| = 1;        # disable buffering
    system("mysqldump", @ARGS);
    open STDOUT, ">&SAVEOUT";     # redirect back to original stream
    Verbose("Restoring from tempfile into shadowdb");
    my $extra = "-u $::db_user";
    if ($::db_pass) {
        $extra .= " -p$::db_pass";
    }
    if ($verbose) {
        $extra .= " -v";
    }
    open(MYSQL, "cat $tempfile | mysql $extra " .
         Param("shadowdb") . "|") || die "Couldn't do db copy";
    my $count = 0;
    while (<MYSQL>) {
        print ".";
        $count++;
        if ($count % 70 == 0) {
            print "\n";
        }
    }
    close(MYSQL);
    unlink($tempfile);
    Verbose("");
    
    
    $::dbwritesallowed = 1;
#    SendSQL("UPDATE shadowlog SET reflected = 1 WHERE reflected = 0", 1);
    SendSQL("DELETE FROM shadowlog", 1);
    SendSQL("UNLOCK TABLES");
    if ($wasusing) {
        Verbose("Reenabling other processes to read from the shadow db");
        $::param{'queryagainstshadowdb'} = 1;
        WriteParams();
    }
    Verbose("OK, done.");
}

Verbose("Looking for commands to execute.");
$::dbwritesallowed = 1;

# Make us low priority, to not block anyone who is trying to actually use
# the shadowdb.  Note that this is carefully coded to ignore errors; we want
# to keep going even on older mysqld's that don't have the
# SQL_LOW_PRIORITY_UPDATES option.
$::db->do("SET OPTION SQL_LOW_PRIORITY_UPDATES = 1"); 

while (1) {
    SendSQL("SELECT id, command FROM $shadowtable WHERE reflected = 0 " .
            "ORDER BY id LIMIT 1");
    my ($id, $command) = (FetchSQLData());
    if (!$id) {
        last;
    }
    Verbose("Executing command in shadow db: $command");
    SendSQL($command, 1);
    SendSQL("UPDATE $shadowtable SET reflected = 1 WHERE id = $id", 1);
}

Verbose("Releasing lock.");
SendSQL("SELECT RELEASE_LOCK('synclock')");