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| 1 | +# Minimal test testing synchronous replication sync_state transition |
| 2 | +use strict; |
| 3 | +use warnings; |
| 4 | +use PostgresNode; |
| 5 | +use TestLib; |
| 6 | +use Test::Moretests=> 8; |
| 7 | + |
| 8 | +# Query checking sync_priority and sync_state of each standby |
| 9 | +my$check_sql ="SELECT application_name, sync_priority, sync_state FROM pg_stat_replication ORDER BY application_name;"; |
| 10 | + |
| 11 | +# Check that sync_state of each standby is expected. |
| 12 | +# If $setting is given, synchronous_standby_names is set to it and |
| 13 | +# the configuration file is reloaded before the test. |
| 14 | +subtest_sync_state |
| 15 | +{ |
| 16 | +my ($self,$expected,$msg,$setting) =@_; |
| 17 | + |
| 18 | +if (defined($setting)) |
| 19 | +{ |
| 20 | +$self->psql('postgres', |
| 21 | +"ALTER SYSTEM SET synchronous_standby_names = '$setting';"); |
| 22 | +$self->reload; |
| 23 | +} |
| 24 | + |
| 25 | +my$result =$self->safe_psql('postgres',$check_sql); |
| 26 | +is($result,$expected,$msg); |
| 27 | +} |
| 28 | + |
| 29 | +# Initialize master node |
| 30 | +my$node_master = get_new_node('master'); |
| 31 | +$node_master->init(allows_streaming=> 1); |
| 32 | +$node_master->start; |
| 33 | +my$backup_name ='master_backup'; |
| 34 | + |
| 35 | +# Take backup |
| 36 | +$node_master->backup($backup_name); |
| 37 | + |
| 38 | +# Create standby1 linking to master |
| 39 | +my$node_standby_1 = get_new_node('standby1'); |
| 40 | +$node_standby_1->init_from_backup($node_master,$backup_name, |
| 41 | +has_streaming=> 1); |
| 42 | +$node_standby_1->start; |
| 43 | + |
| 44 | +# Create standby2 linking to master |
| 45 | +my$node_standby_2 = get_new_node('standby2'); |
| 46 | +$node_standby_2->init_from_backup($node_master,$backup_name, |
| 47 | +has_streaming=> 1); |
| 48 | +$node_standby_2->start; |
| 49 | + |
| 50 | +# Create standby3 linking to master |
| 51 | +my$node_standby_3 = get_new_node('standby3'); |
| 52 | +$node_standby_3->init_from_backup($node_master,$backup_name, |
| 53 | +has_streaming=> 1); |
| 54 | +$node_standby_3->start; |
| 55 | + |
| 56 | +# Check that sync_state is determined correctly when |
| 57 | +# synchronous_standby_names is specified in old syntax. |
| 58 | +test_sync_state($node_master,qq(standby1|1|sync |
| 59 | +standby2|2|potential |
| 60 | +standby3|0|async), |
| 61 | +'old syntax of synchronous_standby_names', |
| 62 | +'standby1,standby2'); |
| 63 | + |
| 64 | +# Check that all the standbys are considered as either sync or |
| 65 | +# potential when * is specified in synchronous_standby_names. |
| 66 | +# Note that standby1 is chosen as sync standby because |
| 67 | +# it's stored in the head of WalSnd array which manages |
| 68 | +# all the standbys though they have the same priority. |
| 69 | +test_sync_state($node_master,qq(standby1|1|sync |
| 70 | +standby2|1|potential |
| 71 | +standby3|1|potential), |
| 72 | +'asterisk in synchronous_standby_names', |
| 73 | +'*'); |
| 74 | + |
| 75 | +# Stop and start standbys to rearrange the order of standbys |
| 76 | +# in WalSnd array. Now, if standbys have the same priority, |
| 77 | +# standby2 is selected preferentially and standby3 is next. |
| 78 | +$node_standby_1->stop; |
| 79 | +$node_standby_2->stop; |
| 80 | +$node_standby_3->stop; |
| 81 | + |
| 82 | +$node_standby_2->start; |
| 83 | +$node_standby_3->start; |
| 84 | + |
| 85 | +# Specify 2 as the number of sync standbys. |
| 86 | +# Check that two standbys are in 'sync' state. |
| 87 | +test_sync_state($node_master,qq(standby2|2|sync |
| 88 | +standby3|3|sync), |
| 89 | +'2 synchronous standbys', |
| 90 | +'2(standby1,standby2,standby3)'); |
| 91 | + |
| 92 | +# Start standby1 |
| 93 | +$node_standby_1->start; |
| 94 | + |
| 95 | +# Create standby4 linking to master |
| 96 | +my$node_standby_4 = get_new_node('standby4'); |
| 97 | +$node_standby_4->init_from_backup($node_master,$backup_name, |
| 98 | +has_streaming=> 1); |
| 99 | +$node_standby_4->start; |
| 100 | + |
| 101 | +# Check that standby1 and standby2 whose names appear earlier in |
| 102 | +# synchronous_standby_names are considered as sync. Also check that |
| 103 | +# standby3 appearing later represents potential, and standby4 is |
| 104 | +# in 'async' state because it's not in the list. |
| 105 | +test_sync_state($node_master,qq(standby1|1|sync |
| 106 | +standby2|2|sync |
| 107 | +standby3|3|potential |
| 108 | +standby4|0|async), |
| 109 | +'2 sync, 1 potential and 1 async'); |
| 110 | + |
| 111 | +# Check that sync_state of each standby is determined correctly |
| 112 | +# when num_sync exceeds the number of names of potential sync standbys |
| 113 | +# specified in synchronous_standby_names. |
| 114 | +test_sync_state($node_master,qq(standby1|0|async |
| 115 | +standby2|4|sync |
| 116 | +standby3|3|sync |
| 117 | +standby4|1|sync), |
| 118 | +'num_sync exceeds the num of potential sync standbys', |
| 119 | +'6(standby4,standby0,standby3,standby2)'); |
| 120 | + |
| 121 | +# The setting that * comes before another standby name is acceptable |
| 122 | +# but does not make sense in most cases. Check that sync_state is |
| 123 | +# chosen properly even in case of that setting. |
| 124 | +# The priority of standby2 should be 2 because it matches * first. |
| 125 | +test_sync_state($node_master,qq(standby1|1|sync |
| 126 | +standby2|2|sync |
| 127 | +standby3|2|potential |
| 128 | +standby4|2|potential), |
| 129 | +'asterisk comes before another standby name', |
| 130 | +'2(standby1,*,standby2)'); |
| 131 | + |
| 132 | +# Check that the setting of '2(*)' chooses standby2 and standby3 that are stored |
| 133 | +# earlier in WalSnd array as sync standbys. |
| 134 | +test_sync_state($node_master,qq(standby1|1|potential |
| 135 | +standby2|1|sync |
| 136 | +standby3|1|sync |
| 137 | +standby4|1|potential), |
| 138 | +'multiple standbys having the same priority are chosen as sync', |
| 139 | +'2(*)'); |
| 140 | + |
| 141 | +# Stop Standby3 which is considered in 'sync' state. |
| 142 | +$node_standby_3->stop; |
| 143 | + |
| 144 | +# Check that the state of standby1 stored earlier in WalSnd array than |
| 145 | +# standby4 is transited from potential to sync. |
| 146 | +test_sync_state($node_master,qq(standby1|1|sync |
| 147 | +standby2|1|sync |
| 148 | +standby4|1|potential), |
| 149 | +'potential standby found earlier in array is promoted to sync'); |