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如果可以的话，我想在添加更多细节之前写一个问题的简短摘要，以使我的问题更清晰：

我有一个 BDR 组在生产中运行，复制在所有节点中都可以正常工作，但是我在其中一个节点中遇到了关于复制槽的错误，我想在不破坏其他任何东西的情况下修复这些错误......

更多细节：

我有一个在 PostgreSQL 9.4 上运行的三节点 BDR 组，2 个节点使用 RedHat7，另一个使用 Centos7。数据库名称是“MCT”。

node_sysid         |node_timeline|node_dboid|node_status|node_name |node_local_dsn |node_init_from_dsn |node_read_only|
-------------------|-------------|----------|-----------|----------|---------------|-------------------|--------------|
6363474972929529353|            4|    263746|r          |REDHAT_1  |172.16.5.180   |                   |false         |
6182181726884158214|            2|    623638|r          |REDHAT_2  |192.168.251.30 | 172.16.5.180      |false         |
6197060214704992943|            2|    224093|r          |CENTOS_1  |172.16.5.184   | 172.16.5.180      |false         |

从任何节点到其他节点的复制都运行良好，但是......

所有节点都在其日志中显示复制槽问题：

REDHAT_1：

2020-11-25 13:26:50.051 CET,"postgres","MCT",6607,"192.168.251.30:60463",5fbe4d8a.19cf,1,"idle",2020-11-25 13:26:50 CET,23/0,0,ERROR,55006,"replication slot ""bdr_263746_6182181726884158214_2_16389__"" is already active for pid 6097",,,,,,,,,"bdr (6182181726884158214,2,16389,):receive"

REDHAT_2：

2020-11-25 13:26:36.153 CET,,,2142,,5fbe48a5.85e,1015,,2020-11-25 13:05:57 CET,,0,LOG,00000,"proceso «background worker»: bdr (6182181726884158214,2,16389,)->bdr (6197060214704992943,2, (PID 12152) terminó con código de salida 1",,,,,,,,,""
2020-11-25 13:26:39.375 CET,,,2142,,5fbe48a5.85e,1016,,2020-11-25 13:05:57 CET,,0,LOG,00000,"iniciando el proceso «background worker» «bdr (6182181726884158214,2,16389,)->bdr (6363474972929529353,4,»",,,,,,,,,""
2020-11-25 13:26:39.389 CET,,,12154,,5fbe4d7f.2f7a,1,,2020-11-25 13:26:39 CET,14/0,0,FATAL,XX000,"could not send replication command ""START_REPLICATION SLOT ""bdr_263746_6182181726884158214_2_16389__"" LOGICAL CE4/BD6AF6A8 (pg_version '90410', pg_catversion '201409291', bdr_version '10002', bdr_variant 'BDR', min_bdr_version '700', sizeof_int '4', sizeof_long '8', sizeof_datum '8', maxalign '8', float4_byval '1', float8_byval '1', integer_datetimes '1', bigendian '0', db_encoding 'UTF8', replication_sets '""default""', db_encoding 'UTF8')"": ERROR:  replication slot ""bdr_263746_6182181726884158214_2_16389__"" is already active for pid 6097, sqlstate: 55006",,,,,,,,,"bdr (6182181726884158214,2,16389,): apply"
2020-11-25 13:26:39.390 CET,,,2142,,5fbe48a5.85e,1017,,2020-11-25 13:05:57 CET,,0,LOG,00000,"proceso «background worker»: bdr (6182181726884158214,2,16389,)->bdr (6363474972929529353,4, (PID 12154) terminó con código de salida 1",,,,,,,,,""
2020-11-25 13:26:41.155 CET,,,2142,,5fbe48a5.85e,1018,,2020-11-25 13:05:57 CET,,0,LOG,00000,"iniciando el proceso «background worker» «bdr (6182181726884158214,2,16389,)->bdr (6197060214704992943,2,»",,,,,,,,,""
2020-11-25 13:26:41.165 CET,,,12155,,5fbe4d81.2f7b,1,,2020-11-25 13:26:41 CET,14/0,0,FATAL,XX000,"could not send replication command ""START_REPLICATION SLOT ""bdr_224093_6182181726884158214_2_16389__"" LOGICAL 9B4/F020E568 (pg_version '90410', pg_catversion '201409291', bdr_version '10002', bdr_variant 'BDR', min_bdr_version '700', sizeof_int '4', sizeof_long '8', sizeof_datum '8', maxalign '8', float4_byval '1', float8_byval '1', integer_datetimes '1', bigendian '0', db_encoding 'UTF8', replication_sets '""default""', db_encoding 'UTF8')"": ERROR:  replication slot ""bdr_224093_6182181726884158214_2_16389__"" is already active for pid 2192

CENTOS_1：

2020-11-25 13:26:56.208 CET,"postgres","MCT",2668,"192.168.251.30:55270",5fbe4d90.a6c,1,"idle",2020-11-25 13:26:56 CET,10/0,0,ERROR,55006,"replication slot ""bdr_224093_6182181726884158214_2_16389__"" is already active for pid 2192",,,,,,,,,"bdr (6182181726884158214,2,16389,):receive"

如果我运行此查询：

select
    pg_catalog.inet_server_addr() as server_addr,
    pg_xlog_location_diff(pg_current_xlog_insert_location(),
    flush_location)::int8 as lag_bytes,
    pid,
    application_name,
    client_addr,
    state
from
    pg_stat_replication;

我得到这个结果：

REDHAT_1：

server_addr |lag_bytes|pid |application_name                           |client_addr   |state    |
------------|---------|----|-------------------------------------------|--------------|---------|
172.16.5.180|    21088|6131|bdr (6197060214704992943,2,224093,):receive|172.16.5.184  |streaming|
172.16.5.180|    14440|6097|bdr (6182181726884158214,2,16389,):receive |192.168.251.30|streaming|
172.16.5.180|     3616|6099|bdr (6182181726884158214,2,623638,):receive|192.168.251.30|streaming|

REDHAT_2：

server_addr |lag_bytes|pid |application_name                           |client_addr   |state    |
------------|---------|----|-------------------------------------------|--------------|---------|
172.16.5.184|        0|2191|bdr (6182181726884158214,2,623638,):receive|192.168.251.30|streaming|
172.16.5.184|        0|2192|bdr (6182181726884158214,2,16389,):receive |192.168.251.30|streaming|
172.16.5.184|        0|2203|bdr (6363474972929529353,4,263746,):receive|172.16.5.180  |streaming|

CENTOS_1：

server_addr   |lag_bytes|pid |application_name                           |client_addr   |state    |
--------------|---------|----|-------------------------------------------|--------------|---------|
192.168.251.30|        0|4298|bdr (6182181726884158214,2,16389,):receive |192.168.251.30|streaming|
192.168.251.30|        0|5123|bdr (6197060214704992943,2,224093,):receive|172.16.5.184  |streaming|
192.168.251.30|        0|4313|bdr (6363474972929529353,4,263746,):receive|172.16.5.180  |streaming|

这个查询：

select
    slot_name,
    plugin,
    slot_type,
    datoid,
    "database",
    active,
    xmin,
    catalog_xmin,
    restart_lsn
from
    pg_catalog.pg_replication_slots;

REDHAT_1：

slot_name                                |plugin|slot_type|datoid|database|active|xmin|catalog_xmin|restart_lsn |
-----------------------------------------|------|---------|------|--------|------|----|------------|------------|
bdr_263746_6182181726884158214_2_16389__ |bdr   |logical  |263746|MCT     |true  |    |2466301995  |CE4/CDA614E8|
bdr_263746_6182181726884158214_2_623638__|bdr   |logical  |263746|MCT     |true  |    |2466301995  |CE4/CDA614E8|
bdr_263746_6197060214704992943_2_224093__|bdr   |logical  |263746|MCT     |true  |    |2466301995  |CE4/CDA614E8|

REDHAT_2：

slot_name                                |plugin|slot_type|datoid|database|active|xmin|catalog_xmin|restart_lsn |
-----------------------------------------|------|---------|------|--------|------|----|------------|------------|
bdr_224093_6182181726884158214_2_16389__ |bdr   |logical  |224093|MCT     |true  |    |1464775472  |9B4/FED0BCA8|
bdr_224093_6182181726884158214_2_623638__|bdr   |logical  |224093|MCT     |true  |    |1464775472  |9B4/FED0BCA8|
bdr_224093_6363474972929529353_4_263746__|bdr   |logical  |224093|MCT     |true  |    |1464775472  |9B4/FED0BCA8|

CENTOS_1：

    slot_name                                |plugin|slot_type|datoid|database|active|xmin|catalog_xmin|restart_lsn |
    -----------------------------------------|------|---------|------|--------|------|----|------------|------------|
    bdr_623638_6363474972929529353_4_263746__|bdr   |logical  |623638|MCT     |true  |    |546376380   |85C/647FE110|
    bdr_623638_6182181726884158214_2_16389__ |bdr   |logical  |623638|MCT     |true  |    |546376380   |85C/647FE110|
    bdr_623638_6197060214704992943_2_224093__|bdr   |logical  |623638|MCT     |true  |    |546376380   |85C/647FE110|

因此，我想知道如何在不破坏当前正在生产的 BDR 中的任何内容的情况下摆脱该错误。

有什么想法吗？

先感谢您！

4

1 回答 1

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根本问题是REDHAT_2节点中名为“OLD”的第二个数据库试图与所有节点中的“MCT”同步，并且正在获取复制槽的所有权，因此真正的“MCT”节点无法真正打开连接。

在“旧”数据库中删除 BDR 并重新启动 PSQL 解决了该问题。谢谢

于 2020-12-03T11:17:27.750 回答