agens-graph - 如何在 AgentGraph 上找到锁定等待查询？

Question

我正在遭受 AgensGraph 的缓慢交易。CPU 使用率极低。我猜是锁定等待的情况。

如何找到锁定等待查询？

Answer 1

您可以尝试使用 AgnsGraph 的 lock-wait log。

首先，更改“postgresql.conf”上的参数

log_lock_waits = on
deadlock_timeout = 1s

二、重启AgensGraph。

$ ag_ctl stop
waiting for server to shut down.... done
server stopped
$ ag_ctl start
server starting

最后，运行查询并检查日志文件。

[会话1：块传输]

agens=# begin;
BEGIN
agens=# create (:n{id:1});
GRAPH WRITE (INSERT VERTEX 1, INSERT EDGE 0)
agens=# rollback;
ROLLBACK
agens=# 

[会话2：锁定等待事务]

agens=# create (:n{id:1});
GRAPH WRITE (INSERT VERTEX 1, INSERT EDGE 0)

从日志文件中检查日志。

LOG:  process 3908 still waiting for ShareLock on transaction 1586 after 1001.058 ms
DETAIL:  Process holding the lock: 3906. Wait queue: 3908.
CONTEXT:  while inserting index tuple (0,7) in relation "n_id_idx"
STATEMENT:  create (:n{id:1});
LOG:  process 3908 acquired ShareLock on transaction 1586 after 4639.630 ms
CONTEXT:  while inserting index tuple (0,7) in relation "n_id_idx"
STATEMENT:  create (:n{id:1});