select count(*) from pg_stat_activity; 2、获取数据库最大连接数 show max_connections 3、查询当前连接数详细信息 select * from pg_stat_activity; 4、查询数据库中各个用户名对应的数据库连接数 select usename, count(*) from pg_stat_activity group by usename; 二、赋权操作 1、为指定用户赋予指定...
1.查下超过10 s的查询语句 select*From pg_stat_activitywherequery_start<=now()- interval'10 sec'and state notin('idle') and pid<>pg_backend_pid() and query ilike'select%'order by query_start ; 2. 超过10s的查询会被干掉 selectpg_terminate_backend(pid) From pg_stat_activitywherequery_st...
From pg_stat_activity where query_start<=now()- interval'10 sec' and state not in ('idle') and pid<>pg_backend_pid() and query ilike 'select%' order by query_start ; 1. 2. 3. 4. 5. 6. 2. 超过10s的查询会被干掉 select pg_terminate_backend(pid) From pg_stat_activity where ...
With newer pgs it's rather wide (22 columns as I write this). And, it's not always obvious what all this means. So let's try to figure it out. Connected to databasedepeszwith usertestand got: $SELECT*FROMpg_stat_activity ; datid │ datname │ pid │ leader_pid │ usesysid │...
gs_guc reload -N all -I all -c "track_stmt_stat_level='OFF,L0'" gs_guc reload -N all -I all -c "instr_unique_sql_count=2000" 3、慢SQL查询 以下是查用的慢SQL查询语句 select * from dbe_perf.get_global_slow_sql_by_timestamp('2024-01-17 00:00:00', '2024-04-17 23:00:00...
与count(distinct)都是很常见的操作。...count(distinct colA)就是将colA中所有出现过的不同值取出来,相信只要接触过数据库的同学都能明白什么意思。...count(distinct colA)的操作也可以用group by的方式完成,具体代码如下: select count(dist...
SQL best practices – don’t compare count(*) with 0 Every now and then I see something like this: SELECTu.*FROMusers uWHERE0=(SELECTCOUNT(*)FROMaddresses aWHEREa.user_id=u.id); and it kinda pains me. So figured, I'll write about what is the problem with it, and how to avoid...
static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result, int result_len, int *bflags) { unsigned char scsi_cmd[MAX_COMMAND_SIZE]; int first_inquiry_len, try_inquiry_len, next_inquiry_len; int response_len = 0; int pass, count, result; struct scsi_sense_hdr ...
CustVendSumForPaym::countPaymFormats Method [AX 2012] CustVendSumForPaym::countPaymModes Method [AX 2012] CustVendSumForPaym::description Method [AX 2012] CustVendSumForPaym::main Method [AX 2012] CustVendSumForPaym::newLedgerJournalTrans Method [AX 2012] CustVendSumForPaymRemittance Class [...
在数据库的日常使用中,难免会遇到慢 SQL,遇到慢 SQL 本身并不可怕,困难之处在于如何识别慢 SQL 并对其优化,使它不至于拖慢整个系统的性能,避免危害到日常业务的正常进行。 上期我们讲了索引原因、系统配置和资源竞争导致的慢 SQL,今天我们继续分析和总结。