| Bug #80523 | current_memory in sys.session can go negative! | ||
|---|---|---|---|
| Submitted: | 26 Feb 2016 9:23 | Modified: | 26 Feb 2016 10:50 |
| Reporter: | Shane Bester (Platinum Quality Contributor) | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: Performance Schema | Severity: | S3 (Non-critical) |
| Version: | 8.0.0, 8.0.11 | OS: | Windows |
| Assigned to: | Marc ALFF | CPU Architecture: | Any |
[26 Feb 2016 10:50]
MySQL Verification Team
found the culprit in my tests.
-------------------------------
With memory instrumentation enabled....
mysql> select * from sys.session where current_memory\G
*************************** 1. row ***************************
thd_id: 28
conn_id: 4
user: NULL
db: test
command: Query
state: Sending data
time: 0
current_statement: select * from sys.session where current_memory
statement_latency: 2.19 ms
progress: NULL
lock_latency: 1.50 ms
rows_examined: 0
rows_sent: 0
rows_affected: 0
tmp_tables: 4
tmp_disk_tables: 1
full_scan: YES
last_statement: NULL
last_statement_latency: NULL
current_memory: 3.02 MiB
last_wait: NULL
last_wait_latency: NULL
source: NULL
trx_latency: NULL
trx_state: NULL
trx_autocommit: NULL
pid: 9640
program_name: mysql
1 row in set (0.06 sec)
mysql> set global key_buffer_size = 1024 * 64;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from sys.session where current_memory\G
*************************** 1. row ***************************
thd_id: 28
conn_id: 4
user: NULL
db: test
command: Query
state: Sending data
time: 0
current_statement: select * from sys.session where current_memory
statement_latency: 2.14 ms
progress: NULL
lock_latency: 1.50 ms
rows_examined: 0
rows_sent: 0
rows_affected: 0
tmp_tables: 4
tmp_disk_tables: 1
full_scan: YES
last_statement: NULL
last_statement_latency: NULL
current_memory: -5161446 bytes
last_wait: NULL
last_wait_latency: NULL
source: NULL
trx_latency: NULL
trx_state: NULL
trx_autocommit: NULL
pid: 9640
program_name: mysql
1 row in set (0.06 sec)
[4 Mar 2016 8:42]
MySQL Verification Team
complete outputs
Attachment: bug80523_output.txt (text/plain), 1.25 MiB.
[18 Jun 2016 21:36]
Omer Barnir
Posted by developer: Reported version value updated to reflect release name change from 5.8 to 8.0
[25 Jun 2018 5:01]
MySQL Verification Team
Bug #91396 marked as duplicate of this one. Also, updating the recent version reported "8.0.11".
[29 Jun 2018 14:19]
Peter Zaitsev
I also would update it does not seems to be OS specific I observed it on Linux
[30 Dec 2020 4:05]
YAWEN CHENG
current_memory is negative
Attachment: session-20201230.log (application/octet-stream, text), 279.62 KiB.
Description: Seen today on 5.8 mysql> select * from sys.session where current_memory < 1\G *************************** 1. row *************************** thd_id: 30 conn_id: 6 user: NULL db: test command: Query state: starting time: 0 current_statement: commit statement_latency: 292.68 ms progress: NULL lock_latency: 0 ps rows_examined: 0 rows_sent: 0 rows_affected: 0 tmp_tables: 0 tmp_disk_tables: 0 full_scan: NO last_statement: NULL last_statement_latency: NULL current_memory: -17544668 bytes <---------- last_wait: NULL last_wait_latency: NULL source: NULL trx_latency: NULL trx_state: NULL trx_autocommit: NULL pid: 5688 program_name: NULL 1 row in set (0.11 sec) How to repeat: no exact testcase yet.