Questions tagged [query-cache]
58 questions
32
votes
3 answers
Why did MySQL remove the query cache feature after version 8.0?
Why did MySQL remove the query cache feature after version 8.0?
shaoyihe
- 477
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30
votes
3 answers
Why query_cache_type is disabled by default start from MySQL 5.6?
We've upgraded to MySQL 5.6 and start seeing the loading of db server increased significantly, and finally found out the query_cache_type is defaulted to off start from 5.6.
We enabled it again and see the loading decrease, why this value is being…
Yoga
- 549
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11
votes
1 answer
Qcache_free_memory not full yet I get a lot of Qcache_lowmem_prunes
I just started dabbling with the query cache for our CMS.
Can anyone tell me (or at least give a good guess) why I get a lot of Qcache_lowmem_prunes when more than half of Qcache_free_memory is free?
query_cache_size=512M
query_cache_limit=1M
This…
Nifle
- 1,472
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10
votes
4 answers
What is the best alternative for MySQL Query Cache?
The Query Cache has been removed in MySQL 8. Is there any better alternative for Query Cache in MySQL?
Dipin V A
- 109
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9
votes
1 answer
Query profiling shows "Waiting for query cache lock" but query_cache_size is 0
We have a statement based replication server that has been experiencing slowdowns and during the event SHOW FULL PROCESSLIST showed the replication query stuck on "Waiting for query cache lock" which was surprising because the server…
John Donahue
- 93
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8
votes
2 answers
How does MySQL/InnoDB caching work internally when you perform two similar, but not identical, select requests?
I have some confusion about how the Innodb buffer pool works.
Let's say I have table with 15 records, if I execute: select ... between 1 to 10 then that result will cached in buffer(?).
My question is: if i execute select .... between 1 to 15 next…
Sudeep shetty
- 89
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4
votes
2 answers
Is it possible to delete cache in Mongo?
My case is that I run several queries in Mongo and measure the response time. I know that Mongo uses Memory Mapped files and cache some data in RAM.
If I create an index and run a query the execution time is 2,07 seconds. When I run the qeury again…
e7lT2P
- 175
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3
votes
2 answers
Can I tell MySQL what to cache?
Pretty straightforward question:
Let's say I have a specific query that I know is regularly used, can I tell MySQL to always cache it "automatically" ... i.e. once the cached query results are flushed the mysqld immediately runs that query again to…
Kolja
- 363
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3
votes
1 answer
MariaDB not caching any queries
I tested several simple queries like such:
SELECT COUNT(*) FROM Users WHERE courses='a';
But none are being cached. The following are the cache related variables:
show variables like…
Question Overflow
- 1,009
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3
votes
1 answer
query cache hit value is not changing in my database
The query cache hit value is not changing in my database only for some queries.If I write
select * from drugs_info limit 1000;
the query cache hit has changed, but if I execute the following queries for two to three times the query cache hit is…
user28536
- 31
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3
votes
2 answers
AWS RDS Aurora mysql Query Cache
AWS RDS mysql 5.7
Current Query Cache is by default enabled on Aurora mysql. (16GB query cache size, on 300GB of RAM). Am facing some deadlocks from Hangfire and it doesn't show anything to having Query Cache locks.
There are 2 blog posts that seem…
Max
- 133
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3
votes
1 answer
high cached_page_count - when to start to worry and what can I do about it?
Below are my top 10 cached page counts.
We're having query performance issues with the top 2 tables; the queries never change but the run times are very volatile.
I cant seem to work out were the issues are and suspect through a bit of online…
Simon
- 219
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3
votes
1 answer
Cache query that is not stored in QueryCache
One of our customers has an online-shop running xt-commerce 4.2.
This version of the e-commerce-software has a very expensive query for the category-tree. The query adds about 3 seconds delay and is executed on every page request. Since the software…
Martin Seitl
- 161
- 8
2
votes
2 answers
Optimize MySQL query_cache_min_res_unit
My query cache settings are the following:
mysql> SHOW GLOBAL STATUS LIKE 'Q%';
+-------------------------+----------+
| Variable_name | Value |
+-------------------------+----------+
| Qcache_free_blocks | 2270 |
|…
Howard
- 249
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2
votes
2 answers
DBCC FREESYSTEMCACHE(‘SQL Plans’) deletes all ad-hoc and prepared plans, not just single-used ones
Kimberly Tripp's blog post here made me think that running DBCC FREESYSTEMCACHE('SQL Plans') clears just single-used ad-hoc and prepared query plans. But that seems incorrect. It clears all. Which is probaly not a good option to go if you have high…
jericzech
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