Questions tagged [cache]
A cache is a mechanism for temporarily storing (caching) data in memory in order to reduce access time to data stored on disk drives.
178 questions
0 votes
0 answers
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Do redisson locks, which are distributed, work as single JVM locks as well
I am using RLockReactive from redisson to get the redis distributed lock, then performing a Supplier operation. The Supplier runs 2 steps in sequence, but I am seeing that while the lock is kept ...
0 votes
1 answer
103 views
Is pg_basebackup Performance Limited by Files Page Cache?
I have PostgreSQL 15 running in a Kubernetes Pod using the Zalando Spilo image, managed by Patroni. The container has a memory limit of 16 GB, and the database size is 40 GB (data dir on disk). When I ...
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2 votes
1 answer
85 views
Oracle 19 Result_cache
How can I tell if my database has RESULT_CACHE setup? I am not a dba, but am trying to utilize this feature in my functions. Added RESULT_CACHE compiles OK, but when I put debugging statements in my ...
zakariah1
-1 votes
1 answer
234 views
Why is PostgreSQL reading from heap and how to improve cache usage?
I have an SQL query that executes slowly on PostgreSQL 13.15 with 128GB of memory. The query mainly performs a Bitmap Heap Scan, and I’ve noticed that many reads are coming from the heap instead of ...
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0 votes
1 answer
93 views
PostgreSQL: Is there any way to differentiate an actual Disk I/O from system cache hit?
When using EXPLAIN with buffers, the blocks read sometimes are actually from system cache, this is understandable sometimes based on the read time. But is there any proper way to understand a system ...
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0 votes
1 answer
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Does MySQL invalidate or amend a cached table when rows are added, updated or deleted?
What does MySQL (InnoDB) do when it has cached an entire table into memory and one or more rows in that table changes? Does MySQL in this instance amend the cache in memory, or would it consider the ...
0 votes
1 answer
155 views
MongoDB: What cause bytesRead in insert operation?
Recently we had high CPU/Memory and I/O usage on our MongoDB. While checking the logs all I found is some insert during this period. While inspecting logs I noticed most of the insert logs have ...
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2 votes
4 answers
117 views
Buffer Pool caching in Sql clarification
I might sound a little naive to ask this question but I couldn’t find out the answer anywhere. So my understanding is that the buffer in a sql db maintains disk pages in cache so that when a query ...
2 votes
1 answer
1k views
How to know how much memory is used by each DB user in the cache buffer?
Using this query: SELECT A.CACHE_BUFFER_TOTAL, B.CACHE_BUFFER_USED, A.CACHE_BUFFER_TOTAL - B.CACHE_BUFFER_USED AS CACHE_BUFFER_FREE FROM (SELECT BYTES / 1024 / 1024 ...
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1 vote
1 answer
3k views
Why the second query is so much faster than the first one?
I have a query that look like this: SELECT DISTINCT "articles"."id", "articles"."company_uuid", "articles"."status", "articles&...
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1 vote
1 answer
124 views
Which SQL Server component is in charge with checking cached execution plans for a given query?
I understand that whenever SQL server receives a query it looks in the cache plan for any matching execution plans for that query. However, most of the resources that I encountered don't specify ...
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0 votes
0 answers
207 views
Disk based Key-Value store to use as LRU cache?
I am looking for a key value store to use as a LRU cache for my application. It needs to hold a lot of data (100G - 1000G) which is why I say disk based. Things I have found via Google seem to be ...
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0 votes
2 answers
84 views
Performance for query filtered by user preference
I have an app, that shows data based on user preference. I will simplify it in this theoretical example: The app shows articles filtered based on user preference for their favorite authors or their ...
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0 votes
1 answer
255 views
Oracle 19c create table result_cache clause syntax
I could not find the exact syntax for the "Result_Cache" clause in the Oracle 19c documentation for the CREATE TABLE statement. It mentions the values of DEFAULT or FORCE, but not the ...
- 1,170
0 votes
1 answer
239 views
Testing strategies when tuning a stored procedure
I'm tuning a stored procedure that is used by the first page that loads whenever a user logs into our website and it's very frequently used. When I run the procedure the first time it runs in about 10 ...
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