Questions tagged [storage]
For questions about the persistent storage of database data.
300
questions
1
vote
2
answers
195
views
Provisioning SQL Server 2019
I'm provisioning a SQL Server 2019 build and have been allocated a virtual server running Windows Server 2016. It has 4 virtual processors and I have 410Gb of drive space to work with.
My build has to ...
- 13
1
vote
2
answers
715
views
Does large text datatypes reserves storage on disk?
I'm design an DB for an app, in a table there is a column MEDIUMTEXT which according to mysql doc can storage on disk upto 16MB.
So my question is if I'm storing a text of 1Mb in this column, will it ...
- 121
0
votes
2
answers
54
views
SQL Server sharing drive location
DBA newbie here. Did some searching online but cannot find a definite answer on this.
Is it acceptable to share the drive where .MDF files reside with other non-SQL Server files such as applications ...
1
vote
0
answers
89
views
MySQL - storing 162 million rows in 1 table as the result of an IFNULL query
I'm working on a legacy web application which uses a MySQL (5.5.65-MariaDB) database which is hosted on a server running CentOS Linux 7.7.1908.
The application is a database of chemical substances and ...
- 111
0
votes
0
answers
155
views
Storing data for machine learning in MySQL
I am currently in the process of developing a machine learning application, where my users can upload their own data to train models. Furthermore, the users must be able to extend their uploaded data ...
- 53
0
votes
0
answers
148
views
MYSQL storage increasing unexpectedly (RDS)
I am total newbie to database game.
& I am using mysql 8.0 RDS 20GB free tier.
I don't have much data on it.(just 300 Mb)
But I always get a mail that you have exceeded 85% of storage limit.(...
- 1
1
vote
2
answers
247
views
MySQL 8.0 table with JSON column that uses JSON "merge" operations has 500k rows but analyze table shows 7MM
I have a database table that according to TABLE STATUS has 7MM rows, but when I SELECT COUNT(*) it only has 500k rows.
This is a problem because table growth is increasing and we're running low on ...
- 11
5
votes
1
answer
188
views
What would cause a table with 80,000 records to use 145GB of space?
I have a table that gets inserted and deleted from every day. On average the record count is 80,000. Roughly 20 fields, 10 of which are VARCHAR(4000) however most of the records have those fields ...
- 61
1
vote
2
answers
435
views
What is the difference between PAGEIOLATCH_* and IO_COMPLETION?
according to this blog:
SQL Server Books online defines IO_COMPLETION as “Occurs while waiting for I/O operations to complete. This wait type generally represents non-data page I/Os. Data page I/O ...
- 1,213
2
votes
1
answer
262
views
SQLite Internals - Records
Hey I'm trying to wrap my head around SQLite data storage, specifically how it is storing Records. I've found a book The Definitive guide to SQLlite, where the author explains internal record format (...
- 121
2
votes
1
answer
494
views
Is it possible to Increase storage performance in azure vm using disk striping?
Given the following Azure VM:
E8s_v3 (8 cpu, 64 GB RAM, 12800 IOPS, 192 MBps)
I added 2 SSD Premium drives, one for data (1024 GBs / 200 MBps / Host Caching enabled read-only) and one for Logs (256 ...
- 363
0
votes
1
answer
1k
views
How does MySQL store the row data internally?
Does a RDBMS store the row data one after another in a data block? Once data block is full, is the new block assigned continuous?
Per my understanding when table is created, DBMS vendor must be ...
- 389
1
vote
0
answers
40
views
How to calcuate current IOPS consumed in AWS
We have a SQL Server hosted on AWS using EC2 and EBS. SQL Files are hosted on EBS. EBS vol type is GP2 and drive IOPS is 480.
At an instance of time Write Througput in AWS is showing is 725 and Read ...
0
votes
1
answer
262
views
Why VolumeQueueLength goes high for SQL Server in AWS
We have one SQL Server hosted on AWS EC2 machine. In the monitoring tab of one of the volume, we are seeing that VolumeQueueLength is periodically reaching to around 32 and then coming back.
So ...
1
vote
0
answers
257
views
MySQL Large History list length & Storage Space
Currently, my MariaDB database server is running out of space, hence I am trying to delete old records (using multiple threads with DELETE FROM tbl WHERE index > ? and index < ?).
My ...
1
vote
1
answer
169
views
Cannot take backup into NAS storage at specific time
I have a job which runs every 30 minute and takes t-log backup of the database suing Ola's script. Every Thursday and Friday at 22:45 I get an error:
11/07/2019 22:45:00,Backup,Unknown,Error: 3041<...
- 1,213
0
votes
0
answers
345
views
Which MySQL settings are the closest equivalent to RDS' "Queue depth"?
I'm trying to find out which MySQL status variables can be used to get as close as possible to the RDS value of "Queue depth".
On a test system, I reckon that %pending% variables may be at least a ...
- 327
0
votes
1
answer
63
views
MySQL datafiles on SMB3 network storage
We have MySQL-server on Ubuntu with InnoDB-datafiles on a local disk. As part of an upgrade program, the company is planning to put the datafiles on a Windows fileserver where they can be mounted with ...
- 101
0
votes
1
answer
202
views
How to grant xp_delete_file to non-sysadmin login?
I want to delete old backups from shared folder, which are located on separate NAS storage, using newly created SQL login. Is there any workaround to execute xp_delete_file using another account which ...
- 1,213
1
vote
1
answer
95
views
Physical co-clustering of two or more logical relations/tables in modern RDBMS
One possible approach to optimize search queries is (a) to store the records that retain data that corresponds to different relations/tables in (b) the same file → on the same pages. That way, a join ...
- 243
2
votes
2
answers
227
views
SQL Server on Windows Server (VMware) - online storage swap
I have a VM cluster designed to store multiple SQL Server instances. We use variety of storage providers (i.e. 3PAR, XIV) which have to be changed now (not relevant to what brand). On Oracle on Linux ...
- 503
0
votes
0
answers
132
views
Partition Alignment in AWS SSD EBS
I'm setting up a new SQL Server 2008 r2 in AWS with IO1 SSD EBS volumes. My smaller EBS volumes are aligned correctly when they were formatted but the larger volumes, 3TB, are not because they used ...
- 1,751
-1
votes
2
answers
860
views
EAV in postgresql
I'm building an application that needs to be deployed several times, with a relatively well organized data model. A table needs to be configured for each deployment with a small number of additional ...
- 1
16
votes
5
answers
2k
views
Attempts to reclaim unused space causes the used space to increase significantly in SQL Server
I have a table in a production database that has a size of 525 GB, of which 383 GB is unused:
I'd like to reclaim some of this space, but, before messing with the production DB, I'm testing some ...
- 193
0
votes
3
answers
691
views
Replace column by LEFT OUTER join to save space
I have a table t1 with 100M row. For column A, 95% of the rows have value NULL0, the other records have values from 1 to 9.
To shrink my table, I'm thinking about moving column A to table t2. t2 ...
- 59
22
votes
4
answers
27k
views
SQL Server has encountered occurences of I/O requests taking longer than 15 seconds
On Production SQL Server, we have following config:
3 Dell PowerEdge R630 servers, combined into Availability Group
All 3 are connected to a single Dell SAN storage unit which is a RAID array
From ...
- 5,144
0
votes
1
answer
258
views
Backup Compression SQL Server vs PURE
We are having a SQL 2016 Standard Edition Server holding 4TB of data. And the compressed backup using maintenance plans is taking around 1.5 hrs. Our storage team claims that as PURE FlashArray is ...
- 372
0
votes
1
answer
58
views
Is it better to install a very large Postgres database (billions of rows) in a real or a virtual machine? [closed]
From my common sense, my physical machine hosting a very large Postgres database (for big data) should be real rather than virtual or container.
Some people say it is better to install on a virtual ...
- 219
2
votes
1
answer
99
views
Understanding the differences in the storage space used by two tables
I have two tables in which, more or less, one contains a subset of data of the other one. There is some data I delete from the first table, which is inserted in the second one as historical data.
...
- 123
2
votes
0
answers
601
views
Postgres configuration for high-latency storage
I'm trying to setup a postgres server using Ceph as storage. After taking benchmarks, it was obvious that even though the storage has a really good throughput, the higher latency brought by network ...
1
vote
2
answers
433
views
Which Oracle datafiles grow in size?
I have downloaded and started up Oracle's pre-built OTN Developer Day VM. The VM is running on an SSD. I want to move datafiles that can grow to a separate mount point (setup as a vmdk on a HDD. more ...
- 131
2
votes
2
answers
101
views
How to point tablespace in Oracle's pre-built Developer Day VM to another mount point
I have downloaded and started up Oracle's pre-built OTN Developer Day VM. The VM is running on an SSD. I want to load some data for development purposes. I am planning to create a new user and load ...
- 131
6
votes
2
answers
3k
views
Slow checkpoint and 15 second I/O warnings on flash storage
Last couple of weeks we've been working on getting to the root cause of what could likely be the cause of the occurrence of these I/O issues and slowdown of the checkpoints.
At first glance it looks ...
- 507
0
votes
1
answer
2k
views
SQL Server Logical IO Block Sizes and Physical Reads
I am trying to understand cache churn caused by SQL statements that are doing some table scans.
Assuming LRU caches, if something is doing 400K logical IOs, how much memory is streamed across (IO ...
- 193
2
votes
1
answer
3k
views
Should TempDB SSD Drive be formatted with 64 Kb Allocation Unit Size?
We have installed dedicated SSD drives for TempDB
First question - should these drives be formatted with 64 Kb allocation size ? Currently it shows 4 Kb (Bytes per Cluster = 4096)
Does TempDB ...
- 5,144
0
votes
2
answers
2k
views
How does MySQL store data, can I detach a mysql Database?
I have used SQL Server in the past which each database is kept in separate files (a data file and a log file) but things are different in MySQL as it seems. The file sizes of these files translates to ...
- 773
2
votes
1
answer
669
views
Calculating total "on row" bytes for each row ... the easy way
We want to calculate the total "on row" storage bytes for each row in the table. As we understand it, we must add up the DATALENGTH() of each column while also accounting for NULLs and things like ...
- 399
4
votes
1
answer
2k
views
RDS MySQL read replica larger than master
We have a Multi AZ AWS MySQL 5.6.40 server with a matching single AZ read replica. Both have 200GB of storage available. However, the read replica is rapidly running out of free storage space, while ...
- 51
0
votes
0
answers
60
views
fix oracle 11.2 asm performances (bad disks repartition)
i've a single Oracle 11.2 node with really bad performances and i figure out that there's a lun always running at 100% IO.
This is the "DATA_0000" lun configured in asm in this way
SQL> SELECT name, ...
- 1
0
votes
2
answers
364
views
Does an OFFLINE Database use space? [closed]
I took my SQL Server Database OFFLINE. Is it still occupying the same space as when it was ONLINE?
Should I keep it OFFLINE or is it better to BACKUP the database and DROP it?
- 11
0
votes
0
answers
86
views
How Blockchain Databases Work
I feel like I read somewhere back about blockchain databases but I can't seem to find anything too solid on the topic. This paper called Blockchain Databases doesn't offer much in terms of description....
- 175
1
vote
0
answers
253
views
"Slow Storage Writes on Drive T" warning from sp_Blitz
We migrated our platform to new SQL Server 2016 instances a couple of nights ago. Immediately following the migration, we ran sp_Blitz again, but noticed the following entry, which relates to the ...
- 535
5
votes
2
answers
2k
views
Is there a disk space impact when choosing NULL vs empty array {} for the default of an ARRAY[] column? [duplicate]
My intuition is NULL will take up less space than {} when used as the default value of an ARRAY[] column in PostgreSQL.
Am I correct?
- 331
0
votes
3
answers
385
views
Can I move / Modify the Object in Object Storage Service (OSS)
I am using Alibaba Cloud - ECS and have Storage Bucket - Object Storage Service (OSS).
File Storage structure is like
oss:/bucket/abc/xyz/123.jpg/
My Question is
Can I move or modify the objects ...
- 80
1
vote
0
answers
82
views
How should I organize my physical storage on 5 ssd single server for 2.2 TB database
I need to migrate a 2.2 TB database to a better organized single server with 12 physical cores. New server has 5 SATA SSDs 1 TB each, will upgrade to 6 SSDs 1 TB each.
My current design is (this is ...
- 11
10
votes
2
answers
404
views
Increased waits during checkpoint after upgrading to better storage
When we migrated from an older all flash array, to a newer all flash array (different, but well established vendor), we started seeing increased waits in SQL Sentry during checkpoints.
Version: ...
- 111
-3
votes
1
answer
92
views
Can we shrink a 1.6 TB SQL Server DB in Simple mode with only 12 GB Storage left?
We saw your article about this topic and wondered if you can answer this question:
Can we shrink a 1.6 TB SQL Server DB in Simple mode with only 12 GB Storage left?
Here is your article that we saw:
...
4
votes
1
answer
1k
views
How Graph Databases Store Data on Disk
I have seen these papers:
TurboGraph
GraphChi
BiShard Parallel Processor
G-Store
NXgraph
GridGraph
...and a few others. I am new to databases (other than having used them for web apps without ...
- 175
2
votes
1
answer
189
views
How to Store Trees on Disk
I am wondering how to store trees on a physical disk, for perhaps a tree-oriented database like an XML database.
Wikipedia states about XML databases:
...custom optimized data structures are used ...
- 175
2
votes
1
answer
91
views
How Database Formats Files for Disk
This SO answer outlines how MySQL organizes its database into files, but doesn't describe the structure of the files themselves.
I am wondering, at the physical level, how relational database ...
- 175