Unanswered Questions
26
votes
5answers
2k views
SQL Deadlock on the same exclusively locked clustered Key (with NHibernate) on delete / insert
I have been working on this deadlock issue for quite a few days now and no matter what I do, it persists in one way or another.
First, the general premise:
We have Visits with VisitItems in a one to ...
14
votes
0answers
264 views
Is it safe to add a new node to a Cassandra cluster while a repair is running?
I'm getting ready to expand an existing Cassandra cluster. I have repairs scheduled to run on a reoccurring basis. Do I need to disable repairs when adding a new node to a cluster, or can I ...
14
votes
0answers
339 views
9i streams capture doesn't evaluate rules
I have a streams replication set up between two oracle 9.2.0.8 instances as sources and an 11g instance as a destination, processing a small subset of data from each database (let it be one table ...
12
votes
1answer
523 views
How can I prevent UNPIVOT from being transformed into UNION ALL?
I have a somewhat complex Oracle query which is taking about half an hour to complete. If I take the slow part of the query and run it separately it finishes in a few seconds. Here's is a screenshot ...
11
votes
1answer
652 views
SQL Server 2016 vs 2012 insert performance
I have two SQL Server instances on the same server:
Microsoft SQL Server 2012 (SP1) - 11.0.3000.0 (X64) Standard Edition
(64-bit)
Microsoft SQL Server 2016 (SP1-CU5) (KB4040714) -
13.0.4451.0 (X64) ...
10
votes
0answers
95 views
Why is PostgreSQL choosing the more expensive join order?
PostgreSQL using defaults, plus
default_statistics_target=1000
random_page_cost=1.5
Version
PostgreSQL 10.4 on x86_64-pc-linux-musl, compiled by gcc (Alpine 6.4.0) 6.4.0, 64-bit
I've vacuumed and ...
10
votes
1answer
6k views
Use LDAP for name look up with Oracle Instant Client
Partly as a result of having problems with conflicting versions or bitness with the full installation of Oracle client, my development team (of which I'm a member) has been moving towards using Oracle ...
9
votes
1answer
123 views
Optimizing a 'latest' query in Postgres on 20M rows
My table looks as follows:
Column | Type |
-----------------------+-------------------+
id | integer |
source_id | integer ...
8
votes
1answer
162 views
Statistics on index on partitions not used in query on the whole table
The following join has very different row estimates when doing a join on the partitions vs when joining on the whole table:
CREATE TABLE m_data.ga_session (
session_id BIGINT ...
7
votes
2answers
104 views
Foreign Key with a Constant
Let's say I have a table A, that has two columns: one is an ID for ThingA, and one is an ID for ThingB. The primary key is (ThingA, ThingB).
Next, I have a second table, but this time it's restricted ...
7
votes
0answers
205 views
Why does RDS PostgreSQL always recover on restart?
I am running an RDS instance of PostgreSQL 9.6.3: select version(); returns PostgreSQL 9.6.3 on x86_64-pc-linux-gnu [...].
I have found that after issuing a stop from the RDS console followed by a ...
7
votes
1answer
864 views
Query External LDAP Server from SQL Server
I have done extensive research on querying LDAP Server but so far has not been able to work around. Therefore, asking experts help
Background: I have a client whose LDAP Server is OnPremise (though ...
7
votes
1answer
217 views
min()/max() on multi-column timestamp index
I'm finding it difficult to understand why there's a bunch of heap fetches going on in this query. To my understanding, when there's no nulls (at either end) in the index, reverse searching the index ...
7
votes
1answer
494 views
SQL Server Updated Record on Read-Only Filegroup?
I have a very large database in our data warehouse where we have implemented partitioning to manage maintenance and backups. Records of a certain age are eventually migrated to a read-only file group ...
7
votes
1answer
441 views
Convert query in words to relational algebra
I have a follow-up question to a question I have previously asked on SO.
Instead of the query from my initial question, I want to convert the following into relational algebra:
List the names and ...
