Unanswered Questions
14,250 questions with no upvoted or accepted answers
14
votes
0answers
230 views
Implementation and contraindications for OPTIMIZE_FOR_SEQUENTIAL_KEY
SQL Server 2019 CTP3.1 introduced an optimization to address last-page insert contention. This takes the form of an index option called OPTIMIZE_FOR_SEQUENTIAL_KEY.
One imagines this could be an ...
12
votes
1answer
8k 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 ...
11
votes
0answers
658 views
Splitting Snapshot files with MaxBCPThreads for Transactional Replication
I've just set up a publication, and I'm attempting to get the snapshot to apply faster. So far the Distribution Agent is respecting the MaxBCPThreads settings, but the Snapshot Agent is not. I'm ...
9
votes
1answer
743 views
HADR high worker thread usage
Why would an availability group's number of worker threads in an HADR pool increase well beyond minimum usage of "typically, there are 3–10 shared threads" per replica?
In one case we've observed ...
8
votes
0answers
452 views
UPDATE STATISTICS options fail in Amazon RDS SQL Server
In Amazon RDS SQL Server (any version/edition), create a temp table and update statistics on it. This works fine:
IF OBJECT_ID('tempdb..#t') IS NOT NULL
DROP TABLE #t;
GO
CREATE TABLE #t (id INT ...
8
votes
1answer
268 views
Do I need a “downtime” to update a stored procedure? (Due to “definition changed” error)
I always thought that updating a stored procedure was something I could do while users were actively using the system.
But I am currently testing out an update to a stored procedure and while a long ...
8
votes
0answers
499 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 ...
8
votes
1answer
21k views
Why does CAST(1 AS SIGNED INTEGER) return a BIGINT on MySQL?
If I do CAST(1 AS SIGNED INTEGER) I always end up getting a BIGINT returned, for example:
$ mysql -u root -p --column-type-info
Enter password:
--- Copyright and help message snipped for brevity ---
...
7
votes
0answers
135 views
SQL Server 2016 & 2017 Force Plan failing with reason 8695
I'm trying to force a plan using query store but it keeps failing with reason 8695 according to data in SYS.QUERY_STORE_PLAN the last_force_failure_reason_desc is 'General_Failure'.
Does anyone know ...
7
votes
0answers
123 views
What cases benefit from the Reduce, Replicate, and Redistribute join hints?
The From Clause Documentation starting with SQL Server 2008 briefly mention 3 join hints and their basic mechanisms:
Reduce
Replicate
Redistribute
However there does not seem to be much information ...
7
votes
0answers
280 views
Cardinality estimation on tables with large cardinality variance between keys
Context
I have stumbled on an issue in SQL Azure where the Sort-operator is spilling over into TempDB due to poor row estimates.
We are querying a master table that is joined with a number of detail ...
7
votes
3answers
833 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
1answer
610 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 ...
7
votes
2answers
319 views
Mongos not returning existing data in shards
So we have a configuration of 2 shard (each is a replica set) and one sharded collection.
There are around 10 million records in each shard. We are using mongo 2.6.4 version. We have sharded with ...
7
votes
1answer
761 views
Oracle Ref Partitioning: Deadlock due to child table row migration
My ordering application uses Oracle 11g Database. This DB has a primary table ORDERS and multiple child tables like ORDER_DETAILS, PLAN etc.
ORDERS table is LIST partitioned on STATUS column and all ...
