All Questions

18
votes
0answers
415 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 ...
11
votes
0answers
589 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
0answers
126 views

Incorrect process utilization from System health extended events?

I have been recently working on understanding the data or metrics being stored in system health extended events event file. We are trying to implement the data collection of performance metrics using ...
8
votes
0answers
340 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
0answers
181 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
141 views

Statistics disappearing/empty randomly throughout the day

I've got a SQL Server 2017 (CU9) database that is exhibiting some performance related issues that I believe have to do with the index statistics. While troubleshooting I discovered that the ...
8
votes
0answers
453 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
0answers
94 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
93 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
257 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
0answers
345 views

CHANGE_TRACKING_CURRENT_VERSION() incorrect on database in standby

We are using a change tracking solution to export increments for BI purposes for years now. But it was running directly on the production database. To lower the load on the system we wanted it to run ...
7
votes
0answers
10k views

Conceptual data model for a billing system

I am working on existing MySQL database. My task is to create a new data model for a billing system on that existing application. I have created a conceptual data model (click to enlarge): ...
6
votes
0answers
95 views

dm_os_memory_cache_clock_hands understanding

As I mentioned in this question I'm trying to understand the working of clock hands. Simply put clock hands move when there is memory pressure so that cache entries can be removed or the cost can be ...
6
votes
0answers
1k views

Working on a decision tree database design

I'm doing the conceptual model for a Decision tree database. The goal is store any Decision tree. I have four entity types: DecisionTree, Node, Branch and Leaf. Each Decision tree is composed of ...
6
votes
0answers
232 views

SQL Server Profiler: why the RPC Starting event does use an different decimal separator from SP Starting?

Trying to diagnose an problem, I've ran into that inconsistency. In SQL Server Profiler, the RPC Starting event uses the regional settings to write real numbers (example: in Portuguese(Brazil) 14.5 ...
6
votes
0answers
848 views

SQLPackage : Import or Export SQL Azure BACPAC without users

I know how to use SQLpackage.exe. I can export from SQL Azure and create a bacpac. I can also Import to SQL Server via SQLPackage.exe. I want to export or import without the users in the database. ...
6
votes
0answers
548 views

How to minimize access exclusive table locks while reducing bloat or ALTER (ing) a table?

In some circumstances, I've been told not to do a VACUUM FULL (or CLUSTER) of a table that is in production, because that will exclusively lock it for longer than wished. The same might apply to ...
6
votes
0answers
1k views

Slow Postgresql query with left join

I have a query on Postgres, and I also have added proper index. Is there anything missing here? SELECT orders.*, demo.name as d_name FROM orders LEFT JOIN users as demo ON demo.id = orders.dr_id ...
6
votes
0answers
374 views

Roles and policies in Postgresql 9.5 row-level security

Following the the info in posts like these i would like to use the role system and policies, i.e. each user in my system would have a db role. I want to model the following properties but i can't come ...
5
votes
0answers
55 views

CMEMTHREAD waits during Index Optimisation in Availability Group

In a 3 node Availability group, a secondary replica will often become subject to redo lag due to the causes covered in Microsoft's documentation: Troubleshoot: Changes on the Primary Replica are not ...
5
votes
0answers
136 views

Alwayson AG lease timeout and healthcheck timeout

We have a physical SQL Server 2016 Enterprise SP2 with two instances and each instance contains one AG. Sometimes it happens that one AG goes to resolving (without failover), the cluster resource is ...
5
votes
0answers
110 views

Database design for ~ 2.7B rows per year / 26.000 data points every five minutes

The current situation We're currently looking into a new product that will send device data back to us to interpret. These are the numbers we're looking at: Devices will most likely send data every ...
5
votes
0answers
81 views

How do I identify the source of the 17886 errors (“server will drop the connection”) in my SQL errorlog?

I have a SQL 2012 server that is throwing the following error every 5 minutes or so: Error: 17886, Severity: 20, State: 1. The server will drop the connection, because the client driver has ...
5
votes
0answers
90 views

Which data model/schema to apply to a timeseries datastore for data sources with varying fields

I'm asked to develop a data-storage for time-series data, yet despite significant research I'm unsure about the data model and storage technology to chose. About the data The source data which is ...
5
votes
0answers
146 views

Using the Schema Generation Wizard to regenerate a previously-generated schema

Lately, I've been trying to clean up a group of projects that my company received from an outside contractor. Among them is an SSAS cube, with an associated data warehouse. The contractors generated ...
5
votes
0answers
185 views

Online index rebuild higher fragmentation on intermediate level

I need to rebuild some big indexes and I'm doing some tests with the various options (sort_in_tempdb, maxdop, online) of the ALTER INDEX statement on an test index with 4 levels and 800000 pages on ...
5
votes
0answers
356 views

Postgres 10 Logical Replication without truncating existing table

I have been fooling around with Postgres 10 logical replication, trying to learn about it and potentially apply it to a couple of projects. I have observed something that I am wondering about, but I ...
5
votes
0answers
177 views

UUID V1 and V4 bloats substantially after sequntial inserts and deletes. Why is it so, compared to serial and temporal BTree (which does not bloat)?

I am trying to understand the impact of deletions to bloat of tables and indexes after large number of inserts and deletes. The inserts and deletes are following a rather strict pattern: first the ...
5
votes
0answers
88 views

Deadlock in REDO thread , 1 replica went OK other didn't?

I have a 3 node cluster and the 2 secondaries initially went into SUSPECT mode due to a deadlock. I tried to resume both and only one caught up while the other is continuously deadlocking. I have to ...
5
votes
0answers
271 views

Should Full Text Filter Daemon Service be a cluster resource?

Our newly installed and configures Sql Server Always On Availability Failover Cluster with Sql 2016 Enterprise Edition with four instances and six nodes. It includes the DB Engine Service and the ...
5
votes
0answers
294 views

Performance degradation after upgrade from 3.0.11 to 3.2.12

Environment: CentoOS 6 (kernel 2.6.32), MongoDB community edition 3.0.11 and 3.2.12 , storage engine MMAP, config servers on SCCC We are experiencing performance degradation when moving from 3.0.11 ...
5
votes
0answers
193 views

IS_MEMBER() in Azure SQLDB not working for AD groups?

I am trying set up RLS and want to leverage AD groups. DB is created in Azure, and I know AD is working as I can connect using AD acount with SSMS First test Local Machine, is working as expected (...
5
votes
0answers
3k views

Postgres 9.6.1 Full Text Search dictionaries for most spoken languages

Using Mac OSX Yosemite 10.10.5, I am trying to run full text search operations, such as to_tsvector, to_tsquery, etc and have a need for dictionaries in about 80+ languages. Postgres seems to only ...
5
votes
0answers
251 views

Merge replication subscriptions are repeating the same actions endlessly

We have a merge publication set up on SQL Server 2008R2, with several subscribers. Synchronisation is done through the internet. Over the last few days, some subscribers are unable to synchronise. ...
5
votes
0answers
988 views

Why does pg_last_xact_replay_timestamp() sometimes return extremely old timestamps?

In PostgreSQL 9.5, to monitor streaming replication lag, I use a combination of: pg_current_xlog_location() pg_last_xlog_replay_location() pg_last_xact_replay_timestamp() The first two functions are ...
5
votes
0answers
874 views

Understanding MongoDB Log warning

In my MongoDB log, I am seeing these lines of messages: 2016-04-05T00:03:42.904+0000 I COMMAND [ftdc] serverStatus was very slow: { after basic: 200, after asserts: 240, after backgroundFlushing: ...
5
votes
0answers
397 views

How do transactions affect PostgreSQL's REFRESH MATERIALIZED VIEW CONCURRENTLY command?

PostgreSQL 9.4 supports REFRESH MATERIALIZED VIEW CONCURRENTLY. I'm not sure, but I think the REFRESH command is viewed as DDL by PostgreSQL, and PostgreSQL wraps all DDL within transactions so that ...
5
votes
0answers
582 views

Create an SSL connection with ODBC driver to MySQL(5.6) using openSSL

I want to create an asymmetric SSL connection from MySQL to an ODBC driver but don't fully know how to generate the keys and certificates (I'm using openSSL as recommended here: https://dev.mysql.com/...
5
votes
0answers
2k views

postgres \copy file to RDS timeout

Postgres version 9.3, hosted on Amazon RDS. I have a messages table with 10G of data. I connected the database using psql on the EC2. Then used \COPY (select * from messages) TO '/tmp/messages.csv' ...
5
votes
0answers
769 views

How to modelling a union type in PostgreSQL

We have the generic idea of a rule with specific implementation details stored in their own table. We currently have the following schema: Rule * id * name * ruleAId * ruleBId * .... * ...
5
votes
0answers
702 views

Intermittent SQL Server connectivity issues in production

I am running an ASP.NET based application, running on two load-balanced web servers, that communicate with a SQL Server 2008 R2 database running on a separate server on the same network in the ...
4
votes
0answers
41 views

How to know which DMVs relate to each other?

Is there any way to know which DMVs/DMFs are related to each other? Some of them are well known or obvious, like sys.dm_exec_connections JOIN sys.dm_exec_sessions ON session_id = session_id, or the ...
4
votes
0answers
70 views

Should I use Transactional Replication here?

I have a database on SQL Server A & one on SQL Server B. (SQL 2017 w/ enterprise) They share similar objects and need to be kept fairly up to date. Both will require changes to be passed to each ...
4
votes
0answers
50 views

Authoritative Extend Event object list?

I am looking for an authoritative list of objects for extended events, I want to know what version an object becomes available and some clues about what the value really represents. I have googled ...
4
votes
0answers
76 views

Can the Chase test algorithm only modify attributes on the right side of a functional dependency?

I'm attempting to apply the Chase Algorithm to determine if a decomposition is a lossless join decomposition. Functional Dependencies = {A → C, B → D, C → D, DE → C, CE → A} Here is my initial ...
4
votes
0answers
102 views

Error on rename for a column on a temporal table

I've come across an issue when renaming a column in a temporal table. I'm using entity framework to generate migrations, so most of the original SQL is generated, but that doesn't affect my issue. To ...
4
votes
0answers
173 views

Moving to version 2016 from 2008 and Breaking Change Alert from Upgrade Advisor

DBMS: SQL Server Upgrading from version 2008 to 2016. I have this part of the code that is being flagged by the Upgrade adviser as Breaking Change. Error: uses a constant expression which are ...
4
votes
0answers
86 views

PostgreSQL autovacuum ignoring “inactive” tables resulting in “transaction id wraparound”

I have a PostgreSQL database with a lot of tables (currently 93k) and I'm seeing issues with transaction id age threatening wraparound, because autovacuum is not getting triggered for clean tables ...
4
votes
0answers
215 views

RMAN-06169, but only when backing up via OEM 13c

When running a Level 1 or Level 0 backup via OEM 13c, the following RMAN error causes the run to fail. (The RMAN script is being ran with proper sysdba credentials from OEM 13c.) RMAN-06169: could ...
4
votes
0answers
912 views

Getting “Cannot open datafile for read-only” for an intentionally DROPped InnoDB table

It's been too long to remember how we got here accurately, but we get the following error on MySQL start (though it does still start the service with InnoDB): [ERROR] InnoDB: Cannot open datafile for ...

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