All Questions

18
votes
0answers
401 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 ...
10
votes
0answers
542 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 ...
8
votes
0answers
98 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
407 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
67 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
116 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 ...
7
votes
0answers
311 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
118 views

SQL dumping all pages from buffer cache every few minutes

I have a single SQL2012 SP4 node running several databases. The server has 20GB of memory available, 14GB allocated to SQL (nothing else running on the box). Every few minutes SQL dumps the whole ...
6
votes
0answers
235 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 ...
6
votes
0answers
52 views

Postgres: query planner not respecting table inheritance constraint when querying for null

I'm having an issue with slow queries that is caused by the planner checking every inherited table instead of only the one with the constraint. I have a table with 0 rows called "search_result". This ...
6
votes
0answers
907 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
818 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
513 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
361 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 ...
6
votes
0answers
6k views

What are the compression options for storing large amounts of text in Postgres?

I need to store large amounts of text in Postgres, mainly command logs and the output of long running commands and need to know if there are some settings that could help compress the data ...
5
votes
0answers
71 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 ...
5
votes
0answers
94 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 ...
5
votes
0answers
75 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
79 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 ...
5
votes
0answers
139 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
188 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 ...
5
votes
0answers
311 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
146 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
288 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
232 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
872 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
12k views

How do I install/enable the uuid-ossp extension on Postgres 9.3?

I’m using Postgres 9.3 on Ubuntu Linux 14.04. How do I install/enable the uuid-ossp extension? I first verified the contrib package was installed … root@prodbox:/home/rails/myproject# apt-get ...
5
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 ...
5
votes
0answers
853 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
379 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
438 views

Replication of specific tables using Postgres 9.4.4 and Amazon Web Services

I have currently setup a Postgres 9.4.4 RDS instance on Amazon Web Services. On this instance I hold 20 tables. In addition I also have Postgres 9.4.4 installed on my local server (OS: 64-bit Linux) ...
5
votes
0answers
565 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
732 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 * .... * ...
4
votes
0answers
83 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 ...
4
votes
0answers
55 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 ...
4
votes
0answers
54 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
48 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
67 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
71 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
201 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
156 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 ...
4
votes
0answers
1k views

Safely drop master key

I've restored a database in my Dev environment (SQL version 14.0.1000.169) and I'm using the wizard to create a "Availability Groups", when I try to select the database, I get a pop up "This database ...
4
votes
0answers
51 views

How to analyze postgres client process/session memory

Is there a way to check how much of process memory is allocated for the specific buffer for a running postgres session (work memory, temp buffers, plan cache etc ... )? I'm asking because i want to ...
4
votes
0answers
276 views

MongoDB background index builds block secondary

We recently experienced a disruptive incident in a MongoDB 3.2 cluster related to index creation. Scenario: Several indexes were created on the primary using background: true. Indexes were ...
4
votes
0answers
745 views

Primary node of MongoDB ReplicaSet constantly high cpu usage

We use mongo replicaSet version 3.4.2 on our production environments. The replicaSet works with 6 nodes , one primary and 5 secondaries. Few weeks ago we have started to get alerts on high cpu ...
4
votes
0answers
78 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 ...
4
votes
0answers
434 views

Extended Events - sqlserver.process_login_finish Not Firing?

We're trying to see whether a client is able to reach a database server, as it's receiving error: [DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied. The error ...
4
votes
0answers
732 views

Redshift: InternalError: cache lookup failed for relation

I have been speaking with Amazon support about this but their only solution is to "keep trying," which has not been successful. The issue is when running our ETL we intermittently get the following ...
4
votes
0answers
2k views

AWS RDS Postgres Logical replication

I am using AWS RDS Postgres's and RDS's logical replication support (Edit: Note, this is not the same as the logical replication featurein PostgreSQL 10. It's AWS RDS functionality based on the same ...

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