All Questions

18
votes
0answers
384 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
493 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
356 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
93 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
195 views

Blocking caused by Query Store. Unable to clear or disable

I recently updated our 2016 SQL Server to SP2 and the most recent CU (KB4458621) released in August 2018. Just in the last day or so, I noticed that I have some blocking going on. I can't kill the ...
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
213 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
44 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
693 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
781 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
276 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 ...
6
votes
0answers
479 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
353 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
54 views

SHRINKFILE Failure - Why does increasing file size resolve it?

I am running some SHRINKFILE operations to clean up a bunch of tiny, unnecessary files in a filegroup. For one of the shrinks, the command below results in an error: DBCC SHRINKFILE (N'myfile' , ...
5
votes
0answers
56 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
129 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
170 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
266 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
128 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
2k views

Trying to solve “outside tablespace bounds” MySQL error, but recovering table with mysqldump fails

I am running MySQL on a Windows 2008 server. One of the tables (> 1 million records) seems to be corrupted. The mysql error log shows this: InnoDB: Error: trying to access page number 197105 in space ...
5
votes
0answers
266 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
212 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
760 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
827 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
356 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
551 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
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
692 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
52 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 ...
4
votes
0answers
73 views

Query Notification Internals

I'm looking into using Query Notifications as a light(er) weight way of identifying when data in a table changes. I know they use Service Broker, and (although I have difficulty explaining exactly why)...
4
votes
0answers
44 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
69 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 ...
4
votes
0answers
61 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
57 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
98 views

What is the persistent_version_store table?

What is the purpose of the MS Shipped table: sys.persistent_version_store? Why do I want to know Primarily curiosity, partly because it may relate to an issue waiting to bite us... We're running a ...
4
votes
0answers
169 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
427 views

Unbelievably slow and unusable Query Store

I'm begining with Query Store and it's with problems :-( No report of Top Resource Consuming Queries is ever generated. It's just keep saying "Waiting" for hours and hours. Query on the background (...
4
votes
0answers
136 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
46 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
248 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
685 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
73 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
318 views

Replication doesn't resume once it fails to connect

We have MySQL replication running for our application. Right now the slave fails to resume if it fails to connect to the server for some time. We get the error below: [ERROR] Slave I/O: error ...
4
votes
0answers
691 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 ...
4
votes
0answers
248 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 ...
4
votes
0answers
150 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 (...
4
votes
0answers
111 views

Why `update` and `delete` acquire EXCLUSIVE lock rather than ROW EXCLUSIVE lock in Greenplum?

As we known, insert,update and delete commands automatically acquire ROW EXCLUSIVE lock in PostgreSQL. As a fork of PostgreSQL 8.2, why in Greenplum update and delete commands automatically acquire ...
4
votes
0answers
141 views

transaction chaining, isolation levels and atomicity

I'd like to ensure that I understand correctly how the concepts of transaction chaining, transaction isolation level and atomicity relate to each other. Here's my understanding: transaction chaining ...

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