Spider FAQ
Contents
- What does "[ERROR] mysqld: Can't find record in 'spider_tables'" mean?
- Are there minimum Spider settings?
- What does "select spider_ping_table()" in the general log mean?
- Do I need a primary key on physical tables?
- Can I use Spider on top of Galera shards?
- What are the most used architectures for Spider HA?
- What are the most used architectures for Spider Map Reduce?
What does "[ERROR] mysqld: Can't find record in 'spider_tables'" mean?
This happens when you have a Spider table defined that does not point to an existing table on a data node.
Are there minimum Spider settings?
myisam-recover=FORCE,BACKUP
MariaDB until 10.1.1
optimizer_switch='engine_condition_pushdown=on'
MariaDB until 10.0.12
When using join_cache_level = 6 to get faster joins on the network it is recommended to use :
optimizer_switch='mrr=on,mrr_sort_keys=off'
What does "select spider_ping_table()" in the general log mean?
This is used by Spider monitoring to ask other monitoring nodes the status of a table.
Do I need a primary key on physical tables?
Not having a primary key will generate errors for resynchronizing tables via spider_copy_table().
Can I use Spider on top of Galera shards?
Yes, XA transactions can be disabled from Spider. Until Galera 4.0 fully supports xa transactions, spider can point to a maxscale proxy that can manage transparent node election in case of failure inside a shard group. Note that disabling XA will break cross shard WRITES in case of transaction ROLLBACK. This architecture need to be used with care if you have a highly transactional workload that can generate cross shard deadlocks.
What are the most used architectures for Spider HA?
- Delegation of shard node replication using asynchronous replication and slave election with GTID.
- Delegation of shard node replication via active passive HA solutions.
- Shard builds via replication into Spider tables is interesting when you can route READS to a pool of Spider nodes reattaching the shards.
What are the most used architectures for Spider Map Reduce?
- Map reduce in Spider is limited to a single table. Building spider on top of some views can eliminate the need to use joins.
- Replication to universal tables to every shard is commonly used to enable the views on each shard.