Known Issues for Multiplex Environment

Descriptions of known issues and workarounds for the multiplex environment.

Multiplex issues
CR#	Description
687591	Error during startup after coordinator failure – Under certain circumstances if the coordinator fails immediately after a checkpoint, it may fail to recover the correct blockmap unique ID and return a the following error during startup: I. 10/17 20:52:21. 0000000001 [20089]: Tried to insert a duplicate entry. -- (s_hashtb.cxx 290) Workaround – Use forced recovery on the coordinator and resynchronize all secondary servers. See System Administration Guide: Volume 1 > System Recovery and Database Repair > Forced Recovery Mode.
662254	Multiplex coordinator could deadlock with insufficient SA worker threads to service freelist requests – If you use IQ multiplex with DQP, the default setting of -gn is not enough to guarantee that some worker threads will always be available to service this request. Workaround – Set the -gn server startup flag. Calculate `GNn` considering the number of multiplex servers (`Sn`), the INC connection pool size on each secondary server (see database option `Mpx_Max_Connection_Pool_Size`, which defaults to 10 (`INCPn`)), and the number of user connections (`GMn`). The formula is: GNn = (Sn * INCPn) + GMn + 5 For example, if you have 20 multiplex servers with a `Mpx_Max_Connection_Pool_Size` of 10 and -gm is set to 50, then you set -gn to 255. If you are running the coordinator on a host that has greater than 32 cores, then you must set -iqmt. Make sure that the value of -iqmt is less than `(4000 - (GNn + 200))` to ensure that the total number of threads spawned by IQ does not exceed 4000.
611990	Emergency shutdown on secondary servers after CREATE TEXT INDEX – A secondary server goes into emergency shutdown, when: It is started with the -sf external_library_full_text flag, which disables loading of external libraries, and The user issues a CREATE TEXT INDEX statement on the coordinator with a text configuration that uses external libraries. All other servers replay the DDL successfully. Workaround – Start secondary nodes in the multiplex without the -sf external_library_full_text flag.
557714	Emergency shutdown on secondary servers after creating a proxy table – A timing problem may cause an emergency server shutdown when a user accesses a new proxy table on a secondary server. Workaround – Either reconnect or wait for some time and start another transaction, before trying to use a newly-created proxy table.