Records written to a CICS TDQ are buffered, and only flushed to disk when the buffer is full.  How do you stop writes to sequential files from using buffering?

Unless explicitly overriden using the EXTFH configuration file, writes to sequential files (including CICS TDQs) will be buffered,
and only flushed to disk when the file buffer is full. The default size of the buffer is 4096 bytes (4K), but can be overriden globally,
or for specific files, using the SEQDATBUF configuration option.

The following configuration options will cause all writes to the file SLV1DATA.tdq to be flushed to disk immediately, without buffering:-

[XFH-DEFAULT]  <-- Specify Global options
SEQDATBUF=8192 <-- Override the default buffer size
BASENAME=ON    <-- Allow the use of filenames without path names
[SLV1DATA.tdq] <-- Specify options for use with the file SLV1DATA.tdq
WRITETHRU=ON   <-- Flush all writes to this file immediately