Storing MemoryContext Pointers

Volkan YAZICI <yazicivo@ttnet.net.tr> writes:

When I allocate a new memory context via

oldmcxt = AllocSetContextCreate(TopMemoryContext, ...)
persistent_mcxt = CurrentMemoryContext;

ITYM

persistent_mcxt = AllocSetContextCreate(TopMemoryContext, ...)

because the other doesn't do what you think...

How can I store the persistent_mcxt in a persistent place that I'll be
able to reach it in my next getting invoked?

Make it a static variable.

regards, tom lane

On Oct 05 03:34, Tom Lane wrote:

Volkan YAZICI <yazicivo@ttnet.net.tr> writes:

When I allocate a new memory context via

oldmcxt = AllocSetContextCreate(TopMemoryContext, ...)
persistent_mcxt = CurrentMemoryContext;

ITYM

persistent_mcxt = AllocSetContextCreate(TopMemoryContext, ...)

Opps! Right. (I was looking at some MemoryContextSwitchTo() code while
typing above lines.)

because the other doesn't do what you think...

How can I store the persistent_mcxt in a persistent place that I'll be
able to reach it in my next getting invoked?

Make it a static variable.

I had thought some kind of fcinfo->flinfo->fn_extra trick but... a
static variable is fair enough too.

Thanks so much for the answer (also for your reply to caching subjected
post).

Regards.

Volkan YAZICI <yazicivo@ttnet.net.tr> writes:

On Oct 05 03:34, Tom Lane wrote:

Volkan YAZICI <yazicivo@ttnet.net.tr> writes:

How can I store the persistent_mcxt in a persistent place that I'll be
able to reach it in my next getting invoked?

Make it a static variable.

I had thought some kind of fcinfo->flinfo->fn_extra trick but... a
static variable is fair enough too.

No, a fn_extra pointer would go away whenever the calling query ends,
and you'd have leaked the context permanently. Children of
TopMemoryContext will never go away unless explicitly destroyed, so
a static variable has the right lifespan to remember them.

If you did want something that goes away at end of query, you could
probably make it a child of the PortalContext.

regards, tom lane