Re: Multi Inserts in CREATE TABLE AS - revived patch

Few things:

IIUC Andres mentioned similar kinds of APIs earlier in [1].

[1] -
https://www.postgresql.org/message-id/20200924024128.kyk3r5g7dnu3fxxx%40alap3.anarazel.de

I would like to add some more info to one of the API:

typedef struct MultiInsertStateData
{
MemoryContext micontext; /* A temporary memory context for
multi insert. */
BulkInsertStateData *bistate; /* Bulk insert state. */
TupleTableSlot **mislots; /* Array of buffered slots. */
uint32 nslots; /* Total number of buffered slots. */
int64 nbytes; /* Flush buffers if the total tuple size >=
nbytes. */
int32 nused; /* Number of current buffered slots for a
multi insert batch. */
int64 nsize; /* Total tuple size for a multi insert batch.
*/
} MultiInsertStateData;

/* Creates a temporary memory context, allocates the MultiInsertStateData,
BulkInsertStateData and initializes other members. */
void (*begin_multi_insert) (Relation rel, MultiInsertStateData
**mistate, uint32 nslots, uint64 nbytes);

/* Buffers the input slot into mistate slots, computes the size of the
tuple, and adds it total buffer tuple size, if this size crosses
mistate->nbytes, flush the buffered tuples into table. For heapam, existing
heap_multi_insert can be used. Once the buffer is flushed, then the
micontext can be reset and buffered slots can be cleared. *If nbytes i.e.
total tuple size of the batch is not given, tuple size is not calculated,
tuples are buffered until all the nslots are filled and then flushed.* */
void (*do_multi_insert) (Relation rel, MultiInsertStateData
*mistate, struct TupleTableSlot *slot, CommandId cid, int options);

/* Flush the buffered tuples if any. For heapam, existing heap_multi_insert
can be used. Deletes temporary memory context and deallocates mistate. */

void (*end_multi_insert) (Relation rel, MultiInsertStateData
*mistate, CommandId cid, int options);

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com