Re: pgbench: using prepared BEGIN statement in a pipeline could cause an error

I'm writing my own patch for this problem. While playing around with
it, I noticed this:

struct Command {
PQExpBufferData lines; /* 0 24 */
char * first_line; /* 24 8 */
int type; /* 32 4 */
MetaCommand meta; /* 36 4 */
int argc; /* 40 4 */

/* XXX 4 bytes hole, try to pack */

char * argv[256]; /* 48 2048 */
/* --- cacheline 32 boundary (2048 bytes) was 48 bytes ago --- */
char * varprefix; /* 2096 8 */
PgBenchExpr * expr; /* 2104 8 */
/* --- cacheline 33 boundary (2112 bytes) --- */
SimpleStats stats; /* 2112 40 */
int64 retries; /* 2152 8 */
int64 failures; /* 2160 8 */

/* size: 2168, cachelines: 34, members: 11 */
/* sum members: 2164, holes: 1, sum holes: 4 */
/* last cacheline: 56 bytes */
};

Not great. I suppose this makes pgbench slower than it needs to be.
Can we do better?

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"Nunca se desea ardientemente lo que solo se desea por razón" (F. Alexandre)