From cea342c2cf2a3db299cac520299cb83ad8016ec6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 25 Feb 2025 19:10:12 -0500 Subject: [PATCH v2 2/2] Avoid unnecessary computation of pgbench's script line number. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ParseScript only needs the lineno for meta-commands, so let's not bother computing it otherwise. While this doesn't save much given the previous patch, there's no point in doing unnecessary work. While we're at it, avoid calling psql_scan_get_location() twice for a meta-command. One reason for making this change is that the line number computed in ParseScript's main loop was actually wrong in most cases: it would point just past the semicolon of the previous SQL command, not at what the user thinks the current command's line number is. We could add some code to skip whitespace before capturing the line number, but it would be pretty pointless at present. Just move the call to avoid the temptation to rely on that value. (Once we've lexed the backslash, the line number will be right.) This change also means that pgbench never inquires about the location before it's lexed something, so that the care taken in the previous patch to behave sanely in that case is unnecessary. It seems best to keep that logic, though, as future callers might depend on it. Author: Daniel Vérité Discussion: https://postgr.es/m/84a8a89e-adb8-47a9-9d34-c13f7150ee45@manitou-mail.org --- src/bin/pgbench/pgbench.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c index 38f8bc11bcd..bf099aab278 100644 --- a/src/bin/pgbench/pgbench.c +++ b/src/bin/pgbench/pgbench.c @@ -5677,22 +5677,17 @@ postprocess_sql_command(Command *my_command) * At call, we have scanned only the initial backslash. */ static Command * -process_backslash_command(PsqlScanState sstate, const char *source) +process_backslash_command(PsqlScanState sstate, const char *source, + int lineno, int start_offset) { Command *my_command; PQExpBufferData word_buf; int word_offset; int offsets[MAX_ARGS]; /* offsets of argument words */ - int start_offset; - int lineno; int j; initPQExpBuffer(&word_buf); - /* Remember location of the backslash */ - psql_scan_get_location(sstate, &lineno, &start_offset); - start_offset--; - /* Collect first word of command */ if (!expr_lex_one_word(sstate, &word_buf, &word_offset)) { @@ -5980,16 +5975,12 @@ ParseScript(const char *script, const char *desc, int weight) for (;;) { - int lineno; - int start_offset; PsqlScanResult sr; promptStatus_t prompt; Command *command = NULL; resetPQExpBuffer(&line_buf); - psql_scan_get_location(sstate, &lineno, &start_offset); - sr = psql_scan(sstate, &line_buf, &prompt); /* If we collected a new SQL command, process that */ @@ -6002,7 +5993,15 @@ ParseScript(const char *script, const char *desc, int weight) /* If we reached a backslash, process that */ if (sr == PSCAN_BACKSLASH) { - command = process_backslash_command(sstate, desc); + int lineno; + int start_offset; + + /* Capture location of the backslash */ + psql_scan_get_location(sstate, &lineno, &start_offset); + start_offset--; + + command = process_backslash_command(sstate, desc, + lineno, start_offset); if (command) { -- 2.43.5