journal: by default do not decompress dat objects larger than 64K

This introduces a new data threshold setting for sd_journal objects
which controls the maximum size of objects to decompress. This is
relieves the library from having to decompress full data objects even
if a client program is only interested in the initial part of them.

This speeds up "systemd-coredumpctl" drastically when invoked without
parameters.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index cb93761bd1..ca5ad43b63 100644
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -91,7 +91,7 @@ static bool shall_print(const char *p, size_t l, OutputFlags flags) {
         if (flags & OUTPUT_SHOW_ALL)
                 return true;
 
-        if (l > PRINT_THRESHOLD)
+        if (l >= PRINT_THRESHOLD)
                 return false;
 
         if (!utf8_is_printable_n(p, l))
@@ -119,6 +119,8 @@ static int output_short(
         assert(f);
         assert(j);
 
+        sd_journal_set_data_threshold(j, flags & OUTPUT_SHOW_ALL ? 0 : PRINT_THRESHOLD);
+
         SD_JOURNAL_FOREACH_DATA(j, data, length) {
 
                 r = parse_field(data, length, "PRIORITY=", &priority, &priority_len);
@@ -308,6 +310,8 @@ static int output_verbose(
         assert(f);
         assert(j);
 
+        sd_journal_set_data_threshold(j, 0);
+
         r = sd_journal_get_realtime_usec(j, &realtime);
         if (r < 0) {
                 log_error("Failed to get realtime timestamp: %s", strerror(-r));
@@ -368,6 +372,8 @@ static int output_export(
 
         assert(j);
 
+        sd_journal_set_data_threshold(j, 0);
+
         r = sd_journal_get_realtime_usec(j, &realtime);
         if (r < 0) {
                 log_error("Failed to get realtime timestamp: %s", strerror(-r));
@@ -441,7 +447,7 @@ void json_escape(
         assert(f);
         assert(p);
 
-        if (!(flags & OUTPUT_SHOW_ALL) && l > JSON_THRESHOLD)
+        if (!(flags & OUTPUT_SHOW_ALL) && l >= JSON_THRESHOLD)
 
                 fputs("null", f);
 
@@ -502,6 +508,8 @@ static int output_json(
 
         assert(j);
 
+        sd_journal_set_data_threshold(j, flags & OUTPUT_SHOW_ALL ? 0 : JSON_THRESHOLD);
+
         r = sd_journal_get_realtime_usec(j, &realtime);
         if (r < 0) {
                 log_error("Failed to get realtime timestamp: %s", strerror(-r));
@@ -714,6 +722,8 @@ static int output_cat(
         assert(j);
         assert(f);
 
+        sd_journal_set_data_threshold(j, 0);
+
         r = sd_journal_get_data(j, "MESSAGE", &data, &l);
         if (r < 0) {
                 /* An entry without MESSAGE=? */